xref: /petsc/include/petscsnes.h (revision a29dfd43bb0c77e2653d3bfa2c953f902720a6d2)
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 
44 /* Logging support */
45 PETSC_EXTERN PetscClassId SNES_CLASSID;
46 PETSC_EXTERN PetscClassId DMSNES_CLASSID;
47 
48 PETSC_EXTERN PetscErrorCode SNESInitializePackage(void);
49 PETSC_EXTERN PetscErrorCode SNESFinalizePackage(void);
50 
51 PETSC_EXTERN PetscErrorCode SNESCreate(MPI_Comm, SNES *);
52 PETSC_EXTERN PetscErrorCode SNESParametersInitialize(SNES);
53 PETSC_EXTERN PetscErrorCode SNESReset(SNES);
54 PETSC_EXTERN PetscErrorCode SNESDestroy(SNES *);
55 PETSC_EXTERN PetscErrorCode SNESSetType(SNES, SNESType);
56 PETSC_EXTERN PetscErrorCode SNESMonitor(SNES, PetscInt, PetscReal);
57 PETSC_EXTERN PetscErrorCode SNESMonitorSet(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *), void *, PetscErrorCode (*)(void **));
58 PETSC_EXTERN PetscErrorCode SNESMonitorSetFromOptions(SNES, const char[], const char[], const char[], PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscViewerAndFormat *), PetscErrorCode (*)(SNES, PetscViewerAndFormat *));
59 PETSC_EXTERN PetscErrorCode SNESMonitorCancel(SNES);
60 PETSC_EXTERN PetscErrorCode SNESMonitorSAWs(SNES, PetscInt, PetscReal, void *);
61 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsCreate(SNES, void **);
62 PETSC_EXTERN PetscErrorCode SNESMonitorSAWsDestroy(void **);
63 PETSC_EXTERN PetscErrorCode SNESSetConvergenceHistory(SNES, PetscReal[], PetscInt[], PetscInt, PetscBool);
64 PETSC_EXTERN PetscErrorCode SNESGetConvergenceHistory(SNES, PetscReal *[], PetscInt *[], PetscInt *);
65 PETSC_EXTERN PetscErrorCode SNESSetUp(SNES);
66 PETSC_EXTERN PetscErrorCode SNESSolve(SNES, Vec, Vec);
67 PETSC_EXTERN PetscErrorCode SNESSetErrorIfNotConverged(SNES, PetscBool);
68 PETSC_EXTERN PetscErrorCode SNESGetErrorIfNotConverged(SNES, PetscBool *);
69 PETSC_EXTERN PetscErrorCode SNESConverged(SNES, PetscInt, PetscReal, PetscReal, PetscReal);
70 
71 PETSC_EXTERN PetscErrorCode SNESSetWorkVecs(SNES, PetscInt);
72 
73 PETSC_EXTERN PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*)(SNES));
74 
75 PETSC_EXTERN PetscErrorCode SNESRegister(const char[], PetscErrorCode (*)(SNES));
76 
77 PETSC_EXTERN PetscErrorCode SNESGetKSP(SNES, KSP *);
78 PETSC_EXTERN PetscErrorCode SNESSetKSP(SNES, KSP);
79 PETSC_EXTERN PetscErrorCode SNESSetSolution(SNES, Vec);
80 PETSC_EXTERN PetscErrorCode SNESGetSolution(SNES, Vec *);
81 PETSC_EXTERN PetscErrorCode SNESGetSolutionUpdate(SNES, Vec *);
82 PETSC_EXTERN PetscErrorCode SNESGetRhs(SNES, Vec *);
83 PETSC_EXTERN PetscErrorCode SNESView(SNES, PetscViewer);
84 PETSC_EXTERN PetscErrorCode SNESLoad(SNES, PetscViewer);
85 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewSet(SNES, PetscErrorCode (*)(SNES, void *), void *, PetscErrorCode (*)(void **));
86 PETSC_EXTERN PetscErrorCode SNESViewFromOptions(SNES, PetscObject, const char[]);
87 PETSC_EXTERN PetscErrorCode SNESConvergedReasonView(SNES, PetscViewer);
88 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewFromOptions(SNES);
89 PETSC_EXTERN PetscErrorCode SNESConvergedReasonViewCancel(SNES);
90 
91 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonView()", ) static inline PetscErrorCode SNESReasonView(SNES snes, PetscViewer v)
92 {
93   return SNESConvergedReasonView(snes, v);
94 }
95 PETSC_DEPRECATED_FUNCTION(3, 14, 0, "SNESConvergedReasonViewFromOptions()", ) static inline PetscErrorCode SNESReasonViewFromOptions(SNES snes)
96 {
