xref: /petsc/include/petscsnes.h (revision 3201ab8d70a3eea669f338f8bd746342de1cf5db)
1 /*
2     User interface for the nonlinear solvers package.
3 */
4 #pragma once
5 
6 #include <petscksp.h>
7 #include <petscdmtypes.h>
8 #include <petscfvtypes.h>
9 #include <petscdmdatypes.h>
10 #include <petscsnestypes.h>
11 
12 /* SUBMANSEC = SNES */
13 
14 /*J
15    SNESType - String with the name of a PETSc `SNES` method.
16 
17    Level: beginner
18 
19 .seealso: [](doc_nonlinsolve), [](ch_snes), `SNESSetType()`, `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFromOptions()`
20 J*/
21 typedef const char *SNESType;
22 #define SNESNEWTONLS         "newtonls"
23 #define SNESNEWTONTR         "newtontr"
24 #define SNESNEWTONTRDC       "newtontrdc"
25 #define SNESPYTHON           "python"
26 #define SNESNRICHARDSON      "nrichardson"
27 #define SNESKSPONLY          "ksponly"
28 #define SNESKSPTRANSPOSEONLY "ksptransposeonly"
29 #define SNESVINEWTONRSLS     "vinewtonrsls"
30 #define SNESVINEWTONSSLS     "vinewtonssls"
31 #define SNESNGMRES           "ngmres"
32 #define SNESQN               "qn"
33 #define SNESSHELL            "shell"
34 #define SNESNGS              "ngs"
35 #define SNESNCG              "ncg"
36 #define SNESFAS              "fas"
37 #define SNESMS               "ms"
38 #define SNESNASM             "nasm"
39 #define SNESANDERSON         "anderson"
40 #define SNESASPIN            "aspin"
41 #define SNESCOMPOSITE        "composite"
42 #define SNESPATCH            "patch"
43 #define SNESNEWTONAL         "newtonal"
44 
45 /* Logging support */
46 PETSC_EXTERN PetscClassId SNES_CLASSID;
47 PETSC_EXTERN PetscClassId DMSNES_CLASSID;
48 
49 PETSC_EXTERN PetscErrorCode SNESInitializePackage(void);
50 PETSC_EXTERN PetscErrorCode SNESFinalizePackage(void);
51 
52 PETSC_EXTERN PetscErrorCode SNESCreate(MPI_Comm, SNES *);
53 PETSC_EXTERN PetscErrorCode SNESParametersInitialize(SNES);
54 PETSC_EXTERN PetscErrorCode SNESReset(SNES);
55 PETSC_EXTERN PetscErrorCode SNESDestroy(SNES *);
56 PETSC_EXTERN PetscErrorCode SNESSetType(SNES, SNESType);
57 PETSC_EXTERN PetscErrorCode SNESMonitor(SNES, PetscInt, PetscReal);
58 PETSC_EXTERN PetscErrorCode SNESMonitorSet(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *), void *, PetscErrorCode (*)(void **));
59 PETSC_EXTERN PetscErrorCode SNESMonitorSetFromOptions(SNES, const char[], const char[], const char[], PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscViewerAndFormat *), PetscErrorCode (*)(SNES, PetscViewerAndFormat *));
60 PETSC_EXTERN PetscErrorCode SNESMonitorCancel(SNES);
61 PETSC_EXTERN PetscErrorCode SNESMonitorSAWs(SNES, PetscInt, PetscReal, void *);
62 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsCreate(SNES, void **);
63 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsDestroy(void **);
64 PETSC_EXTERN PetscErrorCode SNESSetConvergenceHistory(SNES, PetscReal[], PetscInt[], PetscInt, PetscBool);
65 PETSC_EXTERN PetscErrorCode SNESGetConvergenceHistory(SNES, PetscReal *[], PetscInt *[], PetscInt *);
66 PETSC_EXTERN PetscErrorCode SNESSetUp(SNES);
67 PETSC_EXTERN PetscErrorCode SNESSolve(SNES, Vec, Vec);
68 PETSC_EXTERN PetscErrorCode SNESSetErrorIfNotConverged(SNES, PetscBool);
69 PETSC_EXTERN PetscErrorCode SNESGetErrorIfNotConverged(SNES, PetscBool *);
70 PETSC_EXTERN PetscErrorCode SNESConverged(SNES, PetscInt, PetscReal, PetscReal, PetscReal);
71 
72 PETSC_EXTERN PetscErrorCode SNESSetWorkVecs(SNES, PetscInt);
73 
74 PETSC_EXTERN PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*)(SNES));
75 
76 PETSC_EXTERN PetscErrorCode SNESRegister(const char[], PetscErrorCode (*)(SNES));
77 
78 PETSC_EXTERN PetscErrorCode SNESGetKSP(SNES, KSP *);
79 PETSC_EXTERN PetscErrorCode SNESSetKSP(SNES, KSP);
80 PETSC_EXTERN PetscErrorCode SNESSetSolution(SNES, Vec);
81 PETSC_EXTERN PetscErrorCode SNESGetSolution(SNES, Vec *);
82 PETSC_EXTERN PetscErrorCode SNESGetSolutionUpdate(SNES, Vec *);
83 PETSC_EXTERN PetscErrorCode SNESGetRhs(SNES, Vec *);
84 PETSC_EXTERN PetscErrorCode SNESView(SNES, PetscViewer);
85 PETSC_EXTERN PetscErrorCode SNESLoad(SNES, PetscViewer);
86 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewSet(SNES, PetscErrorCode (*)(SNES, void *), void *, PetscErrorCode (*)(void **));
87 PETSC_EXTERN PetscErrorCode SNESViewFromOptions(SNES, PetscObject, const char[]);
88 PETSC_EXTERN PetscErrorCode SNESConvergedReasonView(SNES, PetscViewer);
89 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewFromOptions(SNES);
90 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewCancel(SNES);
91 
92 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonView()", ) static inline PetscErrorCode SNESReasonView(SNES snes, PetscViewer v)
93 {
94   return SNESConvergedReasonView(snes, v);
95 }
96 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonViewFromOptions()", ) static inline PetscErrorCode SNESReasonViewFromOptions(SNES snes)
97 {
98   return SNESConvergedReasonViewFromOptions(snes);
99 }
100 
101 #define SNES_FILE_CLASSID 1211224
102 
103 PETSC_EXTERN PetscErrorCode SNESSetOptionsPrefix(SNES, const char[]);
104 PETSC_EXTERN PetscErrorCode SNESAppendOptionsPrefix(SNES, const char[]);
105 PETSC_EXTERN PetscErrorCode SNESGetOptionsPrefix(SNES, const char *[]);
106 PETSC_EXTERN PetscErrorCode SNESSetFromOptions(SNES);
107 PETSC_EXTERN PetscErrorCode SNESResetFromOptions(SNES);
108 
109 PETSC_EXTERN PetscErrorCode SNESSetUseMatrixFree(SNES, PetscBool, PetscBool);
110 PETSC_EXTERN PetscErrorCode SNESGetUseMatrixFree(SNES, PetscBool *, PetscBool *);
111 PETSC_EXTERN PetscErrorCode MatCreateSNESMF(SNES, Mat *);
112 PETSC_EXTERN PetscErrorCode MatSNESMFGetSNES(Mat, SNES *);
113 PETSC_EXTERN PetscErrorCode MatSNESMFSetReuseBase(Mat, PetscBool);
114 PETSC_EXTERN PetscErrorCode MatSNESMFGetReuseBase(Mat, PetscBool *);
115 PETSC_EXTERN PetscErrorCode MatMFFDComputeJacobian(SNES, Vec, Mat, Mat, void *);
116 PETSC_EXTERN PetscErrorCode MatCreateSNESMFMore(SNES, Vec, Mat *);
117 PETSC_EXTERN PetscErrorCode MatSNESMFMoreSetParameters(Mat, PetscReal, PetscReal, PetscReal);
118 
119 PETSC_EXTERN PetscErrorCode SNESGetType(SNES, SNESType *);
120 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultSetUp(SNES, PetscViewerAndFormat *);
121 PETSC_EXTERN PetscErrorCode SNESMonitorDefault(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
122 PETSC_EXTERN PetscErrorCode SNESMonitorScaling(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
123 PETSC_EXTERN PetscErrorCode SNESMonitorRange(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
124 PETSC_EXTERN PetscErrorCode SNESMonitorRatio(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
125 PETSC_EXTERN PetscErrorCode SNESMonitorRatioSetUp(SNES, PetscViewerAndFormat *);
126 PETSC_EXTERN PetscErrorCode SNESMonitorSolution(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
127 PETSC_EXTERN PetscErrorCode SNESMonitorResidual(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
128 PETSC_EXTERN PetscErrorCode SNESMonitorSolutionUpdate(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
129 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultShort(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
130 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultField(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
131 PETSC_EXTERN PetscErrorCode SNESMonitorJacUpdateSpectrum(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
132 PETSC_EXTERN PetscErrorCode SNESMonitorFields(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
133 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidual(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
134 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLG(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
135 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLGCreate(PetscViewer, PetscViewerFormat, void *, PetscViewerAndFormat **);
136 
137 PETSC_EXTERN PetscErrorCode SNESSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt, PetscInt);
138 PETSC_EXTERN PetscErrorCode SNESSetDivergenceTolerance(SNES, PetscReal);
139 PETSC_EXTERN PetscErrorCode SNESGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *, PetscInt *);
140 PETSC_EXTERN PetscErrorCode SNESGetDivergenceTolerance(SNES, PetscReal *);
141 PETSC_EXTERN PetscErrorCode SNESGetForceIteration(SNES, PetscBool *);
142 PETSC_EXTERN PetscErrorCode SNESSetForceIteration(SNES, PetscBool);
143 PETSC_EXTERN PetscErrorCode SNESGetIterationNumber(SNES, PetscInt *);
144 PETSC_EXTERN PetscErrorCode SNESSetIterationNumber(SNES, PetscInt);
145 
146 /*E
147    SNESNewtonTRFallbackType - type of fallback in case the solution of the trust-region subproblem is outside of the radius
148 
149    Values:
