xref: /petsc/include/petscsnes.h (revision 4ad8454beace47809662cdae21ee081016eaa39a)
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 
11 /* SUBMANSEC = SNES */
12 
13 /*S
14    SNES - Abstract PETSc object that manages nonlinear solves
15 
16    Level: beginner
17 
18 .seealso: [](doc_nonlinsolve), [](ch_snes), `SNESCreate()`, `SNESSetType()`, `SNESType`, `TS`, `SNES`, `KSP`, `PC`, `SNESDestroy()`
19 S*/
20 typedef struct _p_SNES *SNES;
21 
22 /*J
23    SNESType - String with the name of a PETSc `SNES` method.
24 
25    Level: beginner
26 
27 .seealso: [](doc_nonlinsolve), [](ch_snes), `SNESSetType()`, `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFromOptions()`
28 J*/
29 typedef const char *SNESType;
30 #define SNESNEWTONLS         "newtonls"
31 #define SNESNEWTONTR         "newtontr"
32 #define SNESNEWTONTRDC       "newtontrdc"
33 #define SNESPYTHON           "python"
34 #define SNESNRICHARDSON      "nrichardson"
35 #define SNESKSPONLY          "ksponly"
36 #define SNESKSPTRANSPOSEONLY "ksptransposeonly"
37 #define SNESVINEWTONRSLS     "vinewtonrsls"
38 #define SNESVINEWTONSSLS     "vinewtonssls"
39 #define SNESNGMRES           "ngmres"
40 #define SNESQN               "qn"
41 #define SNESSHELL            "shell"
42 #define SNESNGS              "ngs"
43 #define SNESNCG              "ncg"
44 #define SNESFAS              "fas"
45 #define SNESMS               "ms"
46 #define SNESNASM             "nasm"
47 #define SNESANDERSON         "anderson"
48 #define SNESASPIN            "aspin"
49 #define SNESCOMPOSITE        "composite"
50 #define SNESPATCH            "patch"
51 
52 /* Logging support */
53 PETSC_EXTERN PetscClassId SNES_CLASSID;
54 PETSC_EXTERN PetscClassId DMSNES_CLASSID;
55 
56 PETSC_EXTERN PetscErrorCode SNESInitializePackage(void);
57 PETSC_EXTERN PetscErrorCode SNESFinalizePackage(void);
58 
59 PETSC_EXTERN PetscErrorCode SNESCreate(MPI_Comm, SNES *);
60 PETSC_EXTERN PetscErrorCode SNESReset(SNES);
61 PETSC_EXTERN PetscErrorCode SNESDestroy(SNES *);
62 PETSC_EXTERN PetscErrorCode SNESSetType(SNES, SNESType);
63 PETSC_EXTERN PetscErrorCode SNESMonitor(SNES, PetscInt, PetscReal);
64 PETSC_EXTERN PetscErrorCode SNESMonitorSet(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *), void *, PetscErrorCode (*)(void **));
65 PETSC_EXTERN PetscErrorCode SNESMonitorSetFromOptions(SNES, const char[], const char[], const char[], PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscViewerAndFormat *), PetscErrorCode (*)(SNES, PetscViewerAndFormat *));
66 PETSC_EXTERN PetscErrorCode SNESMonitorCancel(SNES);
67 PETSC_EXTERN PetscErrorCode SNESMonitorSAWs(SNES, PetscInt, PetscReal, void *);
68 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsCreate(SNES, void **);
69 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsDestroy(void **);
70 PETSC_EXTERN PetscErrorCode SNESSetConvergenceHistory(SNES, PetscReal[], PetscInt[], PetscInt, PetscBool);
71 PETSC_EXTERN PetscErrorCode SNESGetConvergenceHistory(SNES, PetscReal *[], PetscInt *[], PetscInt *);
72 PETSC_EXTERN PetscErrorCode SNESSetUp(SNES);
73 PETSC_EXTERN PetscErrorCode SNESSolve(SNES, Vec, Vec);
74 PETSC_EXTERN PetscErrorCode SNESSetErrorIfNotConverged(SNES, PetscBool);
75 PETSC_EXTERN PetscErrorCode SNESGetErrorIfNotConverged(SNES, PetscBool *);
76 PETSC_EXTERN PetscErrorCode SNESConverged(SNES, PetscInt, PetscReal, PetscReal, PetscReal);
77 
78 PETSC_EXTERN PetscErrorCode SNESSetWorkVecs(SNES, PetscInt);
79 
80 PETSC_EXTERN PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*)(SNES));
81 
82 PETSC_EXTERN PetscErrorCode SNESSetUpdate(SNES, PetscErrorCode (*)(SNES, PetscInt));
83 
84 PETSC_EXTERN PetscErrorCode SNESRegister(const char[], PetscErrorCode (*)(SNES));
85 
86 PETSC_EXTERN PetscErrorCode SNESGetKSP(SNES, KSP *);
87 PETSC_EXTERN PetscErrorCode SNESSetKSP(SNES, KSP);
88 PETSC_EXTERN PetscErrorCode SNESSetSolution(SNES, Vec);
89 PETSC_EXTERN PetscErrorCode SNESGetSolution(SNES, Vec *);
90 PETSC_EXTERN PetscErrorCode SNESGetSolutionUpdate(SNES, Vec *);
91 PETSC_EXTERN PetscErrorCode SNESGetRhs(SNES, Vec *);
92 PETSC_EXTERN PetscErrorCode SNESView(SNES, PetscViewer);
93 PETSC_EXTERN PetscErrorCode SNESLoad(SNES, PetscViewer);
94 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewSet(SNES, PetscErrorCode (*)(SNES, void *), void *, PetscErrorCode (*)(void **));
95 PETSC_EXTERN PetscErrorCode SNESViewFromOptions(SNES, PetscObject, const char[]);
96 PETSC_EXTERN PetscErrorCode SNESConvergedReasonView(SNES, PetscViewer);
97 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewFromOptions(SNES);
98 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewCancel(SNES);
99 
100 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonView()", ) static inline PetscErrorCode SNESReasonView(SNES snes, PetscViewer v)
101 {
102   return SNESConvergedReasonView(snes, v);
103 }
104 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonViewFromOptions()", ) static inline PetscErrorCode SNESReasonViewFromOptions(SNES snes)
105 {
106   return SNESConvergedReasonViewFromOptions(snes);
107 }
108 
109 #define SNES_FILE_CLASSID 1211224
110 
111 PETSC_EXTERN PetscErrorCode SNESSetOptionsPrefix(SNES, const char[]);
112 PETSC_EXTERN PetscErrorCode SNESAppendOptionsPrefix(SNES, const char[]);
113 PETSC_EXTERN PetscErrorCode SNESGetOptionsPrefix(SNES, const char *[]);
114 PETSC_EXTERN PetscErrorCode SNESSetFromOptions(SNES);
115 PETSC_EXTERN PetscErrorCode SNESResetFromOptions(SNES);
116 
117 PETSC_EXTERN PetscErrorCode SNESSetUseMatrixFree(SNES, PetscBool, PetscBool);
118 PETSC_EXTERN PetscErrorCode SNESGetUseMatrixFree(SNES, PetscBool *, PetscBool *);
119 PETSC_EXTERN PetscErrorCode MatCreateSNESMF(SNES, Mat *);
120 PETSC_EXTERN PetscErrorCode MatSNESMFGetSNES(Mat, SNES *);
121 PETSC_EXTERN PetscErrorCode MatSNESMFSetReuseBase(Mat, PetscBool);
122 PETSC_EXTERN PetscErrorCode MatSNESMFGetReuseBase(Mat, PetscBool *);
123 PETSC_EXTERN PetscErrorCode MatMFFDComputeJacobian(SNES, Vec, Mat, Mat, void *);
124 PETSC_EXTERN PetscErrorCode MatCreateSNESMFMore(SNES, Vec, Mat *);
125 PETSC_EXTERN PetscErrorCode MatSNESMFMoreSetParameters(Mat, PetscReal, PetscReal, PetscReal);
126 
127 PETSC_EXTERN PetscErrorCode SNESGetType(SNES, SNESType *);
128 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultSetUp(SNES, PetscViewerAndFormat *);
129 PETSC_EXTERN PetscErrorCode SNESMonitorDefault(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
130 PETSC_EXTERN PetscErrorCode SNESMonitorScaling(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
131 PETSC_EXTERN PetscErrorCode SNESMonitorRange(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
132 PETSC_EXTERN PetscErrorCode SNESMonitorRatio(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
133 PETSC_EXTERN PetscErrorCode SNESMonitorRatioSetUp(SNES, PetscViewerAndFormat *);
134 PETSC_EXTERN PetscErrorCode SNESMonitorSolution(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
135 PETSC_EXTERN PetscErrorCode SNESMonitorResidual(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
136 PETSC_EXTERN PetscErrorCode SNESMonitorSolutionUpdate(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
137 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultShort(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
138 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultField(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
139 PETSC_EXTERN PetscErrorCode SNESMonitorJacUpdateSpectrum(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
140 PETSC_EXTERN PetscErrorCode SNESMonitorFields(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
141 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidual(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
142 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLG(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
143 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLGCreate(PetscViewer, PetscViewerFormat, void *, PetscViewerAndFormat **);
144 
145 PETSC_EXTERN PetscErrorCode SNESSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt, PetscInt);
146 PETSC_EXTERN PetscErrorCode SNESSetDivergenceTolerance(SNES, PetscReal);
147 PETSC_EXTERN PetscErrorCode SNESGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *, PetscInt *);