97   return SNESConvergedReasonViewFromOptions(snes);
98 }
99 
100 #define SNES_FILE_CLASSID 1211224
101 
102 PETSC_EXTERN PetscErrorCode SNESSetOptionsPrefix(SNES, const char[]);
103 PETSC_EXTERN PetscErrorCode SNESAppendOptionsPrefix(SNES, const char[]);
104 PETSC_EXTERN PetscErrorCode SNESGetOptionsPrefix(SNES, const char *[]);
105 PETSC_EXTERN PetscErrorCode SNESSetFromOptions(SNES);
106 PETSC_EXTERN PetscErrorCode SNESResetFromOptions(SNES);
107 
108 PETSC_EXTERN PetscErrorCode SNESSetUseMatrixFree(SNES, PetscBool, PetscBool);
109 PETSC_EXTERN PetscErrorCode SNESGetUseMatrixFree(SNES, PetscBool *, PetscBool *);
110 PETSC_EXTERN PetscErrorCode MatCreateSNESMF(SNES, Mat *);
111 PETSC_EXTERN PetscErrorCode MatSNESMFGetSNES(Mat, SNES *);
112 PETSC_EXTERN PetscErrorCode MatSNESMFSetReuseBase(Mat, PetscBool);
113 PETSC_EXTERN PetscErrorCode MatSNESMFGetReuseBase(Mat, PetscBool *);
114 PETSC_EXTERN PetscErrorCode MatMFFDComputeJacobian(SNES, Vec, Mat, Mat, void *);
115 PETSC_EXTERN PetscErrorCode MatCreateSNESMFMore(SNES, Vec, Mat *);
116 PETSC_EXTERN PetscErrorCode MatSNESMFMoreSetParameters(Mat, PetscReal, PetscReal, PetscReal);
117 
118 PETSC_EXTERN PetscErrorCode SNESGetType(SNES, SNESType *);
119 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultSetUp(SNES, PetscViewerAndFormat *);
120 PETSC_EXTERN PetscErrorCode SNESMonitorDefault(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
121 PETSC_EXTERN PetscErrorCode SNESMonitorScaling(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
122 PETSC_EXTERN PetscErrorCode SNESMonitorRange(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
123 PETSC_EXTERN PetscErrorCode SNESMonitorRatio(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
124 PETSC_EXTERN PetscErrorCode SNESMonitorRatioSetUp(SNES, PetscViewerAndFormat *);
125 PETSC_EXTERN PetscErrorCode SNESMonitorSolution(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
126 PETSC_EXTERN PetscErrorCode SNESMonitorResidual(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
127 PETSC_EXTERN PetscErrorCode SNESMonitorSolutionUpdate(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
128 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultShort(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
129 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultField(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
130 PETSC_EXTERN PetscErrorCode SNESMonitorJacUpdateSpectrum(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
131 PETSC_EXTERN PetscErrorCode SNESMonitorFields(SNES, PetscInt, PetscReal, PetscViewerAndFormat *);
132 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidual(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
133 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLG(KSP, PetscInt, PetscReal, PetscViewerAndFormat *);
134 PETSC_EXTERN PetscErrorCode KSPMonitorSNESResidualDrawLGCreate(PetscViewer, PetscViewerFormat, void *, PetscViewerAndFormat **);
135 
136 PETSC_EXTERN PetscErrorCode SNESSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt, PetscInt);
137 PETSC_EXTERN PetscErrorCode SNESSetDivergenceTolerance(SNES, PetscReal);
138 PETSC_EXTERN PetscErrorCode SNESGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *, PetscInt *);
139 PETSC_EXTERN PetscErrorCode SNESGetDivergenceTolerance(SNES, PetscReal *);
140 PETSC_EXTERN PetscErrorCode SNESSetTrustRegionTolerance(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 PetscErrorCode SNESNewtonTRDCGetRhoFlag(SNES, PetscBool *);