150 +  `SNES_TR_FALLBACK_NEWTON` - use scaled Newton step
151 .  `SNES_TR_FALLBACK_CAUCHY` - use Cauchy direction
152 -  `SNES_TR_FALLBACK_DOGLEG` - use dogleg method
153 
154    Level: intermediate
155 
156 .seealso: [](ch_snes), `SNES`, `SNESNEWTONTR`, `SNESNEWTONTRDC`
157 E*/
158 typedef enum {
159   SNES_TR_FALLBACK_NEWTON,
160   SNES_TR_FALLBACK_CAUCHY,
161   SNES_TR_FALLBACK_DOGLEG,
162 } SNESNewtonTRFallbackType;
163 
164 PETSC_EXTERN const char *const SNESNewtonTRFallbackTypes[];
165 
166 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetPreCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, PetscBool *, void *), void *ctx);
167 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetPreCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, PetscBool *, void *), void **ctx);
168 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetPostCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
169 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetPostCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
170 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetFallbackType(SNES, SNESNewtonTRFallbackType);
171 PETSC_EXTERN PetscErrorCode SNESNewtonTRPreCheck(SNES, Vec, Vec, PetscBool *);
172 PETSC_EXTERN PetscErrorCode SNESNewtonTRPostCheck(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *);
173 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetNormType(SNES, NormType);
174 
175 /*E
176     SNESNewtonTRQNType - type of quasi-Newton model to use
177 
178    Values:
179 +  `SNES_TR_QN_NONE` - do not use a quasi-Newton model
180 .  `SNES_TR_QN_SAME` - use the same quasi-Newton model for matrix and preconditioner
181 -  `SNES_TR_QN_DIFFERENT` - use different quasi-Newton models for matrix and preconditioner
182 
183    Level: intermediate
184 
185 .seealso: [](ch_snes), `SNES`, `SNESNEWTONTR`
186 E*/
187 typedef enum {
188   SNES_TR_QN_NONE,
189   SNES_TR_QN_SAME,
190   SNES_TR_QN_DIFFERENT,
191 } SNESNewtonTRQNType;
192 
193 PETSC_EXTERN const char *const SNESNewtonTRQNTypes[];
194 
195 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetQNType(SNES, SNESNewtonTRQNType);
196 
197 PETSC_EXTERN PETSC_DEPRECATED_FUNCTION(3, 22, 0, "SNESNewtonTRSetTolerances()", ) PetscErrorCode SNESSetTrustRegionTolerance(SNES, PetscReal);
198 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetTolerances(SNES, PetscReal, PetscReal, PetscReal);
199 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *);
200 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetUpdateParameters(SNES, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal);
201 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetUpdateParameters(SNES, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *);
202 
203 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetRhoFlag(SNES, PetscBool *);
204 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPreCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, PetscBool *, void *), void *ctx);
205 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPreCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, PetscBool *, void *), void **ctx);
206 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPostCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
207 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPostCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
208 
209 PETSC_EXTERN PetscErrorCode SNESGetNonlinearStepFailures(SNES, PetscInt *);
210 PETSC_EXTERN PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES, PetscInt);
211 PETSC_EXTERN PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES, PetscInt *);
212 PETSC_EXTERN PetscErrorCode SNESGetNumberFunctionEvals(SNES, PetscInt *);
213 
214 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditioner(SNES, PetscInt);
215 PETSC_EXTERN PetscErrorCode SNESGetLagPreconditioner(SNES, PetscInt *);
216 PETSC_EXTERN PetscErrorCode SNESSetLagJacobian(SNES, PetscInt);
217 PETSC_EXTERN PetscErrorCode SNESGetLagJacobian(SNES, PetscInt *);
218 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditionerPersists(SNES, PetscBool);
219 PETSC_EXTERN PetscErrorCode SNESSetLagJacobianPersists(SNES, PetscBool);
220 PETSC_EXTERN PetscErrorCode SNESSetGridSequence(SNES, PetscInt);
221 PETSC_EXTERN PetscErrorCode SNESGetGridSequence(SNES, PetscInt *);
222 
223 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveIterations(SNES, PetscInt *);
224 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveFailures(SNES, PetscInt *);
225 PETSC_EXTERN PetscErrorCode SNESSetMaxLinearSolveFailures(SNES, PetscInt);
226 PETSC_EXTERN PetscErrorCode SNESGetMaxLinearSolveFailures(SNES, PetscInt *);
227 PETSC_EXTERN PetscErrorCode SNESSetCountersReset(SNES, PetscBool);
228 
229 PETSC_EXTERN PetscErrorCode SNESKSPSetUseEW(SNES, PetscBool);
230 PETSC_EXTERN PetscErrorCode SNESKSPGetUseEW(SNES, PetscBool *);
231 PETSC_EXTERN PetscErrorCode SNESKSPSetParametersEW(SNES, PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal);
232 PETSC_EXTERN PetscErrorCode SNESKSPGetParametersEW(SNES, PetscInt *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *);
233 
234 #include <petscdrawtypes.h>
235 PETSC_EXTERN PetscErrorCode SNESMonitorLGRange(SNES, PetscInt, PetscReal, void *);
236 
237 PETSC_EXTERN PetscErrorCode SNESSetApplicationContext(SNES, void *);
238 PETSC_EXTERN PetscErrorCode SNESGetApplicationContext(SNES, void *);
239 PETSC_EXTERN PetscErrorCode SNESSetComputeApplicationContext(SNES, PetscErrorCode (*)(SNES, void **), PetscErrorCode (*)(void **));
240 
241 PETSC_EXTERN PetscErrorCode SNESPythonSetType(SNES, const char[]);
242 PETSC_EXTERN PetscErrorCode SNESPythonGetType(SNES, const char *[]);
243 
244 PETSC_EXTERN PetscErrorCode SNESSetFunctionDomainError(SNES);
245 PETSC_EXTERN PetscErrorCode SNESGetFunctionDomainError(SNES, PetscBool *);
246 PETSC_EXTERN PetscErrorCode SNESGetJacobianDomainError(SNES, PetscBool *);
247 PETSC_EXTERN PetscErrorCode SNESSetJacobianDomainError(SNES);
248 PETSC_EXTERN PetscErrorCode SNESSetCheckJacobianDomainError(SNES, PetscBool);
249 PETSC_EXTERN PetscErrorCode SNESGetCheckJacobianDomainError(SNES, PetscBool *);
250 
251 #define SNES_CONVERGED_TR_DELTA_DEPRECATED SNES_CONVERGED_TR_DELTA PETSC_DEPRECATED_ENUM(3, 12, 0, "SNES_DIVERGED_TR_DELTA", )
252 /*E
253     SNESConvergedReason - reason a `SNESSolve()` was determined to have converged or diverged
254 
255    Values:
256 +  `SNES_CONVERGED_FNORM_ABS`      - 2-norm(F) <= abstol
257 .  `SNES_CONVERGED_FNORM_RELATIVE` - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
258 .  `SNES_CONVERGED_SNORM_RELATIVE` - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
259 .  `SNES_DIVERGED_FUNCTION_COUNT`  - The user provided function has been called more times than the maximum set in `SNESSetTolerances()`
260 .  `SNES_DIVERGED_DTOL`            - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
261 .  `SNES_DIVERGED_FNORM_NAN`       - the 2-norm of the current function evaluation is not-a-number (NaN), this
262                                      is usually caused by a division of 0 by 0.
263 .  `SNES_DIVERGED_MAX_IT`          - `SNESSolve()` has reached the maximum number of iterations requested
264 .  `SNES_DIVERGED_LINE_SEARCH`     - The line search has failed. This only occurs for `SNES` solvers that use a line search
265 .  `SNES_DIVERGED_LOCAL_MIN`       - the algorithm seems to have stagnated at a local minimum that is not zero.
266 -  `SNES_CONERGED_ITERATING`       - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
267 
268    Level: beginner
269 
270     Notes:
271    The two most common reasons for divergence are an incorrectly coded or computed Jacobian or failure or lack of convergence in the linear system (in this case we recommend
272    testing with `-pc_type lu` to eliminate the linear solver as the cause of the problem).
273 
274    `SNES_DIVERGED_LOCAL_MIN` can only occur when using the line-search variant of `SNES`.
275    The line search wants to minimize Q(alpha) = 1/2 || F(x + alpha s) ||^2_2  this occurs
276    at Q'(alpha) = s^T F'(x+alpha s)^T F(x+alpha s) = 0. If s is the Newton direction - F'(x)^(-1)F(x) then
277    you get Q'(alpha) = -F(x)^T F'(x)^(-1)^T F'(x+alpha s)F(x+alpha s); when alpha = 0
278    Q'(0) = - ||F(x)||^2_2 which is always NEGATIVE if F'(x) is invertible. This means the Newton
279    direction is a descent direction and the line search should succeed if alpha is small enough.
280 
281    If F'(x) is NOT invertible AND F'(x)^T F(x) = 0 then Q'(0) = 0 and the Newton direction
282    is NOT a descent direction so the line search will fail. All one can do at this point
283    is change the initial guess and try again.