148 PETSC_EXTERN PetscErrorCode SNESGetDivergenceTolerance(SNES, PetscReal *);
149 PETSC_EXTERN PetscErrorCode SNESSetTrustRegionTolerance(SNES, PetscReal);
150 PETSC_EXTERN PetscErrorCode SNESGetForceIteration(SNES, PetscBool *);
151 PETSC_EXTERN PetscErrorCode SNESSetForceIteration(SNES, PetscBool);
152 PETSC_EXTERN PetscErrorCode SNESGetIterationNumber(SNES, PetscInt *);
153 PETSC_EXTERN PetscErrorCode SNESSetIterationNumber(SNES, PetscInt);
154 
155 /*E
156    SNESNewtonTRFallbackType - type of fallback in case the solution of the trust-region subproblem is outside of the radius
157 
158    Values:
159 +  `SNES_TR_FALLBACK_NEWTON` - use scaled Newton step
160 .  `SNES_TR_FALLBACK_CAUCHY` - use Cauchy direction
161 -  `SNES_TR_FALLBACK_DOGLEG` - use dogleg method
162 
163    Level: intermediate
164 
165 .seealso: [](ch_snes), `SNES`, `SNESNEWTONTR`, `SNESNEWTONTRDC`
166 E*/
167 typedef enum {
168   SNES_TR_FALLBACK_NEWTON,
169   SNES_TR_FALLBACK_CAUCHY,
170   SNES_TR_FALLBACK_DOGLEG,
171 } SNESNewtonTRFallbackType;
172 
173 PETSC_EXTERN const char *const SNESNewtonTRFallbackTypes[];
174 
175 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetPreCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, PetscBool *, void *), void *ctx);
176 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetPreCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, PetscBool *, void *), void **ctx);
177 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetPostCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
178 PETSC_EXTERN PetscErrorCode SNESNewtonTRGetPostCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
179 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetFallbackType(SNES, SNESNewtonTRFallbackType);
180 PETSC_EXTERN PetscErrorCode SNESNewtonTRPreCheck(SNES, Vec, Vec, PetscBool *);
181 PETSC_EXTERN PetscErrorCode SNESNewtonTRPostCheck(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *);
182 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetNormType(SNES, NormType);
183 
184 /*E
185     SNESNewtonTRQNType - type of quasi-Newton model to use
186 
187    Values:
188 +  `SNES_TR_QN_NONE` - do not use a quasi-Newton model
189 .  `SNES_TR_QN_SAME` - use the same quasi-Newton model for matrix and preconditioner
190 -  `SNES_TR_QN_DIFFERENT` - use different quasi-Newton models for matrix and preconditioner
191 
192    Level: intermediate
193 
194 .seealso: [](ch_snes), `SNES`, `SNESNEWTONTR`
195 E*/
196 typedef enum {
197   SNES_TR_QN_NONE,
198   SNES_TR_QN_SAME,
199   SNES_TR_QN_DIFFERENT,
200 } SNESNewtonTRQNType;
201 
202 PETSC_EXTERN const char *const SNESNewtonTRQNTypes[];
203 
204 PETSC_EXTERN PetscErrorCode SNESNewtonTRSetQNType(SNES, SNESNewtonTRQNType);
205 
206 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetRhoFlag(SNES, PetscBool *);
207 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPreCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, PetscBool *, void *), void *ctx);
208 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPreCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, PetscBool *, void *), void **ctx);
209 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPostCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
210 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPostCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
211 
212 PETSC_EXTERN PetscErrorCode SNESGetNonlinearStepFailures(SNES, PetscInt *);
213 PETSC_EXTERN PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES, PetscInt);
214 PETSC_EXTERN PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES, PetscInt *);
215 PETSC_EXTERN PetscErrorCode SNESGetNumberFunctionEvals(SNES, PetscInt *);
216 
217 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditioner(SNES, PetscInt);
218 PETSC_EXTERN PetscErrorCode SNESGetLagPreconditioner(SNES, PetscInt *);
219 PETSC_EXTERN PetscErrorCode SNESSetLagJacobian(SNES, PetscInt);
220 PETSC_EXTERN PetscErrorCode SNESGetLagJacobian(SNES, PetscInt *);
221 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditionerPersists(SNES, PetscBool);
222 PETSC_EXTERN PetscErrorCode SNESSetLagJacobianPersists(SNES, PetscBool);
223 PETSC_EXTERN PetscErrorCode SNESSetGridSequence(SNES, PetscInt);
224 PETSC_EXTERN PetscErrorCode SNESGetGridSequence(SNES, PetscInt *);
225 
226 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveIterations(SNES, PetscInt *);
227 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveFailures(SNES, PetscInt *);
228 PETSC_EXTERN PetscErrorCode SNESSetMaxLinearSolveFailures(SNES, PetscInt);
229 PETSC_EXTERN PetscErrorCode SNESGetMaxLinearSolveFailures(SNES, PetscInt *);
230 PETSC_EXTERN PetscErrorCode SNESSetCountersReset(SNES, PetscBool);
231 
232 PETSC_EXTERN PetscErrorCode SNESKSPSetUseEW(SNES, PetscBool);
233 PETSC_EXTERN PetscErrorCode SNESKSPGetUseEW(SNES, PetscBool *);
234 PETSC_EXTERN PetscErrorCode SNESKSPSetParametersEW(SNES, PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal);
235 PETSC_EXTERN PetscErrorCode SNESKSPGetParametersEW(SNES, PetscInt *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *);
236 
237 #include <petscdrawtypes.h>
238 PETSC_EXTERN PetscErrorCode SNESMonitorLGRange(SNES, PetscInt, PetscReal, void *);
239 
240 PETSC_EXTERN PetscErrorCode SNESSetApplicationContext(SNES, void *);
241 PETSC_EXTERN PetscErrorCode SNESGetApplicationContext(SNES, void *);
242 PETSC_EXTERN PetscErrorCode SNESSetComputeApplicationContext(SNES, PetscErrorCode (*)(SNES, void **), PetscErrorCode (*)(void **));
243 
244 PETSC_EXTERN PetscErrorCode SNESPythonSetType(SNES, const char[]);
245 PETSC_EXTERN PetscErrorCode SNESPythonGetType(SNES, const char *[]);
246 
247 PETSC_EXTERN PetscErrorCode SNESSetFunctionDomainError(SNES);
248 PETSC_EXTERN PetscErrorCode SNESGetFunctionDomainError(SNES, PetscBool *);
249 PETSC_EXTERN PetscErrorCode SNESGetJacobianDomainError(SNES, PetscBool *);
250 PETSC_EXTERN PetscErrorCode SNESSetJacobianDomainError(SNES);
251 PETSC_EXTERN PetscErrorCode SNESSetCheckJacobianDomainError(SNES, PetscBool);
252 PETSC_EXTERN PetscErrorCode SNESGetCheckJacobianDomainError(SNES, PetscBool *);
253 
254 #define SNES_CONVERGED_TR_DELTA_DEPRECATED SNES_CONVERGED_TR_DELTA PETSC_DEPRECATED_ENUM(3, 12, 0, "SNES_DIVERGED_TR_DELTA", )
255 /*E
256     SNESConvergedReason - reason a `SNESSolve()` was determined to have converged or diverged
257 
258    Values:
259 +  `SNES_CONVERGED_FNORM_ABS`      - 2-norm(F) <= abstol
260 .  `SNES_CONVERGED_FNORM_RELATIVE` - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
261 .  `SNES_CONVERGED_SNORM_RELATIVE` - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
262 .  `SNES_DIVERGED_FUNCTION_COUNT`  - The user provided function has been called more times than the maximum set in `SNESSetTolerances()`
263 .  `SNES_DIVERGED_DTOL`            - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
264 .  `SNES_DIVERGED_FNORM_NAN`       - the 2-norm of the current function evaluation is not-a-number (NaN), this
265                                      is usually caused by a division of 0 by 0.
266 .  `SNES_DIVERGED_MAX_IT`          - `SNESSolve()` has reached the maximum number of iterations requested
267 .  `SNES_DIVERGED_LINE_SEARCH`     - The line search has failed. This only occurs for `SNES` solvers that use a line search
268 .  `SNES_DIVERGED_LOCAL_MIN`       - the algorithm seems to have stagnated at a local minimum that is not zero.
269 -  `SNES_CONERGED_ITERATING`       - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
270 
271    Level: beginner
272 
273     Notes:
274    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
275    testing with `-pc_type lu` to eliminate the linear solver as the cause of the problem).
276 
277    `SNES_DIVERGED_LOCAL_MIN` can only occur when using the line-search variant of `SNES`.
278    The line search wants to minimize Q(alpha) = 1/2 || F(x + alpha s) ||^2_2  this occurs
279    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
280    you get Q'(alpha) = -F(x)^T F'(x)^(-1)^T F'(x+alpha s)F(x+alpha s); when alpha = 0
281    Q'(0) = - ||F(x)||^2_2 which is always NEGATIVE if F'(x) is invertible. This means the Newton
282    direction is a descent direction and the line search should succeed if alpha is small enough.