198 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPreCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, PetscBool *, void *), void *ctx);
199 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPreCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, PetscBool *, void *), void **ctx);
200 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCSetPostCheck(SNES, PetscErrorCode (*)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
201 PETSC_EXTERN PetscErrorCode SNESNewtonTRDCGetPostCheck(SNES, PetscErrorCode (**)(SNES, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
202 
203 PETSC_EXTERN PetscErrorCode SNESGetNonlinearStepFailures(SNES, PetscInt *);
204 PETSC_EXTERN PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES, PetscInt);
205 PETSC_EXTERN PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES, PetscInt *);
206 PETSC_EXTERN PetscErrorCode SNESGetNumberFunctionEvals(SNES, PetscInt *);
207 
208 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditioner(SNES, PetscInt);
209 PETSC_EXTERN PetscErrorCode SNESGetLagPreconditioner(SNES, PetscInt *);
210 PETSC_EXTERN PetscErrorCode SNESSetLagJacobian(SNES, PetscInt);
211 PETSC_EXTERN PetscErrorCode SNESGetLagJacobian(SNES, PetscInt *);
212 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditionerPersists(SNES, PetscBool);
213 PETSC_EXTERN PetscErrorCode SNESSetLagJacobianPersists(SNES, PetscBool);
214 PETSC_EXTERN PetscErrorCode SNESSetGridSequence(SNES, PetscInt);
215 PETSC_EXTERN PetscErrorCode SNESGetGridSequence(SNES, PetscInt *);
216 
217 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveIterations(SNES, PetscInt *);
218 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveFailures(SNES, PetscInt *);
219 PETSC_EXTERN PetscErrorCode SNESSetMaxLinearSolveFailures(SNES, PetscInt);
220 PETSC_EXTERN PetscErrorCode SNESGetMaxLinearSolveFailures(SNES, PetscInt *);
221 PETSC_EXTERN PetscErrorCode SNESSetCountersReset(SNES, PetscBool);
222 
223 PETSC_EXTERN PetscErrorCode SNESKSPSetUseEW(SNES, PetscBool);
224 PETSC_EXTERN PetscErrorCode SNESKSPGetUseEW(SNES, PetscBool *);
225 PETSC_EXTERN PetscErrorCode SNESKSPSetParametersEW(SNES, PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal);
226 PETSC_EXTERN PetscErrorCode SNESKSPGetParametersEW(SNES, PetscInt *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *);
227 
228 #include <petscdrawtypes.h>
229 PETSC_EXTERN PetscErrorCode SNESMonitorLGRange(SNES, PetscInt, PetscReal, void *);
230 
231 PETSC_EXTERN PetscErrorCode SNESSetApplicationContext(SNES, void *);
232 PETSC_EXTERN PetscErrorCode SNESGetApplicationContext(SNES, void *);
233 PETSC_EXTERN PetscErrorCode SNESSetComputeApplicationContext(SNES, PetscErrorCode (*)(SNES, void **), PetscErrorCode (*)(void **));
234 
235 PETSC_EXTERN PetscErrorCode SNESPythonSetType(SNES, const char[]);
236 PETSC_EXTERN PetscErrorCode SNESPythonGetType(SNES, const char *[]);
237 
238 PETSC_EXTERN PetscErrorCode SNESSetFunctionDomainError(SNES);
239 PETSC_EXTERN PetscErrorCode SNESGetFunctionDomainError(SNES, PetscBool *);
240 PETSC_EXTERN PetscErrorCode SNESGetJacobianDomainError(SNES, PetscBool *);
241 PETSC_EXTERN PetscErrorCode SNESSetJacobianDomainError(SNES);
242 PETSC_EXTERN PetscErrorCode SNESSetCheckJacobianDomainError(SNES, PetscBool);
243 PETSC_EXTERN PetscErrorCode SNESGetCheckJacobianDomainError(SNES, PetscBool *);
244 
245 #define SNES_CONVERGED_TR_DELTA_DEPRECATED SNES_CONVERGED_TR_DELTA PETSC_DEPRECATED_ENUM(3, 12, 0, "SNES_DIVERGED_TR_DELTA", )
246 /*E