284 
285    An alternative explanation: Newton's method can be regarded as replacing the function with
286    its linear approximation and minimizing the 2-norm of that. That is F(x+s) approx F(x) + F'(x)s
287    so we minimize || F(x) + F'(x) s ||^2_2; do this using Least Squares. If F'(x) is invertible then
288    s = - F'(x)^(-1)F(x) otherwise F'(x)^T F'(x) s = -F'(x)^T F(x). If F'(x)^T F(x) is NOT zero then there
289    exists a nontrivial (that is F'(x)s != 0) solution to the equation and this direction is
290    s = - [F'(x)^T F'(x)]^(-1) F'(x)^T F(x) so Q'(0) = - F(x)^T F'(x) [F'(x)^T F'(x)]^(-T) F'(x)^T F(x)
291    = - (F'(x)^T F(x)) [F'(x)^T F'(x)]^(-T) (F'(x)^T F(x)). Since we are assuming (F'(x)^T F(x)) != 0
292    and F'(x)^T F'(x) has no negative eigenvalues Q'(0) < 0 so s is a descent direction and the line
293    search should succeed for small enough alpha.
294 
295    Note that this RARELY happens in practice. Far more likely the linear system is not being solved
296    (well enough?) or the Jacobian is wrong.
297 
298    `SNES_DIVERGED_MAX_IT` means that the solver reached the maximum number of iterations without satisfying any
299    convergence criteria. `SNES_CONVERGED_ITS` means that `SNESConvergedSkip()` was chosen as the convergence test;
300    thus the usual convergence criteria have not been checked and may or may not be satisfied.
301 
302 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`, `SNESSetTolerances()`
303 E*/
304 typedef enum {                       /* converged */
305   SNES_CONVERGED_FNORM_ABS      = 2, /* ||F|| < atol */
306   SNES_CONVERGED_FNORM_RELATIVE = 3, /* ||F|| < rtol*||F_initial|| */
307   SNES_CONVERGED_SNORM_RELATIVE = 4, /* Newton computed step size small; || delta x || < stol || x ||*/
308   SNES_CONVERGED_ITS            = 5, /* maximum iterations reached */
309   SNES_BREAKOUT_INNER_ITER      = 6, /* Flag to break out of inner loop after checking custom convergence. */
310                                      /* it is used in multi-phase flow when state changes */
311   /* diverged */
312   SNES_DIVERGED_FUNCTION_DOMAIN      = -1, /* the new x location passed the function is not in the domain of F */
313   SNES_DIVERGED_FUNCTION_COUNT       = -2,
314   SNES_DIVERGED_LINEAR_SOLVE         = -3, /* the linear solve failed */
315   SNES_DIVERGED_FNORM_NAN            = -4,
316   SNES_DIVERGED_MAX_IT               = -5,
317   SNES_DIVERGED_LINE_SEARCH          = -6,  /* the line search failed */
318   SNES_DIVERGED_INNER                = -7,  /* inner solve failed */
319   SNES_DIVERGED_LOCAL_MIN            = -8,  /* || J^T b || is small, implies converged to local minimum of F() */
320   SNES_DIVERGED_DTOL                 = -9,  /* || F || > divtol*||F_initial|| */
321   SNES_DIVERGED_JACOBIAN_DOMAIN      = -10, /* Jacobian calculation does not make sense */
322   SNES_DIVERGED_TR_DELTA             = -11,
323   SNES_CONVERGED_TR_DELTA_DEPRECATED = -11,
324 
325   SNES_CONVERGED_ITERATING = 0
326 } SNESConvergedReason;
327 PETSC_EXTERN const char *const *SNESConvergedReasons;
328 
329 /*MC
330    SNES_CONVERGED_FNORM_ABS - 2-norm(F) <= abstol
331 
332    Level: beginner
333 
334 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
335 M*/
336 
337 /*MC
338    SNES_CONVERGED_FNORM_RELATIVE - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
339 
340    Level: beginner
341 
342 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
343 M*/
344 
345 /*MC
346   SNES_CONVERGED_SNORM_RELATIVE - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
347   solution and stol is the 4th argument to `SNESSetTolerances()`
348 
349   Options Database Key:
350   -snes_stol <stol> - the step tolerance
351 
352    Level: beginner
353 
354 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
355 M*/
356 
357 /*MC
358    SNES_DIVERGED_FUNCTION_COUNT - The user provided function has been called more times then the final
359    argument to `SNESSetTolerances()`
360 
361    Level: beginner
362 
363 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
364 M*/
365 
366 /*MC
367    SNES_DIVERGED_DTOL - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
368 
369    Level: beginner
370 
371 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESSetDivergenceTolerance()`
372 M*/
373 
374 /*MC
375    SNES_DIVERGED_FNORM_NAN - the 2-norm of the current function evaluation is not-a-number (NaN), this
376    is usually caused by a division of 0 by 0.
377 
378    Level: beginner
379 
380 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
381 M*/
382 
383 /*MC
384    SNES_DIVERGED_MAX_IT - SNESSolve() has reached the maximum number of iterations requested
385 
386    Level: beginner
387 
388 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
389 M*/
390 
391 /*MC
392    SNES_DIVERGED_LINE_SEARCH - The line search has failed. This only occurs for a `SNES` solvers that use a line search
393 
394    Level: beginner
395 
396 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESLineSearch`
397 M*/
398 
399 /*MC
400    SNES_DIVERGED_LOCAL_MIN - the algorithm seems to have stagnated at a local minimum that is not zero.
401    See the manual page for `SNESConvergedReason` for more details
402 
403    Level: beginner
404 
405 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
406 M*/
407 
408 /*MC
409    SNES_CONERGED_ITERATING - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
410 
411    Level: beginner
412 
413 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
414 M*/
415 
416 PETSC_EXTERN PetscErrorCode SNESSetConvergenceTest(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *, PetscErrorCode (*)(void *));
417 PETSC_EXTERN PetscErrorCode SNESConvergedDefault(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
418 PETSC_EXTERN PetscErrorCode SNESConvergedSkip(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
419 PETSC_EXTERN PetscErrorCode SNESConvergedCorrectPressure(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
420 PETSC_EXTERN PetscErrorCode SNESGetConvergedReason(SNES, SNESConvergedReason *);
421 PETSC_EXTERN PetscErrorCode SNESGetConvergedReasonString(SNES, const char **);
422 PETSC_EXTERN PetscErrorCode SNESSetConvergedReason(SNES, SNESConvergedReason);
423 
424 PETSC_DEPRECATED_FUNCTION(3, 5, 0, "SNESConvergedSkip()", ) static inline void SNESSkipConverged(void)
425 { /* never called */
426 }
427 #define SNESSkipConverged (SNESSkipConverged, SNESConvergedSkip)
428 
429 /*S
430   SNESInitialGuessFn - A prototype of a `SNES` compute initial guess function that would be passed to `SNESSetComputeInitialGuess()`
431 
432   Calling Sequence:
433 + snes  - `SNES` context
434 . u   - output vector to contain initial guess
435 - ctx - [optional] user-defined function context
436 
437   Level: beginner
438 
439 .seealso: [](ch_snes), `SNES`, `SNESSetComputeInitialGuess()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESFunctionFn`
440 S*/
441 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESInitialGuessFn)(SNES snes, Vec u, void *ctx);
442 
443 /*S
444   SNESFunctionFn - A prototype of a `SNES` evaluation function that would be passed to `SNESSetFunction()`
445 
446   Calling Sequence:
447 + snes  - `SNES` context
448 . u   - input vector
449 . F   - function vector
450 - ctx - [optional] user-defined function context
451 
452   Level: beginner
453 
454 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
455 S*/
456 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESFunctionFn)(SNES snes, Vec u, Vec F, void *ctx);
457 
458 /*S
459   SNESObjectiveFn - A prototype of a `SNES` objective evaluation function that would be passed to `SNESSetObjective()`
460 
461   Calling Sequence:
462 + snes  - `SNES` context
463 . u   - input vector
464 . o   - output value
465 - ctx - [optional] user-defined function context
466 
467   Level: beginner
468 
469 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
470 S*/
471 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESObjectiveFn)(SNES snes, Vec u, PetscReal *o, void *ctx);
472 
473 /*S
474   SNESJacobianFn - A prototype of a `SNES` Jacobian evaluation function that would be passed to `SNESSetJacobian()`
475 
476   Calling Sequence:
477 + snes   - the `SNES` context obtained from `SNESCreate()`
478 . u    - input vector
479 . Amat - (approximate) Jacobian matrix
480 . Pmat - matrix used to construct the preconditioner, often the same as `Amat`
481 - ctx  - [optional] user-defined context for matrix evaluation routine
482 
483   Level: beginner
484 
485 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESNGSFn`
486 S*/
487 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESJacobianFn)(SNES snes, Vec u, Mat Amat, Mat Pmat, void *ctx);
488 
489 /*S
490   SNESNGSFn - A prototype of a `SNES` nonlinear Gauss-Seidel function that would be passed to `SNESSetNGS()`
491 
492   Calling Sequence:
493 + snes   - the `SNES` context obtained from `SNESCreate()`
494 . u    - the current solution, updated in place
495 . b    - the right-hand side vector (which may be `NULL`)
496 - ctx  - [optional] user-defined context for matrix evaluation routine
497 
498   Level: beginner
499 
500 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`
501 S*/
502 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESNGSFn)(SNES snes, Vec u, Vec b, void *ctx);
503 
504 /*S
505   SNESUpdateFn - A prototype of a `SNES` update function that would be passed to `SNESSetUpdate()`
506 
507   Calling Sequence:
508 + snes - `SNES` context
509 - step - the current iteration index
510 
511   Level: advanced
512 
513 .seealso: [](ch_snes), `SNES`, `SNESSetUpdate()`
514 S*/
515 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESUpdateFn)(SNES snes, PetscInt step);
516 
517 /* --------- Solving systems of nonlinear equations --------------- */
518 PETSC_EXTERN PetscErrorCode SNESSetFunction(SNES, Vec, SNESFunctionFn *, void *);