283 
284    If F'(x) is NOT invertible AND F'(x)^T F(x) = 0 then Q'(0) = 0 and the Newton direction
285    is NOT a descent direction so the line search will fail. All one can do at this point
286    is change the initial guess and try again.
287 
288    An alternative explanation: Newton's method can be regarded as replacing the function with
289    its linear approximation and minimizing the 2-norm of that. That is F(x+s) approx F(x) + F'(x)s
290    so we minimize || F(x) + F'(x) s ||^2_2; do this using Least Squares. If F'(x) is invertible then
291    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
292    exists a nontrivial (that is F'(x)s != 0) solution to the equation and this direction is
293    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)
294    = - (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
295    and F'(x)^T F'(x) has no negative eigenvalues Q'(0) < 0 so s is a descent direction and the line
296    search should succeed for small enough alpha.
297 
298    Note that this RARELY happens in practice. Far more likely the linear system is not being solved
299    (well enough?) or the Jacobian is wrong.
300 
301    `SNES_DIVERGED_MAX_IT` means that the solver reached the maximum number of iterations without satisfying any
302    convergence criteria. `SNES_CONVERGED_ITS` means that `SNESConvergedSkip()` was chosen as the convergence test;
303    thus the usual convergence criteria have not been checked and may or may not be satisfied.
304 
305 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`, `SNESSetTolerances()`
306 E*/
307 typedef enum {                       /* converged */
308   SNES_CONVERGED_FNORM_ABS      = 2, /* ||F|| < atol */
309   SNES_CONVERGED_FNORM_RELATIVE = 3, /* ||F|| < rtol*||F_initial|| */
310   SNES_CONVERGED_SNORM_RELATIVE = 4, /* Newton computed step size small; || delta x || < stol || x ||*/
311   SNES_CONVERGED_ITS            = 5, /* maximum iterations reached */
312   SNES_BREAKOUT_INNER_ITER      = 6, /* Flag to break out of inner loop after checking custom convergence. */
313                                      /* it is used in multi-phase flow when state changes */
314   /* diverged */
315   SNES_DIVERGED_FUNCTION_DOMAIN      = -1, /* the new x location passed the function is not in the domain of F */
316   SNES_DIVERGED_FUNCTION_COUNT       = -2,
317   SNES_DIVERGED_LINEAR_SOLVE         = -3, /* the linear solve failed */
318   SNES_DIVERGED_FNORM_NAN            = -4,
319   SNES_DIVERGED_MAX_IT               = -5,
320   SNES_DIVERGED_LINE_SEARCH          = -6,  /* the line search failed */
321   SNES_DIVERGED_INNER                = -7,  /* inner solve failed */
322   SNES_DIVERGED_LOCAL_MIN            = -8,  /* || J^T b || is small, implies converged to local minimum of F() */
323   SNES_DIVERGED_DTOL                 = -9,  /* || F || > divtol*||F_initial|| */
324   SNES_DIVERGED_JACOBIAN_DOMAIN      = -10, /* Jacobian calculation does not make sense */
325   SNES_DIVERGED_TR_DELTA             = -11,
326   SNES_CONVERGED_TR_DELTA_DEPRECATED = -11,
327 
328   SNES_CONVERGED_ITERATING = 0
329 } SNESConvergedReason;
330 PETSC_EXTERN const char *const *SNESConvergedReasons;
331 
332 /*MC
333    SNES_CONVERGED_FNORM_ABS - 2-norm(F) <= abstol
334 
335    Level: beginner
336 
337 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
338 M*/
339 
340 /*MC
341    SNES_CONVERGED_FNORM_RELATIVE - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
342 
343    Level: beginner
344 
345 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
346 M*/
347 
348 /*MC
349   SNES_CONVERGED_SNORM_RELATIVE - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
350   solution and stol is the 4th argument to `SNESSetTolerances()`
351 
352   Options Database Key:
353   -snes_stol <stol> - the step tolerance
354 
355    Level: beginner
356 
357 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
358 M*/
359 
360 /*MC
361    SNES_DIVERGED_FUNCTION_COUNT - The user provided function has been called more times then the final
362    argument to `SNESSetTolerances()`
363 
364    Level: beginner
365 
366 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
367 M*/
368 
369 /*MC
370    SNES_DIVERGED_DTOL - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
371 
372    Level: beginner
373 
374 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESSetDivergenceTolerance()`
375 M*/
376 
377 /*MC
378    SNES_DIVERGED_FNORM_NAN - the 2-norm of the current function evaluation is not-a-number (NaN), this
379    is usually caused by a division of 0 by 0.
380 
381    Level: beginner
382 
383 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
384 M*/
385 
386 /*MC
387    SNES_DIVERGED_MAX_IT - SNESSolve() has reached the maximum number of iterations requested
388 
389    Level: beginner
390 
391 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
392 M*/
393 
394 /*MC
395    SNES_DIVERGED_LINE_SEARCH - The line search has failed. This only occurs for a `SNES` solvers that use a line search
396 
397    Level: beginner
398 
399 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESLineSearch`
400 M*/
401 
402 /*MC
403    SNES_DIVERGED_LOCAL_MIN - the algorithm seems to have stagnated at a local minimum that is not zero.
404    See the manual page for `SNESConvergedReason` for more details
405 
406    Level: beginner
407 
408 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
409 M*/
410 
411 /*MC
412    SNES_CONERGED_ITERATING - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
413 
414    Level: beginner
415 
416 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
417 M*/
418 
419 PETSC_EXTERN PetscErrorCode SNESSetConvergenceTest(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *, PetscErrorCode (*)(void *));
420 PETSC_EXTERN PetscErrorCode SNESConvergedDefault(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
421 PETSC_EXTERN PetscErrorCode SNESConvergedSkip(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
422 PETSC_EXTERN PetscErrorCode SNESConvergedCorrectPressure(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
423 PETSC_EXTERN PetscErrorCode SNESGetConvergedReason(SNES, SNESConvergedReason *);
424 PETSC_EXTERN PetscErrorCode SNESGetConvergedReasonString(SNES, const char **);
425 PETSC_EXTERN PetscErrorCode SNESSetConvergedReason(SNES, SNESConvergedReason);
426 
427 PETSC_DEPRECATED_FUNCTION(3, 5, 0, "SNESConvergedSkip()", ) static inline void SNESSkipConverged(void)
428 { /* never called */
429 }
430 #define SNESSkipConverged (SNESSkipConverged, SNESConvergedSkip)
431 
432 /*S
433   SNESInitialGuessFn - A prototype of a `SNES` compute initial guess function that would be passed to `SNESSetComputeInitialGuess()`
434 
435   Calling Sequence:
436 + snes  - `SNES` context
437 . u   - output vector to contain initial guess
438 - ctx - [optional] user-defined function context
439 
440   Level: beginner
441 
442 .seealso: [](ch_snes), `SNES`, `SNESSetComputeInitialGuess()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESFunctionFn`
443 S*/
444 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESInitialGuessFn)(SNES snes, Vec u, void *ctx);
445 
446 /*S
447   SNESFunctionFn - A prototype of a `SNES` evaluation function that would be passed to `SNESSetFunction()`
448 
449   Calling Sequence:
450 + snes  - `SNES` context
451 . u   - input vector
452 . F   - function vector
453 - ctx - [optional] user-defined function context
454 
455   Level: beginner
456 
457 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
458 S*/
459 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESFunctionFn)(SNES snes, Vec u, Vec F, void *ctx);
460 
461 /*S
462   SNESObjectiveFn - A prototype of a `SNES` objective evaluation function that would be passed to `SNESSetObjective()`
463 
464   Calling Sequence:
465 + snes  - `SNES` context
466 . u   - input vector
467 . o   - output value
468 - ctx - [optional] user-defined function context