247     SNESConvergedReason - reason a `SNESSolve()` was determined to have converged or diverged
248 
249    Values:
250 +  `SNES_CONVERGED_FNORM_ABS`      - 2-norm(F) <= abstol
251 .  `SNES_CONVERGED_FNORM_RELATIVE` - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
252 .  `SNES_CONVERGED_SNORM_RELATIVE` - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
253 .  `SNES_DIVERGED_FUNCTION_COUNT`  - The user provided function has been called more times than the maximum set in `SNESSetTolerances()`
254 .  `SNES_DIVERGED_DTOL`            - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
255 .  `SNES_DIVERGED_FNORM_NAN`       - the 2-norm of the current function evaluation is not-a-number (NaN), this
256                                      is usually caused by a division of 0 by 0.
257 .  `SNES_DIVERGED_MAX_IT`          - `SNESSolve()` has reached the maximum number of iterations requested
258 .  `SNES_DIVERGED_LINE_SEARCH`     - The line search has failed. This only occurs for `SNES` solvers that use a line search
259 .  `SNES_DIVERGED_LOCAL_MIN`       - the algorithm seems to have stagnated at a local minimum that is not zero.
260 -  `SNES_CONERGED_ITERATING`       - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
261 
262    Level: beginner
263 
264     Notes:
265    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
266    testing with `-pc_type lu` to eliminate the linear solver as the cause of the problem).
267 
268    `SNES_DIVERGED_LOCAL_MIN` can only occur when using the line-search variant of `SNES`.
269    The line search wants to minimize Q(alpha) = 1/2 || F(x + alpha s) ||^2_2  this occurs
270    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
271    you get Q'(alpha) = -F(x)^T F'(x)^(-1)^T F'(x+alpha s)F(x+alpha s); when alpha = 0
272    Q'(0) = - ||F(x)||^2_2 which is always NEGATIVE if F'(x) is invertible. This means the Newton
273    direction is a descent direction and the line search should succeed if alpha is small enough.
274 
275    If F'(x) is NOT invertible AND F'(x)^T F(x) = 0 then Q'(0) = 0 and the Newton direction
276    is NOT a descent direction so the line search will fail. All one can do at this point
277    is change the initial guess and try again.
278 
279    An alternative explanation: Newton's method can be regarded as replacing the function with
280    its linear approximation and minimizing the 2-norm of that. That is F(x+s) approx F(x) + F'(x)s
281    so we minimize || F(x) + F'(x) s ||^2_2; do this using Least Squares. If F'(x) is invertible then
282    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
283    exists a nontrivial (that is F'(x)s != 0) solution to the equation and this direction is
284    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)
285    = - (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
286    and F'(x)^T F'(x) has no negative eigenvalues Q'(0) < 0 so s is a descent direction and the line
287    search should succeed for small enough alpha.
288 
289    Note that this RARELY happens in practice. Far more likely the linear system is not being solved
290    (well enough?) or the Jacobian is wrong.
291 
292    `SNES_DIVERGED_MAX_IT` means that the solver reached the maximum number of iterations without satisfying any
293    convergence criteria. `SNES_CONVERGED_ITS` means that `SNESConvergedSkip()` was chosen as the convergence test;
294    thus the usual convergence criteria have not been checked and may or may not be satisfied.