519 PETSC_EXTERN PetscErrorCode SNESGetFunction(SNES, Vec *, SNESFunctionFn **, void **);
520 PETSC_EXTERN PetscErrorCode SNESComputeFunction(SNES, Vec, Vec);
521 PETSC_EXTERN PetscErrorCode SNESComputeMFFunction(SNES, Vec, Vec);
522 PETSC_EXTERN PetscErrorCode SNESSetInitialFunction(SNES, Vec);
523 
524 PETSC_EXTERN PetscErrorCode SNESSetJacobian(SNES, Mat, Mat, SNESJacobianFn *, void *);
525 PETSC_EXTERN PetscErrorCode SNESGetJacobian(SNES, Mat *, Mat *, SNESJacobianFn **, void **);
526 PETSC_EXTERN SNESFunctionFn SNESObjectiveComputeFunctionDefaultFD;
527 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefault;
528 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefaultColor;
529 PETSC_EXTERN PetscErrorCode SNESPruneJacobianColor(SNES, Mat, Mat);
530 PETSC_EXTERN PetscErrorCode SNESSetComputeInitialGuess(SNES, SNESInitialGuessFn *, void *);
531 PETSC_EXTERN PetscErrorCode SNESSetPicard(SNES, Vec, SNESFunctionFn *, Mat, Mat, SNESJacobianFn *, void *);
532 PETSC_EXTERN PetscErrorCode SNESGetPicard(SNES, Vec *, SNESFunctionFn **, Mat *, Mat *, SNESJacobianFn **, void **);
533 PETSC_EXTERN SNESFunctionFn SNESPicardComputeFunction;
534 PETSC_EXTERN SNESFunctionFn SNESPicardComputeMFFunction;
535 PETSC_EXTERN SNESJacobianFn SNESPicardComputeJacobian;
536 
537 PETSC_EXTERN PetscErrorCode SNESSetObjective(SNES, SNESObjectiveFn *, void *);
538 PETSC_EXTERN PetscErrorCode SNESGetObjective(SNES, SNESObjectiveFn **, void **);
539 PETSC_EXTERN PetscErrorCode SNESComputeObjective(SNES, Vec, PetscReal *);
540 
541 PETSC_EXTERN PetscErrorCode SNESSetUpdate(SNES, SNESUpdateFn *);
542 
543 /*E
544    SNESNormSchedule - Frequency with which the norm is computed during a nonliner solve
545 
546    Values:
547 +   `SNES_NORM_DEFAULT`            - use the default behavior for the current `SNESType`
548 .   `SNES_NORM_NONE`               - avoid all norm computations
549 .   `SNES_NORM_ALWAYS`             - compute the norms whenever possible
550 .   `SNES_NORM_INITIAL_ONLY`       - compute the norm only when the algorithm starts
551 .   `SNES_NORM_FINAL_ONLY`         - compute the norm only when the algorithm finishes
552 -   `SNES_NORM_INITIAL_FINAL_ONLY` - compute the norm at the start and end of the algorithm
553 
554    Level: advanced
555 
556    Notes:
557    Support for these is highly dependent on the solver.
558 
559    Some options limit the convergence tests that can be used.
560 
561    The `SNES_NORM_NONE` option is most commonly used when the nonlinear solver is being used as a smoother, for example for `SNESFAS`
562 
563    This is primarily used to turn off extra norm and function computation
564    when the solvers are composed.
565 
566 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
567           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
568 E*/
569 typedef enum {
570   SNES_NORM_DEFAULT            = -1,
571   SNES_NORM_NONE               = 0,
572   SNES_NORM_ALWAYS             = 1,
573   SNES_NORM_INITIAL_ONLY       = 2,
574   SNES_NORM_FINAL_ONLY         = 3,
575   SNES_NORM_INITIAL_FINAL_ONLY = 4
576 } SNESNormSchedule;
577 PETSC_EXTERN const char *const *const SNESNormSchedules;
578 
579 /*MC
580    SNES_NORM_NONE - Don't compute function and its L2 norm when possible
581 
582    Level: advanced
583 
584    Note:
585    This is most useful for stationary solvers with a fixed number of iterations used as smoothers.
586 
587 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_DEFAULT`
588 M*/
589 
590 /*MC
591    SNES_NORM_ALWAYS - Compute the function and its L2 norm at each iteration.
592 
593    Level: advanced
594 
595    Note:
596    Most solvers will use this no matter what norm type is passed to them.
597 
598 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_NONE`
599 M*/
600 
601 /*MC
602    SNES_NORM_INITIAL_ONLY - Compute the function and its L2 at iteration 0, but do not update it.
603 
604    Level: advanced
605 
606    Notes:
607    This method is useful in composed methods, when a true solution might actually be found before `SNESSolve()` is called.
608    This option enables the solve to abort on the zeroth iteration if this is the case.
609 
610    For solvers that require the computation of the L2 norm of the function as part of the method, this merely cancels
611    the norm computation at the last iteration (if possible).
612 
613 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_FINAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
614 M*/
615 
616 /*MC
617    SNES_NORM_FINAL_ONLY - Compute the function and its L2 norm on only the final iteration.
618 
619    Level: advanced
620 
621    Note:
622    For solvers that require the computation of the L2 norm of the function as part of the method, behaves
623    exactly as `SNES_NORM_DEFAULT`.  This method is useful when the function is gotten after `SNESSolve()` and
624    used in subsequent computation for methods that do not need the norm computed during the rest of the
625    solution procedure.
626 
627 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_INITIAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
628 M*/
629 
630 /*MC
631    SNES_NORM_INITIAL_FINAL_ONLY - Compute the function and its L2 norm on only the initial and final iterations.
632 
633    Level: advanced
634 
635    Note:
636    This method combines the benefits of `SNES_NORM_INITIAL_ONLY` and `SNES_NORM_FINAL_ONLY`.
637 
638 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_SNES_NORM_INITIAL_ONLY`, `SNES_NORM_FINAL_ONLY`
639 M*/
640 
641 PETSC_EXTERN PetscErrorCode SNESSetNormSchedule(SNES, SNESNormSchedule);
642 PETSC_EXTERN PetscErrorCode SNESGetNormSchedule(SNES, SNESNormSchedule *);
643 PETSC_EXTERN PetscErrorCode SNESSetFunctionNorm(SNES, PetscReal);
644 PETSC_EXTERN PetscErrorCode SNESGetFunctionNorm(SNES, PetscReal *);
645 PETSC_EXTERN PetscErrorCode SNESGetUpdateNorm(SNES, PetscReal *);
646 PETSC_EXTERN PetscErrorCode SNESGetSolutionNorm(SNES, PetscReal *);
647 
648 /*E
649    SNESFunctionType - Type of function computed
650 
651    Values:
652 +  `SNES_FUNCTION_DEFAULT`          - the default behavior for the current `SNESType`
653 .  `SNES_FUNCTION_UNPRECONDITIONED` - the original function provided
654 -  `SNES_FUNCTION_PRECONDITIONED`   - the modification of the function by the preconditioner
655 
656    Level: advanced
657 
658    Note:
659    Support for these is dependent on the solver.
660 
661 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
662           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
663 E*/
664 typedef enum {
665   SNES_FUNCTION_DEFAULT          = -1,
666   SNES_FUNCTION_UNPRECONDITIONED = 0,
667   SNES_FUNCTION_PRECONDITIONED   = 1
668 } SNESFunctionType;
669 PETSC_EXTERN const char *const *const SNESFunctionTypes;
670 
671 PETSC_EXTERN PetscErrorCode SNESSetFunctionType(SNES, SNESFunctionType);
672 PETSC_EXTERN PetscErrorCode SNESGetFunctionType(SNES, SNESFunctionType *);
673 
674 PETSC_EXTERN PetscErrorCode SNESSetNGS(SNES, SNESNGSFn *, void *);
675 PETSC_EXTERN PetscErrorCode SNESGetNGS(SNES, SNESNGSFn **, void **);
676 PETSC_EXTERN PetscErrorCode SNESComputeNGS(SNES, Vec, Vec);
677 
678 PETSC_EXTERN PetscErrorCode SNESNGSSetSweeps(SNES, PetscInt);
679 PETSC_EXTERN PetscErrorCode SNESNGSGetSweeps(SNES, PetscInt *);
680 PETSC_EXTERN PetscErrorCode SNESNGSSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt);
681 PETSC_EXTERN PetscErrorCode SNESNGSGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
682 
683 PETSC_EXTERN PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES, PetscBool);
684 PETSC_EXTERN PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES, PetscBool *);
685 
686 PETSC_EXTERN PetscErrorCode SNESShellGetContext(SNES, void *);
687 PETSC_EXTERN PetscErrorCode SNESShellSetContext(SNES, void *);
688 PETSC_EXTERN PetscErrorCode SNESShellSetSolve(SNES, PetscErrorCode (*)(SNES, Vec));
689 
690 /* --------- Routines specifically for line search methods --------------- */
691 
692 /*S
693    SNESLineSearch - Abstract PETSc object that manages line-search operations for nonlinear solvers
694 
695    Level: beginner
696 
697 .seealso: [](ch_snes), `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetType()`, `SNES`
698 S*/
699 typedef struct _p_LineSearch *SNESLineSearch;
700 
701 /*J
702    SNESLineSearchType - String with the name of a PETSc line search method `SNESLineSearch`
703 
704    Values:
705 +  `SNESLINESEARCHBASIC`   - (or equivalently `SNESLINESEARCHNONE`) Simple damping line search, defaults to using the full Newton step
706 .  `SNESLINESEARCHBT`      - Backtracking line search over the L2 norm of the function
707 .  `SNESLINESEARCHL2`      - Secant line search over the L2 norm of the function
708 .  `SNESLINESEARCHCP`      - Critical point secant line search assuming F(x) = grad G(x) for some unknown G(x)
709 .  `SNESLINESEARCHNLEQERR` - Affine-covariant error-oriented linesearch
710 -  `SNESLINESEARCHSHELL`   - User provided `SNESLineSearch` implementation
711 
712    Level: beginner
713 
714 .seealso: [](ch_snes), `SNESLineSearch`, `SNESLineSearchSetType()`, `SNES`
715 J*/
716 typedef const char *SNESLineSearchType;
717 #define SNESLINESEARCHBT        "bt"
718 #define SNESLINESEARCHNLEQERR   "nleqerr"
719 #define SNESLINESEARCHBASIC     "basic"
720 #define SNESLINESEARCHNONE      "none"
721 #define SNESLINESEARCHL2        "l2"
722 #define SNESLINESEARCHCP        "cp"
723 #define SNESLINESEARCHSHELL     "shell"
724 #define SNESLINESEARCHNCGLINEAR "ncglinear"
725 
726 PETSC_EXTERN PetscFunctionList SNESList;
727 PETSC_EXTERN PetscClassId      SNESLINESEARCH_CLASSID;
728 PETSC_EXTERN PetscFunctionList SNESLineSearchList;
729 
730 #define SNES_LINESEARCH_ORDER_LINEAR    1
731 #define SNES_LINESEARCH_ORDER_QUADRATIC 2
732 #define SNES_LINESEARCH_ORDER_CUBIC     3
733 
734 /*S
735   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that projects a vector onto the VI bounds, passed to `SNESLineSearchSetVIFunctions()`