469 
470   Level: beginner
471 
472 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
473 S*/
474 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESObjectiveFn)(SNES snes, Vec u, PetscReal *o, void *ctx);
475 
476 /*S
477   SNESJacobianFn - A prototype of a `SNES` Jacobian evaluation function that would be passed to `SNESSetJacobian()`
478 
479   Calling Sequence:
480 + snes   - the `SNES` context obtained from `SNESCreate()`
481 . u    - input vector
482 . Amat - (approximate) Jacobian matrix
483 . Pmat - matrix used to construct the preconditioner, often the same as `Amat`
484 - ctx  - [optional] user-defined context for matrix evaluation routine
485 
486   Level: beginner
487 
488 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESNGSFn`
489 S*/
490 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESJacobianFn)(SNES snes, Vec u, Mat Amat, Mat Pmat, void *ctx);
491 
492 /*S
493   SNESNGSFn - A prototype of a `SNES` nonlinear Gauss-Seidel function that would be passed to `SNESSetNGS()`
494 
495   Calling Sequence:
496 + snes   - the `SNES` context obtained from `SNESCreate()`
497 . u    - the current solution, updated in place
498 . b    - the right hand side vector (which may be `NULL`)
499 - ctx  - [optional] user-defined context for matrix evaluation routine
500 
501   Level: beginner
502 
503 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`
504 S*/
505 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESNGSFn)(SNES snes, Vec u, Vec b, void *ctx);
506 
507 /* --------- Solving systems of nonlinear equations --------------- */
508 PETSC_EXTERN PetscErrorCode SNESSetFunction(SNES, Vec, SNESFunctionFn *, void *);
509 PETSC_EXTERN PetscErrorCode SNESGetFunction(SNES, Vec *, SNESFunctionFn **, void **);
510 PETSC_EXTERN PetscErrorCode SNESComputeFunction(SNES, Vec, Vec);
511 PETSC_EXTERN PetscErrorCode SNESComputeMFFunction(SNES, Vec, Vec);
512 PETSC_EXTERN PetscErrorCode SNESSetInitialFunction(SNES, Vec);
513 
514 PETSC_EXTERN PetscErrorCode SNESSetJacobian(SNES, Mat, Mat, SNESJacobianFn *, void *);
515 PETSC_EXTERN PetscErrorCode SNESGetJacobian(SNES, Mat *, Mat *, SNESJacobianFn **, void **);
516 PETSC_EXTERN SNESFunctionFn SNESObjectiveComputeFunctionDefaultFD;
517 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefault;
518 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefaultColor;
519 PETSC_EXTERN PetscErrorCode SNESPruneJacobianColor(SNES, Mat, Mat);
520 PETSC_EXTERN PetscErrorCode SNESSetComputeInitialGuess(SNES, SNESInitialGuessFn *, void *);
521 PETSC_EXTERN PetscErrorCode SNESSetPicard(SNES, Vec, SNESFunctionFn *, Mat, Mat, SNESJacobianFn *, void *);
522 PETSC_EXTERN PetscErrorCode SNESGetPicard(SNES, Vec *, SNESFunctionFn **, Mat *, Mat *, SNESJacobianFn **, void **);
523 PETSC_EXTERN SNESFunctionFn SNESPicardComputeFunction;
524 PETSC_EXTERN SNESFunctionFn SNESPicardComputeMFFunction;
525 PETSC_EXTERN SNESJacobianFn SNESPicardComputeJacobian;
526 
527 PETSC_EXTERN PetscErrorCode SNESSetObjective(SNES, SNESObjectiveFn *, void *);
528 PETSC_EXTERN PetscErrorCode SNESGetObjective(SNES, SNESObjectiveFn **, void **);
529 PETSC_EXTERN PetscErrorCode SNESComputeObjective(SNES, Vec, PetscReal *);
530 
531 /*E
532    SNESNormSchedule - Frequency with which the norm is computed during a nonliner solve
533 
534    Values:
535 +   `SNES_NORM_DEFAULT`            - use the default behavior for the current `SNESType`
536 .   `SNES_NORM_NONE`               - avoid all norm computations
537 .   `SNES_NORM_ALWAYS`             - compute the norms whenever possible
538 .   `SNES_NORM_INITIAL_ONLY`       - compute the norm only when the algorithm starts
539 .   `SNES_NORM_FINAL_ONLY`         - compute the norm only when the algorithm finishes
540 -   `SNES_NORM_INITIAL_FINAL_ONLY` - compute the norm at the start and end of the algorithm
541 
542    Level: advanced
543 
544    Notes:
545    Support for these is highly dependent on the solver.
546 
547    Some options limit the convergence tests that can be used.
548 
549    The `SNES_NORM_NONE` option is most commonly used when the nonlinear solver is being used as a smoother, for example for `SNESFAS`
550 
551    This is primarily used to turn off extra norm and function computation
552    when the solvers are composed.
553 
554 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
555           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
556 E*/
557 typedef enum {
558   SNES_NORM_DEFAULT            = -1,
559   SNES_NORM_NONE               = 0,
560   SNES_NORM_ALWAYS             = 1,
561   SNES_NORM_INITIAL_ONLY       = 2,
562   SNES_NORM_FINAL_ONLY         = 3,
563   SNES_NORM_INITIAL_FINAL_ONLY = 4
564 } SNESNormSchedule;
565 PETSC_EXTERN const char *const *const SNESNormSchedules;
566 
567 /*MC
568    SNES_NORM_NONE - Don't compute function and its L2 norm when possible
569 
570    Level: advanced
571 
572    Note:
573    This is most useful for stationary solvers with a fixed number of iterations used as smoothers.
574 
575 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_DEFAULT`
576 M*/
577 
578 /*MC
579    SNES_NORM_ALWAYS - Compute the function and its L2 norm at each iteration.
580 
581    Level: advanced
582 
583    Note:
584    Most solvers will use this no matter what norm type is passed to them.
585 
586 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_NONE`
587 M*/
588 
589 /*MC
590    SNES_NORM_INITIAL_ONLY - Compute the function and its L2 at iteration 0, but do not update it.
591 
592    Level: advanced
593 
594    Notes:
595    This method is useful in composed methods, when a true solution might actually be found before `SNESSolve()` is called.
596    This option enables the solve to abort on the zeroth iteration if this is the case.
597 
598    For solvers that require the computation of the L2 norm of the function as part of the method, this merely cancels
599    the norm computation at the last iteration (if possible).
600 
601 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_FINAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
602 M*/
603 
604 /*MC
605    SNES_NORM_FINAL_ONLY - Compute the function and its L2 norm on only the final iteration.
606 
607    Level: advanced
608 
609    Note:
610    For solvers that require the computation of the L2 norm of the function as part of the method, behaves
611    exactly as `SNES_NORM_DEFAULT`.  This method is useful when the function is gotten after `SNESSolve()` and
612    used in subsequent computation for methods that do not need the norm computed during the rest of the
613    solution procedure.
614 
615 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_INITIAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
616 M*/
617 
618 /*MC
619    SNES_NORM_INITIAL_FINAL_ONLY - Compute the function and its L2 norm on only the initial and final iterations.
620 
621    Level: advanced
622 
623    Note:
624    This method combines the benefits of `SNES_NORM_INITIAL_ONLY` and `SNES_NORM_FINAL_ONLY`.
625 
626 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_SNES_NORM_INITIAL_ONLY`, `SNES_NORM_FINAL_ONLY`
627 M*/
628 
629 PETSC_EXTERN PetscErrorCode SNESSetNormSchedule(SNES, SNESNormSchedule);
630 PETSC_EXTERN PetscErrorCode SNESGetNormSchedule(SNES, SNESNormSchedule *);
631 PETSC_EXTERN PetscErrorCode SNESSetFunctionNorm(SNES, PetscReal);
632 PETSC_EXTERN PetscErrorCode SNESGetFunctionNorm(SNES, PetscReal *);
633 PETSC_EXTERN PetscErrorCode SNESGetUpdateNorm(SNES, PetscReal *);
634 PETSC_EXTERN PetscErrorCode SNESGetSolutionNorm(SNES, PetscReal *);
635 
636 /*E
637    SNESFunctionType - Type of function computed
638 
639    Values:
640 +  `SNES_FUNCTION_DEFAULT`          - the default behavior for the current `SNESType`
641 .  `SNES_FUNCTION_UNPRECONDITIONED` - the original function provided
642 -  `SNES_FUNCTION_PRECONDITIONED`   - the modification of the function by the preconditioner