295 
296 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`, `SNESSetTolerances()`
297 E*/
298 typedef enum {                       /* converged */
299   SNES_CONVERGED_FNORM_ABS      = 2, /* ||F|| < atol */
300   SNES_CONVERGED_FNORM_RELATIVE = 3, /* ||F|| < rtol*||F_initial|| */
301   SNES_CONVERGED_SNORM_RELATIVE = 4, /* Newton computed step size small; || delta x || < stol || x ||*/
302   SNES_CONVERGED_ITS            = 5, /* maximum iterations reached */
303   SNES_BREAKOUT_INNER_ITER      = 6, /* Flag to break out of inner loop after checking custom convergence. */
304                                      /* it is used in multi-phase flow when state changes */
305   /* diverged */
306   SNES_DIVERGED_FUNCTION_DOMAIN      = -1, /* the new x location passed the function is not in the domain of F */
307   SNES_DIVERGED_FUNCTION_COUNT       = -2,
308   SNES_DIVERGED_LINEAR_SOLVE         = -3, /* the linear solve failed */
309   SNES_DIVERGED_FNORM_NAN            = -4,
310   SNES_DIVERGED_MAX_IT               = -5,
311   SNES_DIVERGED_LINE_SEARCH          = -6,  /* the line search failed */
312   SNES_DIVERGED_INNER                = -7,  /* inner solve failed */
313   SNES_DIVERGED_LOCAL_MIN            = -8,  /* || J^T b || is small, implies converged to local minimum of F() */
314   SNES_DIVERGED_DTOL                 = -9,  /* || F || > divtol*||F_initial|| */
315   SNES_DIVERGED_JACOBIAN_DOMAIN      = -10, /* Jacobian calculation does not make sense */
316   SNES_DIVERGED_TR_DELTA             = -11,
317   SNES_CONVERGED_TR_DELTA_DEPRECATED = -11,
318 
319   SNES_CONVERGED_ITERATING = 0
320 } SNESConvergedReason;
321 PETSC_EXTERN const char *const *SNESConvergedReasons;
322 
323 /*MC
324    SNES_CONVERGED_FNORM_ABS - 2-norm(F) <= abstol
325 
326    Level: beginner
327 
328 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
329 M*/
330 
331 /*MC
332    SNES_CONVERGED_FNORM_RELATIVE - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
333 
334    Level: beginner
335 
336 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
337 M*/
338 
339 /*MC
340   SNES_CONVERGED_SNORM_RELATIVE - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
341   solution and stol is the 4th argument to `SNESSetTolerances()`
342 
343   Options Database Key:
344   -snes_stol <stol> - the step tolerance
345 
346    Level: beginner
347 
348 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
349 M*/
350 
351 /*MC
352    SNES_DIVERGED_FUNCTION_COUNT - The user provided function has been called more times then the final
353    argument to `SNESSetTolerances()`
354 
355    Level: beginner
356 
357 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
358 M*/
359 
360 /*MC
361    SNES_DIVERGED_DTOL - The norm of the function has increased by a factor of divtol set with `SNESSetDivergenceTolerance()`
362 
363    Level: beginner
364 
365 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESSetDivergenceTolerance()`
366 M*/
367 
368 /*MC
369    SNES_DIVERGED_FNORM_NAN - the 2-norm of the current function evaluation is not-a-number (NaN), this
370    is usually caused by a division of 0 by 0.
371 
372    Level: beginner
373 
374 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
375 M*/
376 
377 /*MC
378    SNES_DIVERGED_MAX_IT - SNESSolve() has reached the maximum number of iterations requested
379 
380    Level: beginner
381 
382 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
383 M*/
384 
385 /*MC
386    SNES_DIVERGED_LINE_SEARCH - The line search has failed. This only occurs for a `SNES` solvers that use a line search