736 
737   Calling Sequence:
738 + snes  - `SNES` context
739 - u     - the vector to project to the bounds
740 
741   Level: advanced
742 
743   Note:
744   The deprecated `SNESLineSearchVIProjectFunc` still works as a replacement for `SNESLineSearchVIProjectFn` *.
745 
746 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
747 S*/
748 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVIProjectFn)(SNES snes, Vec u);
749 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVIProjectFn *SNESLineSearchVIProjectFunc; // deprecated
750 
751 /*S
752   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that computes the norm of the active set variables in a vector in a VI solve,
753   passed to `SNESLineSearchSetVIFunctions()`
754 
755   Calling Sequence:
756 + snes  - `SNES` context
757 . f     - the vector to compute the norm of
758 . u     - the current solution, entries that are on the VI bounds are ignored
759 - fnorm - the resulting norm
760 
761   Level: advanced
762 
763   Note:
764   The deprecated `SNESLineSearchVINormFunc` still works as a replacement for `SNESLineSearchVINormFn` *.
765 
766 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
767 S*/
768 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVINormFn)(SNES snes, Vec f, Vec u, PetscReal *fnorm);
769 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVINormFn *SNESLineSearchVINormFunc; // deprecated
770 
771 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchApplyFn)(SNESLineSearch);
772 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchApplyFn *SNESLineSearchApplyFunc; // deprecated
773 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchShellApplyFn)(SNESLineSearch, void *);
774 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchShellApplyFn *SNESLineSearchUserFunc; // deprecated
775 
776 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate(MPI_Comm, SNESLineSearch *);
777 PETSC_EXTERN PetscErrorCode SNESLineSearchReset(SNESLineSearch);
778 PETSC_EXTERN PetscErrorCode SNESLineSearchView(SNESLineSearch, PetscViewer);
779 PETSC_EXTERN PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *);
780 PETSC_EXTERN PetscErrorCode SNESLineSearchGetType(SNESLineSearch, SNESLineSearchType *);
781 PETSC_EXTERN PetscErrorCode SNESLineSearchSetType(SNESLineSearch, SNESLineSearchType);
782 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch);
783 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch, PetscErrorCode (*)(SNES, Vec, Vec));
784 PETSC_EXTERN PetscErrorCode SNESLineSearchSetUp(SNESLineSearch);
785 PETSC_EXTERN PetscErrorCode SNESLineSearchApply(SNESLineSearch, Vec, Vec, PetscReal *, Vec);
786 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch, Vec, Vec, PetscBool *);
787 PETSC_EXTERN PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *);
788 PETSC_EXTERN PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch, PetscInt);
789 
790 /* set the functions for precheck and postcheck */
791 
792 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void *ctx);
793 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
794 
795 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void **ctx);
796 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
797 
798 /* set the functions for VI-specific line search operations */
799 
800 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn *, SNESLineSearchVINormFn *);
801 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn **, SNESLineSearchVINormFn **);
802 
803 /* pointers to the associated SNES in order to be able to get the function evaluation out */
804 PETSC_EXTERN PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch, SNES);
805 PETSC_EXTERN PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch, SNES *);
806 
807 /* set and get the parameters and vectors */
808 PETSC_EXTERN PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
809 PETSC_EXTERN PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscInt);
810 
811 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch, Vec, Vec, PetscBool *, void *);
812 
813 PETSC_EXTERN PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch, PetscReal *);
814 PETSC_EXTERN PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch, PetscReal);
815 
816 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch, PetscReal *);
817 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch, PetscReal);
818 
819 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch, PetscInt *order);
820 PETSC_EXTERN PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch, PetscInt order);
821 
822 /*E
823     SNESLineSearchReason - indication if the line search has succeeded or failed and why
824 
825   Values:
826 +  `SNES_LINESEARCH_SUCCEEDED`       - the line search succeeded
827 .  `SNES_LINESEARCH_FAILED_NANORINF` - a not a number of infinity appeared in the computions
828 .  `SNES_LINESEARCH_FAILED_DOMAIN`   - the function was evaluated outside of its domain, see `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
829 .  `SNES_LINESEARCH_FAILED_REDUCT`   - the linear search failed to get the requested decrease in its norm or objective
830 .  `SNES_LINESEARCH_FAILED_USER`     - used by `SNESLINESEARCHNLEQERR` to indicate the user changed the search direction inappropriately
831 -  `SNES_LINESEARCH_FAILED_FUNCTION` - indicates the maximum number of function evaluations allowed has been surpassed, `SNESConvergedReason` is also
832                                        set to `SNES_DIVERGED_FUNCTION_COUNT`
833 
834    Level: intermediate
835 
836    Developer Note:
837    Some of these reasons overlap with values of `SNESConvergedReason`
838 
839 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`,
840           `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
841 E*/
842 typedef enum {
843   SNES_LINESEARCH_SUCCEEDED,
844   SNES_LINESEARCH_FAILED_NANORINF,
845   SNES_LINESEARCH_FAILED_DOMAIN,
846   SNES_LINESEARCH_FAILED_REDUCT, /* INSUFFICIENT REDUCTION */
847   SNES_LINESEARCH_FAILED_USER,
848   SNES_LINESEARCH_FAILED_FUNCTION
849 } SNESLineSearchReason;
850 
851 PETSC_EXTERN PetscErrorCode SNESLineSearchGetReason(SNESLineSearch, SNESLineSearchReason *);
852 PETSC_EXTERN PetscErrorCode SNESLineSearchSetReason(SNESLineSearch, SNESLineSearchReason);
853 
854 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch, Vec *, Vec *, Vec *, Vec *, Vec *);
855 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch, Vec, Vec, Vec, Vec, Vec);
856 
857 PETSC_EXTERN PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *);
858 PETSC_EXTERN PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch, PetscReal, PetscReal, PetscReal);
859 PETSC_EXTERN PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch);
860 PETSC_EXTERN PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch, PetscBool);
861 
862 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitor(SNESLineSearch);
863 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSet(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, void *), void *, PetscErrorCode (*)(void **));
864 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSetFromOptions(SNESLineSearch, const char[], const char[], const char[], PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *), PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *));
865 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorCancel(SNESLineSearch);
866 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch, PetscViewer);
867 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDefaultMonitor(SNESLineSearch, PetscViewer *);
868 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSolutionUpdate(SNESLineSearch, PetscViewerAndFormat *);
869 
870 PETSC_EXTERN PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch, const char prefix[]);
871 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch, const char *prefix[]);
872 
873 /* Shell interface functions */
874 PETSC_EXTERN PetscErrorCode SNESLineSearchShellSetApply(SNESLineSearch, SNESLineSearchShellApplyFn, void *);
875 PETSC_EXTERN PetscErrorCode SNESLineSearchShellGetApply(SNESLineSearch, SNESLineSearchShellApplyFn **, void **);
876 
877 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellSetApply()", ) static inline PetscErrorCode SNESLineSearchShellSetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc f, void *ctx)
878 {
879   return SNESLineSearchShellSetApply(ls, f, ctx);
880 }
881 
882 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellGetApply()", ) static inline PetscErrorCode SNESLineSearchShellGetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc *f, void **ctx)
883 {
884   return SNESLineSearchShellGetApply(ls, f, ctx);
885 }
886 
887 /* BT interface functions */
888 PETSC_EXTERN PetscErrorCode SNESLineSearchBTSetAlpha(SNESLineSearch, PetscReal);
889 PETSC_EXTERN PetscErrorCode SNESLineSearchBTGetAlpha(SNESLineSearch, PetscReal *);
890 
891 /*register line search types */
892 PETSC_EXTERN PetscErrorCode SNESLineSearchRegister(const char[], PetscErrorCode (*)(SNESLineSearch));