643 
644    Level: advanced
645 
646    Note:
647    Support for these is dependent on the solver.
648 
649 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
650           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
651 E*/
652 typedef enum {
653   SNES_FUNCTION_DEFAULT          = -1,
654   SNES_FUNCTION_UNPRECONDITIONED = 0,
655   SNES_FUNCTION_PRECONDITIONED   = 1
656 } SNESFunctionType;
657 PETSC_EXTERN const char *const *const SNESFunctionTypes;
658 
659 PETSC_EXTERN PetscErrorCode SNESSetFunctionType(SNES, SNESFunctionType);
660 PETSC_EXTERN PetscErrorCode SNESGetFunctionType(SNES, SNESFunctionType *);
661 
662 PETSC_EXTERN PetscErrorCode SNESSetNGS(SNES, SNESNGSFn *, void *);
663 PETSC_EXTERN PetscErrorCode SNESGetNGS(SNES, SNESNGSFn **, void **);
664 PETSC_EXTERN PetscErrorCode SNESComputeNGS(SNES, Vec, Vec);
665 
666 PETSC_EXTERN PetscErrorCode SNESNGSSetSweeps(SNES, PetscInt);
667 PETSC_EXTERN PetscErrorCode SNESNGSGetSweeps(SNES, PetscInt *);
668 PETSC_EXTERN PetscErrorCode SNESNGSSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt);
669 PETSC_EXTERN PetscErrorCode SNESNGSGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
670 
671 PETSC_EXTERN PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES, PetscBool);
672 PETSC_EXTERN PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES, PetscBool *);
673 
674 PETSC_EXTERN PetscErrorCode SNESShellGetContext(SNES, void *);
675 PETSC_EXTERN PetscErrorCode SNESShellSetContext(SNES, void *);
676 PETSC_EXTERN PetscErrorCode SNESShellSetSolve(SNES, PetscErrorCode (*)(SNES, Vec));
677 
678 /* --------- Routines specifically for line search methods --------------- */
679 
680 /*S
681    SNESLineSearch - Abstract PETSc object that manages line-search operations for nonlinear solvers
682 
683    Level: beginner
684 
685 .seealso: [](ch_snes), `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetType()`, `SNES`
686 S*/
687 typedef struct _p_LineSearch *SNESLineSearch;
688 
689 /*J
690    SNESLineSearchType - String with the name of a PETSc line search method `SNESLineSearch`
691 
692    Values:
693 +  `SNESLINESEARCHBASIC`   - (or equivalently `SNESLINESEARCHNONE`) Simple damping line search, defaults to using the full Newton step
694 .  `SNESLINESEARCHBT`      - Backtracking line search over the L2 norm of the function
695 .  `SNESLINESEARCHL2`      - Secant line search over the L2 norm of the function
696 .  `SNESLINESEARCHCP`      - Critical point secant line search assuming F(x) = grad G(x) for some unknown G(x)
697 .  `SNESLINESEARCHNLEQERR` - Affine-covariant error-oriented linesearch
698 -  `SNESLINESEARCHSHELL`   - User provided `SNESLineSearch` implementation
699 
700    Level: beginner
701 
702 .seealso: [](ch_snes), `SNESLineSearch`, `SNESLineSearchSetType()`, `SNES`
703 J*/
704 typedef const char *SNESLineSearchType;
705 #define SNESLINESEARCHBT        "bt"
706 #define SNESLINESEARCHNLEQERR   "nleqerr"
707 #define SNESLINESEARCHBASIC     "basic"
708 #define SNESLINESEARCHNONE      "none"
709 #define SNESLINESEARCHL2        "l2"
710 #define SNESLINESEARCHCP        "cp"
711 #define SNESLINESEARCHSHELL     "shell"
712 #define SNESLINESEARCHNCGLINEAR "ncglinear"
713 
714 PETSC_EXTERN PetscFunctionList SNESList;
715 PETSC_EXTERN PetscClassId      SNESLINESEARCH_CLASSID;
716 PETSC_EXTERN PetscFunctionList SNESLineSearchList;
717 
718 #define SNES_LINESEARCH_ORDER_LINEAR    1
719 #define SNES_LINESEARCH_ORDER_QUADRATIC 2
720 #define SNES_LINESEARCH_ORDER_CUBIC     3
721 
722 /*S
723   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that projects a vector onto the VI bounds, passed to `SNESLineSearchSetVIFunctions()`
724 
725   Calling Sequence:
726 + snes  - `SNES` context
727 - u     - the vector to project to the bounds
728 
729   Level: advanced
730 
731   Note:
732   The deprecated `SNESLineSearchVIProjectFunc` still works as a replacement for `SNESLineSearchVIProjectFn` *.
733 
734 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
735 S*/
736 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVIProjectFn)(SNES snes, Vec u);
737 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVIProjectFn *SNESLineSearchVIProjectFunc; // deprecated
738 
739 /*S
740   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that computes the norm of the active set variables in a vector in a VI solve,
741   passed to `SNESLineSearchSetVIFunctions()`
742 
743   Calling Sequence:
744 + snes  - `SNES` context
745 . f     - the vector to compute the norm of
746 . u     - the current solution, entries that are on the VI bounds are ignored
747 - fnorm - the resulting norm
748 
749   Level: advanced
750 
751   Note:
752   The deprecated `SNESLineSearchVINormFunc` still works as a replacement for `SNESLineSearchVINormFn` *.
753 
754 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
755 S*/
756 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVINormFn)(SNES snes, Vec f, Vec u, PetscReal *fnorm);
757 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVINormFn *SNESLineSearchVINormFunc; // deprecated
758 
759 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchApplyFn)(SNESLineSearch);
760 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchApplyFn *SNESLineSearchApplyFunc; // deprecated
761 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchShellApplyFn)(SNESLineSearch, void *);
762 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchShellApplyFn *SNESLineSearchUserFunc; // deprecated
763 
764 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate(MPI_Comm, SNESLineSearch *);
765 PETSC_EXTERN PetscErrorCode SNESLineSearchReset(SNESLineSearch);
766 PETSC_EXTERN PetscErrorCode SNESLineSearchView(SNESLineSearch, PetscViewer);
767 PETSC_EXTERN PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *);
768 PETSC_EXTERN PetscErrorCode SNESLineSearchGetType(SNESLineSearch, SNESLineSearchType *);
769 PETSC_EXTERN PetscErrorCode SNESLineSearchSetType(SNESLineSearch, SNESLineSearchType);
770 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch);
771 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch, PetscErrorCode (*)(SNES, Vec, Vec));
772 PETSC_EXTERN PetscErrorCode SNESLineSearchSetUp(SNESLineSearch);
773 PETSC_EXTERN PetscErrorCode SNESLineSearchApply(SNESLineSearch, Vec, Vec, PetscReal *, Vec);
774 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch, Vec, Vec, PetscBool *);
775 PETSC_EXTERN PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *);
776 PETSC_EXTERN PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch, PetscInt);
777 
778 /* set the functions for precheck and postcheck */
779 
780 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void *ctx);
781 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
782 
783 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void **ctx);
784 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
785 
786 /* set the functions for VI-specific line search operations */
787 
788 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn *, SNESLineSearchVINormFn *);
789 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn **, SNESLineSearchVINormFn **);
790 
791 /* pointers to the associated SNES in order to be able to get the function evaluation out */
792 PETSC_EXTERN PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch, SNES);
793 PETSC_EXTERN PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch, SNES *);
794 
795 /* set and get the parameters and vectors */
796 PETSC_EXTERN PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
797 PETSC_EXTERN PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscInt);
798 
799 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch, Vec, Vec, PetscBool *, void *);
800 
801 PETSC_EXTERN PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch, PetscReal *);
802 PETSC_EXTERN PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch, PetscReal);
803 
804 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch, PetscReal *);
805 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch, PetscReal);
806 
807 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch, PetscInt *order);
808 PETSC_EXTERN PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch, PetscInt order);
809 
810 /*E
811     SNESLineSearchReason - indication if the line search has succeeded or failed and why
812 
813   Values:
814 +  `SNES_LINESEARCH_SUCCEEDED`       - the line search succeeded
815 .  `SNES_LINESEARCH_FAILED_NANORINF` - a not a number of infinity appeared in the computions
816 .  `SNES_LINESEARCH_FAILED_DOMAIN`   - the function was evaluated outside of its domain, see `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
817 .  `SNES_LINESEARCH_FAILED_REDUCT`   - the linear search failed to get the requested decrease in its norm or objective
818 .  `SNES_LINESEARCH_FAILED_USER`     - used by `SNESLINESEARCHNLEQERR` to indicate the user changed the search direction inappropriately
819 -  `SNES_LINESEARCH_FAILED_FUNCTION` - indicates the maximum number of function evaluations allowed has been surpassed, `SNESConvergedReason` is also
820                                        set to `SNES_DIVERGED_FUNCTION_COUNT`