387 
388    Level: beginner
389 
390 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`, `SNESLineSearch`
391 M*/
392 
393 /*MC
394    SNES_DIVERGED_LOCAL_MIN - the algorithm seems to have stagnated at a local minimum that is not zero.
395    See the manual page for `SNESConvergedReason` for more details
396 
397    Level: beginner
398 
399 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
400 M*/
401 
402 /*MC
403    SNES_CONERGED_ITERATING - this only occurs if `SNESGetConvergedReason()` is called during the `SNESSolve()`
404 
405    Level: beginner
406 
407 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `SNESConvergedReason`, `SNESSetTolerances()`
408 M*/
409 
410 PETSC_EXTERN PetscErrorCode SNESSetConvergenceTest(SNES, PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *, PetscErrorCode (*)(void *));
411 PETSC_EXTERN PetscErrorCode SNESConvergedDefault(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
412 PETSC_EXTERN PetscErrorCode SNESConvergedSkip(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
413 PETSC_EXTERN PetscErrorCode SNESConvergedCorrectPressure(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *);
414 PETSC_EXTERN PetscErrorCode SNESGetConvergedReason(SNES, SNESConvergedReason *);
415 PETSC_EXTERN PetscErrorCode SNESGetConvergedReasonString(SNES, const char **);
416 PETSC_EXTERN PetscErrorCode SNESSetConvergedReason(SNES, SNESConvergedReason);
417 
418 PETSC_DEPRECATED_FUNCTION(3, 5, 0, "SNESConvergedSkip()", ) static inline void SNESSkipConverged(void)
419 { /* never called */
420 }
421 #define SNESSkipConverged (SNESSkipConverged, SNESConvergedSkip)
422 
423 /*S
424   SNESInitialGuessFn - A prototype of a `SNES` compute initial guess function that would be passed to `SNESSetComputeInitialGuess()`
425 
426   Calling Sequence:
427 + snes  - `SNES` context
428 . u   - output vector to contain initial guess
429 - ctx - [optional] user-defined function context
430 
431   Level: beginner
432 
433 .seealso: [](ch_snes), `SNES`, `SNESSetComputeInitialGuess()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESFunctionFn`
434 S*/
435 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESInitialGuessFn)(SNES snes, Vec u, void *ctx);
436 
437 /*S
438   SNESFunctionFn - A prototype of a `SNES` evaluation function that would be passed to `SNESSetFunction()`
439 
440   Calling Sequence:
441 + snes  - `SNES` context
442 . u   - input vector
443 . F   - function vector
444 - ctx - [optional] user-defined function context
445 
446   Level: beginner
447 
448 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
449 S*/
450 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESFunctionFn)(SNES snes, Vec u, Vec F, void *ctx);
451 
452 /*S
453   SNESObjectiveFn - A prototype of a `SNES` objective evaluation function that would be passed to `SNESSetObjective()`
454 
455   Calling Sequence:
456 + snes  - `SNES` context
457 . u   - input vector
458 . o   - output value
459 - ctx - [optional] user-defined function context
460 
461   Level: beginner
462 
463 .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`, `SNESNGSFn`
464 S*/
465 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESObjectiveFn)(SNES snes, Vec u, PetscReal *o, void *ctx);
466 
467 /*S
468   SNESJacobianFn - A prototype of a `SNES` Jacobian evaluation function that would be passed to `SNESSetJacobian()`
469 
470   Calling Sequence:
471 + snes   - the `SNES` context obtained from `SNESCreate()`
472 . u    - input vector
473 . Amat - (approximate) Jacobian matrix
474 . Pmat - matrix used to construct the preconditioner, often the same as `Amat`
475 - ctx  - [optional] user-defined context for matrix evaluation routine
476 
477   Level: beginner
478 
479 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESNGSFn`
480 S*/
481 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESJacobianFn)(SNES snes, Vec u, Mat Amat, Mat Pmat, void *ctx);
482 
483 /*S