893 
894 /* Routines for VI solver */
895 PETSC_EXTERN PetscErrorCode SNESVISetVariableBounds(SNES, Vec, Vec);
896 PETSC_EXTERN PetscErrorCode SNESVIGetVariableBounds(SNES, Vec *, Vec *);
897 PETSC_EXTERN PetscErrorCode SNESVISetComputeVariableBounds(SNES, PetscErrorCode (*)(SNES, Vec, Vec));
898 PETSC_EXTERN PetscErrorCode SNESVIGetInactiveSet(SNES, IS *);
899 PETSC_EXTERN PetscErrorCode SNESVIGetActiveSetIS(SNES, Vec, Vec, IS *);
900 PETSC_EXTERN PetscErrorCode SNESVIComputeInactiveSetFnorm(SNES, Vec, Vec, PetscReal *);
901 PETSC_EXTERN PetscErrorCode SNESVISetRedundancyCheck(SNES, PetscErrorCode (*)(SNES, IS, IS *, void *), void *);
902 PETSC_EXTERN PetscErrorCode SNESVIComputeMeritFunction(Vec, PetscReal *, PetscReal *);
903 PETSC_EXTERN PetscErrorCode SNESVIComputeFunction(SNES, Vec, Vec, void *);
904 PETSC_EXTERN PetscErrorCode DMSetVI(DM, IS);
905 PETSC_EXTERN PetscErrorCode DMDestroyVI(DM);
906 
907 PETSC_EXTERN PetscErrorCode SNESTestLocalMin(SNES);
908 
909 /* Should this routine be private? */
910 PETSC_EXTERN PetscErrorCode SNESComputeJacobian(SNES, Vec, Mat, Mat);
911 PETSC_EXTERN PetscErrorCode SNESTestJacobian(SNES);
912 PETSC_EXTERN PetscErrorCode SNESTestFunction(SNES);
913 
914 PETSC_EXTERN PetscErrorCode SNESSetDM(SNES, DM);
915 PETSC_EXTERN PetscErrorCode SNESGetDM(SNES, DM *);
916 PETSC_EXTERN PetscErrorCode SNESSetNPC(SNES, SNES);
917 PETSC_EXTERN PetscErrorCode SNESGetNPC(SNES, SNES *);
918 PETSC_EXTERN PetscErrorCode SNESHasNPC(SNES, PetscBool *);
919 PETSC_EXTERN PetscErrorCode SNESApplyNPC(SNES, Vec, Vec, Vec);
920 PETSC_EXTERN PetscErrorCode SNESGetNPCFunction(SNES, Vec, PetscReal *);
921 PETSC_EXTERN PetscErrorCode SNESComputeFunctionDefaultNPC(SNES, Vec, Vec);
922 PETSC_EXTERN PetscErrorCode SNESSetNPCSide(SNES, PCSide);
923 PETSC_EXTERN PetscErrorCode SNESGetNPCSide(SNES, PCSide *);
924 PETSC_EXTERN PetscErrorCode SNESSetLineSearch(SNES, SNESLineSearch);
925 PETSC_EXTERN PetscErrorCode SNESGetLineSearch(SNES, SNESLineSearch *);
926 
927 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESGetLineSearch()", ) static inline PetscErrorCode SNESGetSNESLineSearch(SNES snes, SNESLineSearch *ls)
928 {
929   return SNESGetLineSearch(snes, ls);
930 }
931 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESSetLineSearch()", ) static inline PetscErrorCode SNESSetSNESLineSearch(SNES snes, SNESLineSearch ls)
932 {
933   return SNESSetLineSearch(snes, ls);
934 }
935 
936 PETSC_EXTERN PetscErrorCode SNESSetUpMatrices(SNES);
937 PETSC_EXTERN PetscErrorCode DMSNESSetFunction(DM, SNESFunctionFn *, void *);
938 PETSC_EXTERN PetscErrorCode DMSNESGetFunction(DM, SNESFunctionFn **, void **);
939 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionContextDestroy(DM, PetscErrorCode (*)(void *));
940 PETSC_EXTERN PetscErrorCode DMSNESSetMFFunction(DM, SNESFunctionFn *, void *);
941 PETSC_EXTERN PetscErrorCode DMSNESSetNGS(DM, SNESNGSFn *, void *);
942 PETSC_EXTERN PetscErrorCode DMSNESGetNGS(DM, SNESNGSFn **, void **);
943 PETSC_EXTERN PetscErrorCode DMSNESSetJacobian(DM, SNESJacobianFn *, void *);
944 PETSC_EXTERN PetscErrorCode DMSNESGetJacobian(DM, SNESJacobianFn **, void **);
945 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianContextDestroy(DM, PetscErrorCode (*)(void *));
946 PETSC_EXTERN PetscErrorCode DMSNESSetPicard(DM, SNESFunctionFn *, SNESJacobianFn *, void *);
947 PETSC_EXTERN PetscErrorCode DMSNESGetPicard(DM, SNESFunctionFn **, SNESJacobianFn **, void **);
948 PETSC_EXTERN PetscErrorCode DMSNESSetObjective(DM, SNESObjectiveFn *, void *);
949 PETSC_EXTERN PetscErrorCode DMSNESGetObjective(DM, SNESObjectiveFn **, void **);
950 PETSC_EXTERN PetscErrorCode DMCopyDMSNES(DM, DM);
951 
952 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionFn)(DMDALocalInfo *, void *, void *, void *);
953 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianFn)(DMDALocalInfo *, void *, Mat, Mat, void *);
954 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveFn)(DMDALocalInfo *, void *, PetscReal *, void *);
955 
956 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionVecFn)(DMDALocalInfo *, Vec, Vec, void *);
957 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianVecFn)(DMDALocalInfo *, Vec, Mat, Mat, void *);
958 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveVecFn)(DMDALocalInfo *, Vec, PetscReal *, void *);
959 
960 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocal(DM, InsertMode, DMDASNESFunctionFn *, void *);
961 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocal(DM, DMDASNESJacobianFn *, void *);
962 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocal(DM, DMDASNESObjectiveFn *, void *);
963 PETSC_EXTERN PetscErrorCode DMDASNESSetPicardLocal(DM, InsertMode, DMDASNESFunctionFn *, DMDASNESJacobianFn, void *);
964 
965 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocalVec(DM, InsertMode, DMDASNESFunctionVecFn *, void *);
966 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocalVec(DM, DMDASNESJacobianVecFn *, void *);
967 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocalVec(DM, DMDASNESObjectiveVecFn *, void *);
968 
969 PETSC_EXTERN PetscErrorCode DMSNESSetBoundaryLocal(DM, PetscErrorCode (*)(DM, Vec, void *), void *);
970 PETSC_EXTERN PetscErrorCode DMSNESSetObjectiveLocal(DM, PetscErrorCode (*)(DM, Vec, PetscReal *, void *), void *);
971 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionLocal(DM, PetscErrorCode (*)(DM, Vec, Vec, void *), void *);
972 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianLocal(DM, PetscErrorCode (*)(DM, Vec, Mat, Mat, void *), void *);
973 PETSC_EXTERN PetscErrorCode DMSNESGetBoundaryLocal(DM, PetscErrorCode (**)(DM, Vec, void *), void **);
974 PETSC_EXTERN PetscErrorCode DMSNESGetObjectiveLocal(DM, PetscErrorCode (**)(DM, Vec, PetscReal *, void *), void **);
975 PETSC_EXTERN PetscErrorCode DMSNESGetFunctionLocal(DM, PetscErrorCode (**)(DM, Vec, Vec, void *), void **);
976 PETSC_EXTERN PetscErrorCode DMSNESGetJacobianLocal(DM, PetscErrorCode (**)(DM, Vec, Mat, Mat, void *), void **);
977 
978 /* Routines for Multiblock solver */
979 PETSC_EXTERN PetscErrorCode SNESMultiblockSetFields(SNES, const char[], PetscInt, const PetscInt *);
980 PETSC_EXTERN PetscErrorCode SNESMultiblockSetIS(SNES, const char[], IS);
981 PETSC_EXTERN PetscErrorCode SNESMultiblockSetBlockSize(SNES, PetscInt);
982 PETSC_EXTERN PetscErrorCode SNESMultiblockSetType(SNES, PCCompositeType);
983 PETSC_EXTERN PetscErrorCode SNESMultiblockGetSubSNES(SNES, PetscInt *, SNES *[]);
984 
985 /*J
986    SNESMSType - String with the name of a PETSc `SNESMS` method.
987 
988    Level: intermediate
989 
990 .seealso: [](ch_snes), `SNESMS`, `SNESMSGetType()`, `SNESMSSetType()`, `SNES`
991 J*/
992 typedef const char *SNESMSType;
993 #define SNESMSM62       "m62"
994 #define SNESMSEULER     "euler"
995 #define SNESMSJAMESON83 "jameson83"
996 #define SNESMSVLTP11    "vltp11"
997 #define SNESMSVLTP21    "vltp21"
998 #define SNESMSVLTP31    "vltp31"
999 #define SNESMSVLTP41    "vltp41"
1000 #define SNESMSVLTP51    "vltp51"
1001 #define SNESMSVLTP61    "vltp61"
1002 
1003 PETSC_EXTERN PetscErrorCode SNESMSRegister(SNESMSType, PetscInt, PetscInt, PetscReal, const PetscReal[], const PetscReal[], const PetscReal[]);
1004 PETSC_EXTERN PetscErrorCode SNESMSRegisterAll(void);
1005 PETSC_EXTERN PetscErrorCode SNESMSGetType(SNES, SNESMSType *);
1006 PETSC_EXTERN PetscErrorCode SNESMSSetType(SNES, SNESMSType);
1007 PETSC_EXTERN PetscErrorCode SNESMSGetDamping(SNES, PetscReal *);
1008 PETSC_EXTERN PetscErrorCode SNESMSSetDamping(SNES, PetscReal);
1009 PETSC_EXTERN PetscErrorCode SNESMSFinalizePackage(void);
1010 PETSC_EXTERN PetscErrorCode SNESMSInitializePackage(void);
1011 PETSC_EXTERN PetscErrorCode SNESMSRegisterDestroy(void);
1012 
1013 /*MC
1014    SNESNGMRESRestartType - the restart approach used by `SNESNGMRES`
1015 
1016   Values:
1017 +   `SNES_NGMRES_RESTART_NONE`       - never restart
1018 .   `SNES_NGMRES_RESTART_DIFFERENCE` - restart based upon difference criteria
1019 -   `SNES_NGMRES_RESTART_PERIODIC`   - restart after a fixed number of iterations
1020 
1021   Options Database Keys:
1022 + -snes_ngmres_restart_type <difference,periodic,none> - set the restart type
1023 - -snes_ngmres_restart <30>                            - sets the number of iterations before restart for periodic
1024 
1025    Level: intermediate
1026 
1027 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1028           `SNESNGMRESGetRestartType()`, `SNESNGMRESSelectType`
1029 M*/
1030 typedef enum {
1031   SNES_NGMRES_RESTART_NONE       = 0,
1032   SNES_NGMRES_RESTART_PERIODIC   = 1,
1033   SNES_NGMRES_RESTART_DIFFERENCE = 2
1034 } SNESNGMRESRestartType;
1035 PETSC_EXTERN const char *const SNESNGMRESRestartTypes[];
1036 
1037 /*MC
1038    SNESNGMRESSelectType - the approach used by `SNESNGMRES` to determine how the candidate solution and
1039   combined solution are used to create the next iterate.