821 
822    Level: intermediate
823 
824    Developer Note:
825    Some of these reasons overlap with values of `SNESConvergedReason`
826 
827 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`,
828           `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
829 E*/
830 typedef enum {
831   SNES_LINESEARCH_SUCCEEDED,
832   SNES_LINESEARCH_FAILED_NANORINF,
833   SNES_LINESEARCH_FAILED_DOMAIN,
834   SNES_LINESEARCH_FAILED_REDUCT, /* INSUFFICIENT REDUCTION */
835   SNES_LINESEARCH_FAILED_USER,
836   SNES_LINESEARCH_FAILED_FUNCTION
837 } SNESLineSearchReason;
838 
839 PETSC_EXTERN PetscErrorCode SNESLineSearchGetReason(SNESLineSearch, SNESLineSearchReason *);
840 PETSC_EXTERN PetscErrorCode SNESLineSearchSetReason(SNESLineSearch, SNESLineSearchReason);
841 
842 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch, Vec *, Vec *, Vec *, Vec *, Vec *);
843 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch, Vec, Vec, Vec, Vec, Vec);
844 
845 PETSC_EXTERN PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *);
846 PETSC_EXTERN PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch, PetscReal, PetscReal, PetscReal);
847 PETSC_EXTERN PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch);
848 PETSC_EXTERN PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch, PetscBool);
849 
850 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitor(SNESLineSearch);
851 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSet(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, void *), void *, PetscErrorCode (*)(void **));
852 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSetFromOptions(SNESLineSearch, const char[], const char[], const char[], PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *), PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *));
853 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorCancel(SNESLineSearch);
854 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch, PetscViewer);
855 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDefaultMonitor(SNESLineSearch, PetscViewer *);
856 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSolutionUpdate(SNESLineSearch, PetscViewerAndFormat *);
857 
858 PETSC_EXTERN PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch, const char prefix[]);
859 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch, const char *prefix[]);
860 
861 /* Shell interface functions */
862 PETSC_EXTERN PetscErrorCode SNESLineSearchShellSetApply(SNESLineSearch, SNESLineSearchShellApplyFn, void *);
863 PETSC_EXTERN PetscErrorCode SNESLineSearchShellGetApply(SNESLineSearch, SNESLineSearchShellApplyFn **, void **);
864 
865 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellSetApply()", ) static inline PetscErrorCode SNESLineSearchShellSetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc f, void *ctx)
866 {
867   return SNESLineSearchShellSetApply(ls, f, ctx);
868 }
869 
870 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellGetApply()", ) static inline PetscErrorCode SNESLineSearchShellGetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc *f, void **ctx)
871 {
872   return SNESLineSearchShellGetApply(ls, f, ctx);
873 }
874 
875 /* BT interface functions */
876 PETSC_EXTERN PetscErrorCode SNESLineSearchBTSetAlpha(SNESLineSearch, PetscReal);
877 PETSC_EXTERN PetscErrorCode SNESLineSearchBTGetAlpha(SNESLineSearch, PetscReal *);
878 
879 /*register line search types */
880 PETSC_EXTERN PetscErrorCode SNESLineSearchRegister(const char[], PetscErrorCode (*)(SNESLineSearch));
881 
882 /* Routines for VI solver */
883 PETSC_EXTERN PetscErrorCode SNESVISetVariableBounds(SNES, Vec, Vec);
884 PETSC_EXTERN PetscErrorCode SNESVIGetVariableBounds(SNES, Vec *, Vec *);
885 PETSC_EXTERN PetscErrorCode SNESVISetComputeVariableBounds(SNES, PetscErrorCode (*)(SNES, Vec, Vec));
886 PETSC_EXTERN PetscErrorCode SNESVIGetInactiveSet(SNES, IS *);
887 PETSC_EXTERN PetscErrorCode SNESVIGetActiveSetIS(SNES, Vec, Vec, IS *);
888 PETSC_EXTERN PetscErrorCode SNESVIComputeInactiveSetFnorm(SNES, Vec, Vec, PetscReal *);
889 PETSC_EXTERN PetscErrorCode SNESVISetRedundancyCheck(SNES, PetscErrorCode (*)(SNES, IS, IS *, void *), void *);
890 PETSC_EXTERN PetscErrorCode SNESVIComputeMeritFunction(Vec, PetscReal *, PetscReal *);
891 PETSC_EXTERN PetscErrorCode SNESVIComputeFunction(SNES, Vec, Vec, void *);
892 PETSC_EXTERN PetscErrorCode DMSetVI(DM, IS);
893 PETSC_EXTERN PetscErrorCode DMDestroyVI(DM);
894 
895 PETSC_EXTERN PetscErrorCode SNESTestLocalMin(SNES);
896 
897 /* Should this routine be private? */
898 PETSC_EXTERN PetscErrorCode SNESComputeJacobian(SNES, Vec, Mat, Mat);
899 PETSC_EXTERN PetscErrorCode SNESTestJacobian(SNES);
900 PETSC_EXTERN PetscErrorCode SNESTestFunction(SNES);
901 
902 PETSC_EXTERN PetscErrorCode SNESSetDM(SNES, DM);
903 PETSC_EXTERN PetscErrorCode SNESGetDM(SNES, DM *);
904 PETSC_EXTERN PetscErrorCode SNESSetNPC(SNES, SNES);
905 PETSC_EXTERN PetscErrorCode SNESGetNPC(SNES, SNES *);
906 PETSC_EXTERN PetscErrorCode SNESHasNPC(SNES, PetscBool *);
907 PETSC_EXTERN PetscErrorCode SNESApplyNPC(SNES, Vec, Vec, Vec);
908 PETSC_EXTERN PetscErrorCode SNESGetNPCFunction(SNES, Vec, PetscReal *);
909 PETSC_EXTERN PetscErrorCode SNESComputeFunctionDefaultNPC(SNES, Vec, Vec);
910 PETSC_EXTERN PetscErrorCode SNESSetNPCSide(SNES, PCSide);
911 PETSC_EXTERN PetscErrorCode SNESGetNPCSide(SNES, PCSide *);
912 PETSC_EXTERN PetscErrorCode SNESSetLineSearch(SNES, SNESLineSearch);
913 PETSC_EXTERN PetscErrorCode SNESGetLineSearch(SNES, SNESLineSearch *);
914 
915 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESGetLineSearch()", ) static inline PetscErrorCode SNESGetSNESLineSearch(SNES snes, SNESLineSearch *ls)
916 {
917   return SNESGetLineSearch(snes, ls);
918 }
919 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESSetLineSearch()", ) static inline PetscErrorCode SNESSetSNESLineSearch(SNES snes, SNESLineSearch ls)
920 {
921   return SNESSetLineSearch(snes, ls);
922 }
923 
924 PETSC_EXTERN PetscErrorCode SNESSetUpMatrices(SNES);
925 PETSC_EXTERN PetscErrorCode DMSNESSetFunction(DM, SNESFunctionFn *, void *);
926 PETSC_EXTERN PetscErrorCode DMSNESGetFunction(DM, SNESFunctionFn **, void **);
927 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionContextDestroy(DM, PetscErrorCode (*)(void *));
928 PETSC_EXTERN PetscErrorCode DMSNESSetMFFunction(DM, SNESFunctionFn *, void *);
929 PETSC_EXTERN PetscErrorCode DMSNESSetNGS(DM, SNESNGSFn *, void *);
930 PETSC_EXTERN PetscErrorCode DMSNESGetNGS(DM, SNESNGSFn **, void **);
931 PETSC_EXTERN PetscErrorCode DMSNESSetJacobian(DM, SNESJacobianFn *, void *);
932 PETSC_EXTERN PetscErrorCode DMSNESGetJacobian(DM, SNESJacobianFn **, void **);
933 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianContextDestroy(DM, PetscErrorCode (*)(void *));
934 PETSC_EXTERN PetscErrorCode DMSNESSetPicard(DM, SNESFunctionFn *, SNESJacobianFn *, void *);
935 PETSC_EXTERN PetscErrorCode DMSNESGetPicard(DM, SNESFunctionFn **, SNESJacobianFn **, void **);
936 PETSC_EXTERN PetscErrorCode DMSNESSetObjective(DM, SNESObjectiveFn *, void *);
937 PETSC_EXTERN PetscErrorCode DMSNESGetObjective(DM, SNESObjectiveFn **, void **);
938 PETSC_EXTERN PetscErrorCode DMCopyDMSNES(DM, DM);
939 
940 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionFn)(DMDALocalInfo *, void *, void *, void *);
941 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianFn)(DMDALocalInfo *, void *, Mat, Mat, void *);
942 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveFn)(DMDALocalInfo *, void *, PetscReal *, void *);
943 
944 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionVecFn)(DMDALocalInfo *, Vec, Vec, void *);
945 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianVecFn)(DMDALocalInfo *, Vec, Mat, Mat, void *);
946 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveVecFn)(DMDALocalInfo *, Vec, PetscReal *, void *);
947 
948 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocal(DM, InsertMode, DMDASNESFunctionFn *, void *);
949 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocal(DM, DMDASNESJacobianFn *, void *);
950 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocal(DM, DMDASNESObjectiveFn *, void *);
951 PETSC_EXTERN PetscErrorCode DMDASNESSetPicardLocal(DM, InsertMode, DMDASNESFunctionFn *, DMDASNESJacobianFn, void *);
952 
953 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocalVec(DM, InsertMode, DMDASNESFunctionVecFn *, void *);
954 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocalVec(DM, DMDASNESJacobianVecFn *, void *);
955 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocalVec(DM, DMDASNESObjectiveVecFn *, void *);
956 
957 PETSC_EXTERN PetscErrorCode DMSNESSetBoundaryLocal(DM, PetscErrorCode (*)(DM, Vec, void *), void *);
958 PETSC_EXTERN PetscErrorCode DMSNESSetObjectiveLocal(DM, PetscErrorCode (*)(DM, Vec, PetscReal *, void *), void *);
959 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionLocal(DM, PetscErrorCode (*)(DM, Vec, Vec, void *), void *);
960 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianLocal(DM, PetscErrorCode (*)(DM, Vec, Mat, Mat, void *), void *);