484   SNESNGSFn - A prototype of a `SNES` nonlinear Gauss-Seidel function that would be passed to `SNESSetNGS()`
485 
486   Calling Sequence:
487 + snes   - the `SNES` context obtained from `SNESCreate()`
488 . u    - the current solution, updated in place
489 . b    - the right-hand side vector (which may be `NULL`)
490 - ctx  - [optional] user-defined context for matrix evaluation routine
491 
492   Level: beginner
493 
494 .seealso: [](ch_snes), `SNES`, `SNESSetJacobian()`, `SNESGetJacobian()`, `SNESFunctionFn`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESJacobianFn`
495 S*/
496 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESNGSFn)(SNES snes, Vec u, Vec b, void *ctx);
497 
498 /*S
499   SNESUpdateFn - A prototype of a `SNES` update function that would be passed to `SNESSetUpdate()`
500 
501   Calling Sequence:
502 + snes - `SNES` context
503 - step - the current iteration index
504 
505   Level: advanced
506 
507 .seealso: [](ch_snes), `SNES`, `SNESSetUpdate()`
508 S*/
509 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESUpdateFn)(SNES snes, PetscInt step);
510 
511 /* --------- Solving systems of nonlinear equations --------------- */
512 PETSC_EXTERN PetscErrorCode SNESSetFunction(SNES, Vec, SNESFunctionFn *, void *);
513 PETSC_EXTERN PetscErrorCode SNESGetFunction(SNES, Vec *, SNESFunctionFn **, void **);
514 PETSC_EXTERN PetscErrorCode SNESComputeFunction(SNES, Vec, Vec);
515 PETSC_EXTERN PetscErrorCode SNESComputeMFFunction(SNES, Vec, Vec);
516 PETSC_EXTERN PetscErrorCode SNESSetInitialFunction(SNES, Vec);
517 
518 PETSC_EXTERN PetscErrorCode SNESSetJacobian(SNES, Mat, Mat, SNESJacobianFn *, void *);
519 PETSC_EXTERN PetscErrorCode SNESGetJacobian(SNES, Mat *, Mat *, SNESJacobianFn **, void **);
520 PETSC_EXTERN SNESFunctionFn SNESObjectiveComputeFunctionDefaultFD;
521 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefault;
522 PETSC_EXTERN SNESJacobianFn SNESComputeJacobianDefaultColor;
523 PETSC_EXTERN PetscErrorCode SNESPruneJacobianColor(SNES, Mat, Mat);
524 PETSC_EXTERN PetscErrorCode SNESSetComputeInitialGuess(SNES, SNESInitialGuessFn *, void *);
525 PETSC_EXTERN PetscErrorCode SNESSetPicard(SNES, Vec, SNESFunctionFn *, Mat, Mat, SNESJacobianFn *, void *);
526 PETSC_EXTERN PetscErrorCode SNESGetPicard(SNES, Vec *, SNESFunctionFn **, Mat *, Mat *, SNESJacobianFn **, void **);
527 PETSC_EXTERN SNESFunctionFn SNESPicardComputeFunction;
528 PETSC_EXTERN SNESFunctionFn SNESPicardComputeMFFunction;
529 PETSC_EXTERN SNESJacobianFn SNESPicardComputeJacobian;
530 
531 PETSC_EXTERN PetscErrorCode SNESSetObjective(SNES, SNESObjectiveFn *, void *);
532 PETSC_EXTERN PetscErrorCode SNESGetObjective(SNES, SNESObjectiveFn **, void **);
533 PETSC_EXTERN PetscErrorCode SNESComputeObjective(SNES, Vec, PetscReal *);
534 
535 PETSC_EXTERN PetscErrorCode SNESSetUpdate(SNES, SNESUpdateFn *);
536 
537 /*E
538    SNESNormSchedule - Frequency with which the norm is computed during a nonliner solve
539 
540    Values:
541 +   `SNES_NORM_DEFAULT`            - use the default behavior for the current `SNESType`
542 .   `SNES_NORM_NONE`               - avoid all norm computations
543 .   `SNES_NORM_ALWAYS`             - compute the norms whenever possible
544 .   `SNES_NORM_INITIAL_ONLY`       - compute the norm only when the algorithm starts
545 .   `SNES_NORM_FINAL_ONLY`         - compute the norm only when the algorithm finishes
546 -   `SNES_NORM_INITIAL_FINAL_ONLY` - compute the norm at the start and end of the algorithm
547 
548    Level: advanced
549 
550    Notes:
551    Support for these is highly dependent on the solver.
552 
553    Some options limit the convergence tests that can be used.
554 
555    The `SNES_NORM_NONE` option is most commonly used when the nonlinear solver is being used as a smoother, for example for `SNESFAS`
556 
557    This is primarily used to turn off extra norm and function computation
558    when the solvers are composed.