1040 
1041    Values:
1042 +   `SNES_NGMRES_SELECT_NONE`       - choose the combined solution all the time
1043 .   `SNES_NGMRES_SELECT_DIFFERENCE` - choose based upon the selection criteria
1044 -   `SNES_NGMRES_SELECT_LINESEARCH` - choose based upon line search combination
1045 
1046   Options Database Key:
1047 . -snes_ngmres_select_type<difference,none,linesearch> - select type
1048 
1049    Level: intermediate
1050 
1051 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1052           `SNESNGMRESGetRestartType()`, `SNESNGMRESRestartType`
1053 M*/
1054 typedef enum {
1055   SNES_NGMRES_SELECT_NONE       = 0,
1056   SNES_NGMRES_SELECT_DIFFERENCE = 1,
1057   SNES_NGMRES_SELECT_LINESEARCH = 2
1058 } SNESNGMRESSelectType;
1059 PETSC_EXTERN const char *const SNESNGMRESSelectTypes[];
1060 
1061 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartType(SNES, SNESNGMRESRestartType);
1062 PETSC_EXTERN PetscErrorCode SNESNGMRESSetSelectType(SNES, SNESNGMRESSelectType);
1063 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartFmRise(SNES, PetscBool);
1064 PETSC_EXTERN PetscErrorCode SNESNGMRESGetRestartFmRise(SNES, PetscBool *);
1065 
1066 /*MC
1067    SNESNCGType - the conjugate update approach for `SNESNCG`
1068 
1069    Values:
1070 +   `SNES_NCG_FR`  - Fletcher-Reeves update
1071 .   `SNES_NCG_PRP` - Polak-Ribiere-Polyak update, the default and the only one that tolerates generalized search directions
1072 .   `SNES_NCG_HS`  - Hestenes-Steifel update
1073 .   `SNES_NCG_DY`  - Dai-Yuan update
1074 -   `SNES_NCG_CD`  - Conjugate Descent update
1075 
1076   Options Database Key:
1077 . -snes_ncg_type<fr,prp,hs,dy,cd> - select type
1078 
1079    Level: intermediate
1080 
1081 .seealso: `SNES, `SNESNCG`, `SNESNCGSetType()`
1082 M*/
1083 typedef enum {
1084   SNES_NCG_FR  = 0,
1085   SNES_NCG_PRP = 1,
1086   SNES_NCG_HS  = 2,
1087   SNES_NCG_DY  = 3,
1088   SNES_NCG_CD  = 4
1089 } SNESNCGType;
1090 PETSC_EXTERN const char *const SNESNCGTypes[];
1091 
1092 PETSC_EXTERN PetscErrorCode SNESNCGSetType(SNES, SNESNCGType);
1093 
1094 /*MC
1095    SNESQNScaleType - the scaling type used by `SNESQN`
1096 
1097    Values:
1098 +   `SNES_QN_SCALE_NONE`     - don't scale the problem
1099 .   `SNES_QN_SCALE_SCALAR`   - use Shanno scaling
1100 .   `SNES_QN_SCALE_DIAGONAL` - scale with a diagonalized BFGS formula (see Gilbert and Lemarechal 1989), available
1101 -   `SNES_QN_SCALE_JACOBIAN` - scale by solving a linear system coming from the Jacobian you provided with `SNESSetJacobian()`
1102                                computed at the first iteration of `SNESQN` and at ever restart.
1103 
1104     Options Database Key:
1105 . -snes_qn_scale_type <diagonal,none,scalar,jacobian> - Scaling type
1106 
1107    Level: intermediate
1108 
1109 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNRestartType`
1110 M*/
1111 typedef enum {
1112   SNES_QN_SCALE_DEFAULT  = 0,
1113   SNES_QN_SCALE_NONE     = 1,
1114   SNES_QN_SCALE_SCALAR   = 2,
1115   SNES_QN_SCALE_DIAGONAL = 3,
1116   SNES_QN_SCALE_JACOBIAN = 4
1117 } SNESQNScaleType;
1118 PETSC_EXTERN const char *const SNESQNScaleTypes[];
1119 
1120 /*MC
1121    SNESQNRestartType - the restart approached used by `SNESQN`
1122 
1123    Values:
1124 +   `SNES_QN_RESTART_NONE`     - never restart
1125 .   `SNES_QN_RESTART_POWELL`   - restart based upon descent criteria
1126 -   `SNES_QN_RESTART_PERIODIC` - restart after a fixed number of iterations
1127 
1128   Options Database Keys:
1129 + -snes_qn_restart_type <powell,periodic,none> - set the restart type
1130 - -snes_qn_m <m>                               - sets the number of stored updates and the restart period for periodic
1131 
1132    Level: intermediate
1133 
1134 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNScaleType`
1135 M*/
1136 typedef enum {
1137   SNES_QN_RESTART_DEFAULT  = 0,
1138   SNES_QN_RESTART_NONE     = 1,
1139   SNES_QN_RESTART_POWELL   = 2,
1140   SNES_QN_RESTART_PERIODIC = 3
1141 } SNESQNRestartType;
1142 PETSC_EXTERN const char *const SNESQNRestartTypes[];
1143 
1144 /*MC
1145    SNESQNType - the type used by `SNESQN`
1146 
1147   Values:
1148 +   `SNES_QN_LBFGS`      - LBFGS variant
1149 .   `SNES_QN_BROYDEN`    - Broyden variant
1150 -   `SNES_QN_BADBROYDEN` - Bad Broyden variant
1151 
1152   Options Database Key:
1153 . -snes_qn_type <lbfgs,broyden,badbroyden> - quasi-Newton type
1154 
1155    Level: intermediate
1156 
1157 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNSetType()`, `SNESQNScaleType`, `SNESQNRestartType`, `SNESQNSetRestartType()`
1158 M*/
1159 typedef enum {
1160   SNES_QN_LBFGS      = 0,
1161   SNES_QN_BROYDEN    = 1,
1162   SNES_QN_BADBROYDEN = 2
1163 } SNESQNType;
1164 PETSC_EXTERN const char *const SNESQNTypes[];
1165 
1166 PETSC_EXTERN PetscErrorCode SNESQNSetType(SNES, SNESQNType);
1167 PETSC_EXTERN PetscErrorCode SNESQNSetScaleType(SNES, SNESQNScaleType);
1168 PETSC_EXTERN PetscErrorCode SNESQNSetRestartType(SNES, SNESQNRestartType);
1169 
1170 PETSC_EXTERN PetscErrorCode SNESNASMGetType(SNES, PCASMType *);
1171 PETSC_EXTERN PetscErrorCode SNESNASMSetType(SNES, PCASMType);
1172 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomains(SNES, PetscInt *, SNES **, VecScatter **, VecScatter **, VecScatter **);
1173 PETSC_EXTERN PetscErrorCode SNESNASMSetSubdomains(SNES, PetscInt, SNES *, VecScatter *, VecScatter *, VecScatter *);
1174 PETSC_EXTERN PetscErrorCode SNESNASMSetDamping(SNES, PetscReal);
1175 PETSC_EXTERN PetscErrorCode SNESNASMGetDamping(SNES, PetscReal *);
1176 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomainVecs(SNES, PetscInt *, Vec **, Vec **, Vec **, Vec **);
1177 PETSC_EXTERN PetscErrorCode SNESNASMSetComputeFinalJacobian(SNES, PetscBool);
1178 PETSC_EXTERN PetscErrorCode SNESNASMGetSNES(SNES, PetscInt, SNES *);
1179 PETSC_EXTERN PetscErrorCode SNESNASMGetNumber(SNES, PetscInt *);
1180 PETSC_EXTERN PetscErrorCode SNESNASMSetWeight(SNES, Vec);
1181 
1182 /*E
1183   SNESCompositeType - Determines how two or more preconditioners are composed with the `SNESType` of `SNESCOMPOSITE`
1184 
1185   Values:
1186 + `SNES_COMPOSITE_ADDITIVE`        - results from application of all preconditioners are added together
1187 . `SNES_COMPOSITE_MULTIPLICATIVE`  - preconditioners are applied sequentially to the residual freshly
1188                                      computed after the previous preconditioner application
1189 - `SNES_COMPOSITE_ADDITIVEOPTIMAL` - uses a linear combination of the solutions obtained with each preconditioner that approximately minimize the function
1190                                      value at the new iteration.