961 PETSC_EXTERN PetscErrorCode DMSNESGetBoundaryLocal(DM, PetscErrorCode (**)(DM, Vec, void *), void **);
962 PETSC_EXTERN PetscErrorCode DMSNESGetObjectiveLocal(DM, PetscErrorCode (**)(DM, Vec, PetscReal *, void *), void **);
963 PETSC_EXTERN PetscErrorCode DMSNESGetFunctionLocal(DM, PetscErrorCode (**)(DM, Vec, Vec, void *), void **);
964 PETSC_EXTERN PetscErrorCode DMSNESGetJacobianLocal(DM, PetscErrorCode (**)(DM, Vec, Mat, Mat, void *), void **);
965 
966 /* Routines for Multiblock solver */
967 PETSC_EXTERN PetscErrorCode SNESMultiblockSetFields(SNES, const char[], PetscInt, const PetscInt *);
968 PETSC_EXTERN PetscErrorCode SNESMultiblockSetIS(SNES, const char[], IS);
969 PETSC_EXTERN PetscErrorCode SNESMultiblockSetBlockSize(SNES, PetscInt);
970 PETSC_EXTERN PetscErrorCode SNESMultiblockSetType(SNES, PCCompositeType);
971 PETSC_EXTERN PetscErrorCode SNESMultiblockGetSubSNES(SNES, PetscInt *, SNES *[]);
972 
973 /*J
974    SNESMSType - String with the name of a PETSc `SNESMS` method.
975 
976    Level: intermediate
977 
978 .seealso: [](ch_snes), `SNESMS`, `SNESMSGetType()`, `SNESMSSetType()`, `SNES`
979 J*/
980 typedef const char *SNESMSType;
981 #define SNESMSM62       "m62"
982 #define SNESMSEULER     "euler"
983 #define SNESMSJAMESON83 "jameson83"
984 #define SNESMSVLTP11    "vltp11"
985 #define SNESMSVLTP21    "vltp21"
986 #define SNESMSVLTP31    "vltp31"
987 #define SNESMSVLTP41    "vltp41"
988 #define SNESMSVLTP51    "vltp51"
989 #define SNESMSVLTP61    "vltp61"
990 
991 PETSC_EXTERN PetscErrorCode SNESMSRegister(SNESMSType, PetscInt, PetscInt, PetscReal, const PetscReal[], const PetscReal[], const PetscReal[]);
992 PETSC_EXTERN PetscErrorCode SNESMSRegisterAll(void);
993 PETSC_EXTERN PetscErrorCode SNESMSGetType(SNES, SNESMSType *);
994 PETSC_EXTERN PetscErrorCode SNESMSSetType(SNES, SNESMSType);
995 PETSC_EXTERN PetscErrorCode SNESMSGetDamping(SNES, PetscReal *);
996 PETSC_EXTERN PetscErrorCode SNESMSSetDamping(SNES, PetscReal);
997 PETSC_EXTERN PetscErrorCode SNESMSFinalizePackage(void);
998 PETSC_EXTERN PetscErrorCode SNESMSInitializePackage(void);
999 PETSC_EXTERN PetscErrorCode SNESMSRegisterDestroy(void);
1000 
1001 /*MC
1002    SNESNGMRESRestartType - the restart approach used by `SNESNGMRES`
1003 
1004   Values:
1005 +   `SNES_NGMRES_RESTART_NONE`       - never restart
1006 .   `SNES_NGMRES_RESTART_DIFFERENCE` - restart based upon difference criteria
1007 -   `SNES_NGMRES_RESTART_PERIODIC`   - restart after a fixed number of iterations
1008 
1009   Options Database Keys:
1010 + -snes_ngmres_restart_type <difference,periodic,none> - set the restart type
1011 - -snes_ngmres_restart <30>                            - sets the number of iterations before restart for periodic
1012 
1013    Level: intermediate
1014 
1015 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1016           `SNESNGMRESGetRestartType()`, `SNESNGMRESSelectType`
1017 M*/
1018 typedef enum {
1019   SNES_NGMRES_RESTART_NONE       = 0,
1020   SNES_NGMRES_RESTART_PERIODIC   = 1,
1021   SNES_NGMRES_RESTART_DIFFERENCE = 2
1022 } SNESNGMRESRestartType;
1023 PETSC_EXTERN const char *const SNESNGMRESRestartTypes[];
1024 
1025 /*MC
1026    SNESNGMRESSelectType - the approach used by `SNESNGMRES` to determine how the candidate solution and
1027   combined solution are used to create the next iterate.
1028 
1029    Values:
1030 +   `SNES_NGMRES_SELECT_NONE`       - choose the combined solution all the time
1031 .   `SNES_NGMRES_SELECT_DIFFERENCE` - choose based upon the selection criteria
1032 -   `SNES_NGMRES_SELECT_LINESEARCH` - choose based upon line search combination
1033 
1034   Options Database Key:
1035 . -snes_ngmres_select_type<difference,none,linesearch> - select type
1036 
1037    Level: intermediate
1038 
1039 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1040           `SNESNGMRESGetRestartType()`, `SNESNGMRESRestartType`
1041 M*/
1042 typedef enum {
1043   SNES_NGMRES_SELECT_NONE       = 0,
1044   SNES_NGMRES_SELECT_DIFFERENCE = 1,
1045   SNES_NGMRES_SELECT_LINESEARCH = 2
1046 } SNESNGMRESSelectType;
1047 PETSC_EXTERN const char *const SNESNGMRESSelectTypes[];
1048 
1049 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartType(SNES, SNESNGMRESRestartType);
1050 PETSC_EXTERN PetscErrorCode SNESNGMRESSetSelectType(SNES, SNESNGMRESSelectType);
1051 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartFmRise(SNES, PetscBool);
1052 PETSC_EXTERN PetscErrorCode SNESNGMRESGetRestartFmRise(SNES, PetscBool *);
1053 
1054 /*MC
1055    SNESNCGType - the conjugate update approach for `SNESNCG`
1056 
1057    Values:
1058 +   `SNES_NCG_FR`  - Fletcher-Reeves update
1059 .   `SNES_NCG_PRP` - Polak-Ribiere-Polyak update, the default and the only one that tolerates generalized search directions
1060 .   `SNES_NCG_HS`  - Hestenes-Steifel update
1061 .   `SNES_NCG_DY`  - Dai-Yuan update
1062 -   `SNES_NCG_CD`  - Conjugate Descent update
1063 
1064   Options Database Key:
1065 . -snes_ncg_type<fr,prp,hs,dy,cd> - select type
1066 
1067    Level: intermediate
1068 
1069 .seealso: `SNES, `SNESNCG`, `SNESNCGSetType()`
1070 M*/
1071 typedef enum {
1072   SNES_NCG_FR  = 0,
1073   SNES_NCG_PRP = 1,
1074   SNES_NCG_HS  = 2,
1075   SNES_NCG_DY  = 3,
1076   SNES_NCG_CD  = 4
1077 } SNESNCGType;
1078 PETSC_EXTERN const char *const SNESNCGTypes[];
1079 
1080 PETSC_EXTERN PetscErrorCode SNESNCGSetType(SNES, SNESNCGType);
1081 
1082 /*MC
1083    SNESQNScaleType - the scaling type used by `SNESQN`
1084 
1085    Values:
1086 +   `SNES_QN_SCALE_NONE`     - don't scale the problem
1087 .   `SNES_QN_SCALE_SCALAR`   - use Shanno scaling
1088 .   `SNES_QN_SCALE_DIAGONAL` - scale with a diagonalized BFGS formula (see Gilbert and Lemarechal 1989), available
1089 -   `SNES_QN_SCALE_JACOBIAN` - scale by solving a linear system coming from the Jacobian you provided with `SNESSetJacobian()`
1090                                computed at the first iteration of `SNESQN` and at ever restart.
1091 
1092     Options Database Key:
1093 . -snes_qn_scale_type <diagonal,none,scalar,jacobian> - Scaling type
1094 
1095    Level: intermediate
1096 
1097 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNRestartType`
1098 M*/
1099 typedef enum {
1100   SNES_QN_SCALE_DEFAULT  = 0,
1101   SNES_QN_SCALE_NONE     = 1,
1102   SNES_QN_SCALE_SCALAR   = 2,
1103   SNES_QN_SCALE_DIAGONAL = 3,
1104   SNES_QN_SCALE_JACOBIAN = 4
1105 } SNESQNScaleType;
1106 PETSC_EXTERN const char *const SNESQNScaleTypes[];
1107 
1108 /*MC
1109    SNESQNRestartType - the restart approached used by `SNESQN`
1110 
1111    Values:
1112 +   `SNES_QN_RESTART_NONE`     - never restart
1113 .   `SNES_QN_RESTART_POWELL`   - restart based upon descent criteria
1114 -   `SNES_QN_RESTART_PERIODIC` - restart after a fixed number of iterations
1115 
1116   Options Database Keys:
1117 + -snes_qn_restart_type <powell,periodic,none> - set the restart type
1118 - -snes_qn_m <m>                               - sets the number of stored updates and the restart period for periodic
1119 
1120    Level: intermediate
1121 
1122 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNScaleType`
1123 M*/
1124 typedef enum {
1125   SNES_QN_RESTART_DEFAULT  = 0,
1126   SNES_QN_RESTART_NONE     = 1,
1127   SNES_QN_RESTART_POWELL   = 2,
1128   SNES_QN_RESTART_PERIODIC = 3
1129 } SNESQNRestartType;
1130 PETSC_EXTERN const char *const SNESQNRestartTypes[];
1131 
1132 /*MC
1133    SNESQNType - the type used by `SNESQN`
1134 
1135   Values:
1136 +   `SNES_QN_LBFGS`      - LBFGS variant
1137 .   `SNES_QN_BROYDEN`    - Broyden variant
1138 -   `SNES_QN_BADBROYDEN` - Bad Broyden variant
1139 
1140   Options Database Key:
1141 . -snes_qn_type <lbfgs,broyden,badbroyden> - quasi-Newton type