1191 
1192    Level: beginner
1193 
1194 .seealso: [](sec_pc), `PCCOMPOSITE`, `PCFIELDSPLIT`, `PC`, `PCCompositeSetType()`, `PCCompositeType`
1195 E*/
1196 typedef enum {
1197   SNES_COMPOSITE_ADDITIVE,
1198   SNES_COMPOSITE_MULTIPLICATIVE,
1199   SNES_COMPOSITE_ADDITIVEOPTIMAL
1200 } SNESCompositeType;
1201 PETSC_EXTERN const char *const SNESCompositeTypes[];
1202 
1203 PETSC_EXTERN PetscErrorCode SNESCompositeSetType(SNES, SNESCompositeType);
1204 PETSC_EXTERN PetscErrorCode SNESCompositeAddSNES(SNES, SNESType);
1205 PETSC_EXTERN PetscErrorCode SNESCompositeGetSNES(SNES, PetscInt, SNES *);
1206 PETSC_EXTERN PetscErrorCode SNESCompositeGetNumber(SNES, PetscInt *);
1207 PETSC_EXTERN PetscErrorCode SNESCompositeSetDamping(SNES, PetscInt, PetscReal);
1208 
1209 PETSC_EXTERN PetscErrorCode SNESPatchSetDiscretisationInfo(SNES, PetscInt, DM *, PetscInt *, PetscInt *, const PetscInt **, const PetscInt *, PetscInt, const PetscInt *, PetscInt, const PetscInt *);
1210 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeOperator(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Mat, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1211 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeFunction(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Vec, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1212 PETSC_EXTERN PetscErrorCode SNESPatchSetConstructType(SNES, PCPatchConstructType, PetscErrorCode (*func)(PC, PetscInt *, IS **, IS *, void *), void *);
1213 PETSC_EXTERN PetscErrorCode SNESPatchSetCellNumbering(SNES, PetscSection);
1214 
1215 /*E
1216     SNESFASType - Determines the type of nonlinear multigrid method that is run.
1217 
1218    Values:
1219 +  `SNES_FAS_MULTIPLICATIVE` (default) - traditional V or W cycle as determined by `SNESFASSetCycles()`
1220 .  `SNES_FAS_ADDITIVE`                 - additive FAS cycle
1221 .  `SNES_FAS_FULL`                     - full FAS cycle
1222 -  `SNES_FAS_KASKADE`                  - Kaskade FAS cycle
1223 
1224    Level: beginner
1225 
1226 .seealso: [](ch_snes), `SNESFAS`, `PCMGSetType()`, `PCMGType`
1227 E*/
1228 typedef enum {
1229   SNES_FAS_MULTIPLICATIVE,
1230   SNES_FAS_ADDITIVE,
1231   SNES_FAS_FULL,
1232   SNES_FAS_KASKADE
1233 } SNESFASType;
1234 PETSC_EXTERN const char *const SNESFASTypes[];
1235 
1236 /* called on the finest level FAS instance*/
1237 PETSC_EXTERN PetscErrorCode SNESFASSetType(SNES, SNESFASType);
1238 PETSC_EXTERN PetscErrorCode SNESFASGetType(SNES, SNESFASType *);
1239 PETSC_EXTERN PetscErrorCode SNESFASSetLevels(SNES, PetscInt, MPI_Comm *);
1240 PETSC_EXTERN PetscErrorCode SNESFASGetLevels(SNES, PetscInt *);
1241 PETSC_EXTERN PetscErrorCode SNESFASGetCycleSNES(SNES, PetscInt, SNES *);
1242 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothUp(SNES, PetscInt);
1243 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothDown(SNES, PetscInt);
1244 PETSC_EXTERN PetscErrorCode SNESFASSetCycles(SNES, PetscInt);
1245 PETSC_EXTERN PetscErrorCode SNESFASSetMonitor(SNES, PetscViewerAndFormat *, PetscBool);
1246 PETSC_EXTERN PetscErrorCode SNESFASSetLog(SNES, PetscBool);
1247 
1248 PETSC_EXTERN PetscErrorCode SNESFASSetGalerkin(SNES, PetscBool);
1249 PETSC_EXTERN PetscErrorCode SNESFASGetGalerkin(SNES, PetscBool *);
1250 PETSC_EXTERN PetscErrorCode SNESFASGalerkinFunctionDefault(SNES, Vec, Vec, void *);
1251 
1252 /* called on any level -- "Cycle" FAS instance */
1253 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmoother(SNES, SNES *);
1254 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherUp(SNES, SNES *);
1255 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherDown(SNES, SNES *);
1256 PETSC_EXTERN PetscErrorCode SNESFASCycleGetCorrection(SNES, SNES *);
1257 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInterpolation(SNES, Mat *);
1258 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRestriction(SNES, Mat *);
1259 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInjection(SNES, Mat *);
1260 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRScale(SNES, Vec *);
1261 PETSC_EXTERN PetscErrorCode SNESFASCycleSetCycles(SNES, PetscInt);
1262 PETSC_EXTERN PetscErrorCode SNESFASCycleIsFine(SNES, PetscBool *);
1263 
1264 /* called on the (outer) finest level FAS to set/get parameters on any level instance */
1265 PETSC_EXTERN PetscErrorCode SNESFASSetInterpolation(SNES, PetscInt, Mat);
1266 PETSC_EXTERN PetscErrorCode SNESFASGetInterpolation(SNES, PetscInt, Mat *);
1267 PETSC_EXTERN PetscErrorCode SNESFASSetRestriction(SNES, PetscInt, Mat);
1268 PETSC_EXTERN PetscErrorCode SNESFASGetRestriction(SNES, PetscInt, Mat *);
1269 PETSC_EXTERN PetscErrorCode SNESFASSetInjection(SNES, PetscInt, Mat);
1270 PETSC_EXTERN PetscErrorCode SNESFASGetInjection(SNES, PetscInt, Mat *);
1271 PETSC_EXTERN PetscErrorCode SNESFASSetRScale(SNES, PetscInt, Vec);
1272 PETSC_EXTERN PetscErrorCode SNESFASGetRScale(SNES, PetscInt, Vec *);
1273 PETSC_EXTERN PetscErrorCode SNESFASSetContinuation(SNES, PetscBool);
1274 
1275 PETSC_EXTERN PetscErrorCode SNESFASGetSmoother(SNES, PetscInt, SNES *);
1276 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherUp(SNES, PetscInt, SNES *);
1277 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherDown(SNES, PetscInt, SNES *);
1278 PETSC_EXTERN PetscErrorCode SNESFASGetCoarseSolve(SNES, SNES *);
1279 
1280 /* parameters for full FAS */
1281 PETSC_EXTERN PetscErrorCode SNESFASFullSetDownSweep(SNES, PetscBool);
1282 PETSC_EXTERN PetscErrorCode SNESFASCreateCoarseVec(SNES, Vec *);
1283 PETSC_EXTERN PetscErrorCode SNESFASRestrict(SNES, Vec, Vec);
1284 PETSC_EXTERN PetscErrorCode SNESFASFullSetTotal(SNES, PetscBool);
1285 PETSC_EXTERN PetscErrorCode SNESFASFullGetTotal(SNES, PetscBool *);
1286 
1287 PETSC_EXTERN PetscErrorCode DMSNESCheckDiscretization(SNES, DM, PetscReal, Vec, PetscReal, PetscReal[]);
1288 PETSC_EXTERN PetscErrorCode DMSNESCheckResidual(SNES, DM, Vec, PetscReal, PetscReal *);
1289 PETSC_EXTERN PetscErrorCode DMSNESCheckJacobian(SNES, DM, Vec, PetscReal, PetscBool *, PetscReal *);
1290 PETSC_EXTERN PetscErrorCode DMSNESCheckFromOptions(SNES, Vec);
1291 PETSC_EXTERN PetscErrorCode DMSNESComputeJacobianAction(DM, Vec, Vec, Vec, void *);
1292 PETSC_EXTERN PetscErrorCode DMSNESCreateJacobianMF(DM, Vec, void *, Mat *);
1293 
1294 PETSC_EXTERN PetscErrorCode SNESNewtonALSetFunction(SNES, SNESFunctionFn *, void *ctx);
1295 PETSC_EXTERN PetscErrorCode SNESNewtonALGetFunction(SNES, SNESFunctionFn **, void **ctx);
1296 PETSC_EXTERN PetscErrorCode SNESNewtonALComputeFunction(SNES, Vec, Vec);
1297 PETSC_EXTERN PetscErrorCode SNESNewtonALGetLoadParameter(SNES, PetscReal *);
1298 
1299 /*MC
1300    SNESNewtonALCorrectionType - the approach used by `SNESNEWTONAL` to determine
1301    the correction to the current increment. While the exact correction satisfies
1302    the constraint surface at every iteration, it also requires solving a quadratic
1303    equation which may not have real roots. Conversely, the normal correction is more
1304    efficient and always yields a real correction and is the default.
1305 
1306    Values:
1307 +   `SNES_NEWTONAL_CORRECTION_EXACT` - choose the correction which exactly satisfies the constraint
1308 -   `SNES_NEWTONAL_CORRECTION_NORMAL` - choose the correction in the updated normal hyper-surface to the contraint surface
1309 
1310    Options Database Key:
1311 . -snes_newtonal_correction_type <exact> - select type from <exact,normal>
1312 
1313    Level: intermediate
1314 
1315 .seealso: `SNES`, `SNESNEWTONAL`, `SNESNewtonALSetCorrectionType()`
1316 M*/
1317 typedef enum {
1318   SNES_NEWTONAL_CORRECTION_EXACT  = 0,
1319   SNES_NEWTONAL_CORRECTION_NORMAL = 1,
1320 } SNESNewtonALCorrectionType;
1321 PETSC_EXTERN const char *const SNESNewtonALCorrectionTypes[];
1322 
1323 PETSC_EXTERN PetscErrorCode SNESNewtonALSetCorrectionType(SNES, SNESNewtonALCorrectionType);
1324