1142 
1143    Level: intermediate
1144 
1145 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNSetType()`, `SNESQNScaleType`, `SNESQNRestartType`, `SNESQNSetRestartType()`
1146 M*/
1147 typedef enum {
1148   SNES_QN_LBFGS      = 0,
1149   SNES_QN_BROYDEN    = 1,
1150   SNES_QN_BADBROYDEN = 2
1151 } SNESQNType;
1152 PETSC_EXTERN const char *const SNESQNTypes[];
1153 
1154 PETSC_EXTERN PetscErrorCode SNESQNSetType(SNES, SNESQNType);
1155 PETSC_EXTERN PetscErrorCode SNESQNSetScaleType(SNES, SNESQNScaleType);
1156 PETSC_EXTERN PetscErrorCode SNESQNSetRestartType(SNES, SNESQNRestartType);
1157 
1158 PETSC_EXTERN PetscErrorCode SNESNASMGetType(SNES, PCASMType *);
1159 PETSC_EXTERN PetscErrorCode SNESNASMSetType(SNES, PCASMType);
1160 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomains(SNES, PetscInt *, SNES **, VecScatter **, VecScatter **, VecScatter **);
1161 PETSC_EXTERN PetscErrorCode SNESNASMSetSubdomains(SNES, PetscInt, SNES *, VecScatter *, VecScatter *, VecScatter *);
1162 PETSC_EXTERN PetscErrorCode SNESNASMSetDamping(SNES, PetscReal);
1163 PETSC_EXTERN PetscErrorCode SNESNASMGetDamping(SNES, PetscReal *);
1164 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomainVecs(SNES, PetscInt *, Vec **, Vec **, Vec **, Vec **);
1165 PETSC_EXTERN PetscErrorCode SNESNASMSetComputeFinalJacobian(SNES, PetscBool);
1166 PETSC_EXTERN PetscErrorCode SNESNASMGetSNES(SNES, PetscInt, SNES *);
1167 PETSC_EXTERN PetscErrorCode SNESNASMGetNumber(SNES, PetscInt *);
1168 PETSC_EXTERN PetscErrorCode SNESNASMSetWeight(SNES, Vec);
1169 
1170 typedef enum {
1171   SNES_COMPOSITE_ADDITIVE,
1172   SNES_COMPOSITE_MULTIPLICATIVE,
1173   SNES_COMPOSITE_ADDITIVEOPTIMAL
1174 } SNESCompositeType;
1175 PETSC_EXTERN const char *const SNESCompositeTypes[];
1176 
1177 PETSC_EXTERN PetscErrorCode SNESCompositeSetType(SNES, SNESCompositeType);
1178 PETSC_EXTERN PetscErrorCode SNESCompositeAddSNES(SNES, SNESType);
1179 PETSC_EXTERN PetscErrorCode SNESCompositeGetSNES(SNES, PetscInt, SNES *);
1180 PETSC_EXTERN PetscErrorCode SNESCompositeGetNumber(SNES, PetscInt *);
1181 PETSC_EXTERN PetscErrorCode SNESCompositeSetDamping(SNES, PetscInt, PetscReal);
1182 
1183 PETSC_EXTERN PetscErrorCode SNESPatchSetDiscretisationInfo(SNES, PetscInt, DM *, PetscInt *, PetscInt *, const PetscInt **, const PetscInt *, PetscInt, const PetscInt *, PetscInt, const PetscInt *);
1184 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeOperator(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Mat, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1185 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeFunction(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Vec, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1186 PETSC_EXTERN PetscErrorCode SNESPatchSetConstructType(SNES, PCPatchConstructType, PetscErrorCode (*func)(PC, PetscInt *, IS **, IS *, void *), void *);
1187 PETSC_EXTERN PetscErrorCode SNESPatchSetCellNumbering(SNES, PetscSection);
1188 
1189 /*E
1190     SNESFASType - Determines the type of nonlinear multigrid method that is run.
1191 
1192    Values:
1193 +  `SNES_FAS_MULTIPLICATIVE` (default) - traditional V or W cycle as determined by `SNESFASSetCycles()`
1194 .  `SNES_FAS_ADDITIVE`                 - additive FAS cycle
1195 .  `SNES_FAS_FULL`                     - full FAS cycle
1196 -  `SNES_FAS_KASKADE`                  - Kaskade FAS cycle
1197 
1198    Level: beginner
1199 
1200 .seealso: [](ch_snes), `SNESFAS`, `PCMGSetType()`, `PCMGType`
1201 E*/
1202 typedef enum {
1203   SNES_FAS_MULTIPLICATIVE,
1204   SNES_FAS_ADDITIVE,
1205   SNES_FAS_FULL,
1206   SNES_FAS_KASKADE
1207 } SNESFASType;
1208 PETSC_EXTERN const char *const SNESFASTypes[];
1209 
1210 /* called on the finest level FAS instance*/
1211 PETSC_EXTERN PetscErrorCode SNESFASSetType(SNES, SNESFASType);
1212 PETSC_EXTERN PetscErrorCode SNESFASGetType(SNES, SNESFASType *);
1213 PETSC_EXTERN PetscErrorCode SNESFASSetLevels(SNES, PetscInt, MPI_Comm *);
1214 PETSC_EXTERN PetscErrorCode SNESFASGetLevels(SNES, PetscInt *);
1215 PETSC_EXTERN PetscErrorCode SNESFASGetCycleSNES(SNES, PetscInt, SNES *);
1216 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothUp(SNES, PetscInt);
1217 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothDown(SNES, PetscInt);
1218 PETSC_EXTERN PetscErrorCode SNESFASSetCycles(SNES, PetscInt);
1219 PETSC_EXTERN PetscErrorCode SNESFASSetMonitor(SNES, PetscViewerAndFormat *, PetscBool);
1220 PETSC_EXTERN PetscErrorCode SNESFASSetLog(SNES, PetscBool);
1221 
1222 PETSC_EXTERN PetscErrorCode SNESFASSetGalerkin(SNES, PetscBool);
1223 PETSC_EXTERN PetscErrorCode SNESFASGetGalerkin(SNES, PetscBool *);
1224 PETSC_EXTERN PetscErrorCode SNESFASGalerkinFunctionDefault(SNES, Vec, Vec, void *);
1225 
1226 /* called on any level -- "Cycle" FAS instance */
1227 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmoother(SNES, SNES *);
1228 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherUp(SNES, SNES *);
1229 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherDown(SNES, SNES *);
1230 PETSC_EXTERN PetscErrorCode SNESFASCycleGetCorrection(SNES, SNES *);
1231 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInterpolation(SNES, Mat *);
1232 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRestriction(SNES, Mat *);
1233 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInjection(SNES, Mat *);
1234 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRScale(SNES, Vec *);
1235 PETSC_EXTERN PetscErrorCode SNESFASCycleSetCycles(SNES, PetscInt);
1236 PETSC_EXTERN PetscErrorCode SNESFASCycleIsFine(SNES, PetscBool *);
1237 
1238 /* called on the (outer) finest level FAS to set/get parameters on any level instance */
1239 PETSC_EXTERN PetscErrorCode SNESFASSetInterpolation(SNES, PetscInt, Mat);
1240 PETSC_EXTERN PetscErrorCode SNESFASGetInterpolation(SNES, PetscInt, Mat *);
1241 PETSC_EXTERN PetscErrorCode SNESFASSetRestriction(SNES, PetscInt, Mat);
1242 PETSC_EXTERN PetscErrorCode SNESFASGetRestriction(SNES, PetscInt, Mat *);
1243 PETSC_EXTERN PetscErrorCode SNESFASSetInjection(SNES, PetscInt, Mat);
1244 PETSC_EXTERN PetscErrorCode SNESFASGetInjection(SNES, PetscInt, Mat *);
1245 PETSC_EXTERN PetscErrorCode SNESFASSetRScale(SNES, PetscInt, Vec);
1246 PETSC_EXTERN PetscErrorCode SNESFASGetRScale(SNES, PetscInt, Vec *);
1247 PETSC_EXTERN PetscErrorCode SNESFASSetContinuation(SNES, PetscBool);
1248 
1249 PETSC_EXTERN PetscErrorCode SNESFASGetSmoother(SNES, PetscInt, SNES *);
1250 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherUp(SNES, PetscInt, SNES *);
1251 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherDown(SNES, PetscInt, SNES *);
1252 PETSC_EXTERN PetscErrorCode SNESFASGetCoarseSolve(SNES, SNES *);
1253 
1254 /* parameters for full FAS */
1255 PETSC_EXTERN PetscErrorCode SNESFASFullSetDownSweep(SNES, PetscBool);
1256 PETSC_EXTERN PetscErrorCode SNESFASCreateCoarseVec(SNES, Vec *);
1257 PETSC_EXTERN PetscErrorCode SNESFASRestrict(SNES, Vec, Vec);
1258 PETSC_EXTERN PetscErrorCode SNESFASFullSetTotal(SNES, PetscBool);
1259 PETSC_EXTERN PetscErrorCode SNESFASFullGetTotal(SNES, PetscBool *);
1260 
1261 PETSC_EXTERN PetscErrorCode DMSNESCheckDiscretization(SNES, DM, PetscReal, Vec, PetscReal, PetscReal[]);
1262 PETSC_EXTERN PetscErrorCode DMSNESCheckResidual(SNES, DM, Vec, PetscReal, PetscReal *);
1263 PETSC_EXTERN PetscErrorCode DMSNESCheckJacobian(SNES, DM, Vec, PetscReal, PetscBool *, PetscReal *);
1264 PETSC_EXTERN PetscErrorCode DMSNESCheckFromOptions(SNES, Vec);
1265 PETSC_EXTERN PetscErrorCode DMSNESComputeJacobianAction(DM, Vec, Vec, Vec, void *);
1266 PETSC_EXTERN PetscErrorCode DMSNESCreateJacobianMF(DM, Vec, void *, Mat *);
1267