559 
560 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
561           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
562 E*/
563 typedef enum {
564   SNES_NORM_DEFAULT            = -1,
565   SNES_NORM_NONE               = 0,
566   SNES_NORM_ALWAYS             = 1,
567   SNES_NORM_INITIAL_ONLY       = 2,
568   SNES_NORM_FINAL_ONLY         = 3,
569   SNES_NORM_INITIAL_FINAL_ONLY = 4
570 } SNESNormSchedule;
571 PETSC_EXTERN const char *const *const SNESNormSchedules;
572 
573 /*MC
574    SNES_NORM_NONE - Don't compute function and its L2 norm when possible
575 
576    Level: advanced
577 
578    Note:
579    This is most useful for stationary solvers with a fixed number of iterations used as smoothers.
580 
581 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_DEFAULT`
582 M*/
583 
584 /*MC
585    SNES_NORM_ALWAYS - Compute the function and its L2 norm at each iteration.
586 
587    Level: advanced
588 
589    Note:
590    Most solvers will use this no matter what norm type is passed to them.
591 
592 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_NONE`
593 M*/
594 
595 /*MC
596    SNES_NORM_INITIAL_ONLY - Compute the function and its L2 at iteration 0, but do not update it.
597 
598    Level: advanced
599 
600    Notes:
601    This method is useful in composed methods, when a true solution might actually be found before `SNESSolve()` is called.
602    This option enables the solve to abort on the zeroth iteration if this is the case.
603 
604    For solvers that require the computation of the L2 norm of the function as part of the method, this merely cancels
605    the norm computation at the last iteration (if possible).
606 
607 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_FINAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
608 M*/
609 
610 /*MC
611    SNES_NORM_FINAL_ONLY - Compute the function and its L2 norm on only the final iteration.
612 
613    Level: advanced
614 
615    Note:
616    For solvers that require the computation of the L2 norm of the function as part of the method, behaves
617    exactly as `SNES_NORM_DEFAULT`.  This method is useful when the function is gotten after `SNESSolve()` and
618    used in subsequent computation for methods that do not need the norm computed during the rest of the
619    solution procedure.
620 
621 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_INITIAL_ONLY`, `SNES_NORM_INITIAL_FINAL_ONLY`
622 M*/
623 
624 /*MC
625    SNES_NORM_INITIAL_FINAL_ONLY - Compute the function and its L2 norm on only the initial and final iterations.
626 
627    Level: advanced
628 
629    Note:
630    This method combines the benefits of `SNES_NORM_INITIAL_ONLY` and `SNES_NORM_FINAL_ONLY`.
631 
632 .seealso: [](ch_snes), `SNESNormSchedule`, `SNES`, `SNESSetNormSchedule()`, `SNES_NORM_SNES_NORM_INITIAL_ONLY`, `SNES_NORM_FINAL_ONLY`
633 M*/
634 
635 PETSC_EXTERN PetscErrorCode SNESSetNormSchedule(SNES, SNESNormSchedule);
636 PETSC_EXTERN PetscErrorCode SNESGetNormSchedule(SNES, SNESNormSchedule *);
637 PETSC_EXTERN PetscErrorCode SNESSetFunctionNorm(SNES, PetscReal);
638 PETSC_EXTERN PetscErrorCode SNESGetFunctionNorm(SNES, PetscReal *);
639 PETSC_EXTERN PetscErrorCode SNESGetUpdateNorm(SNES, PetscReal *);
640 PETSC_EXTERN PetscErrorCode SNESGetSolutionNorm(SNES, PetscReal *);
641 
642 /*E
643    SNESFunctionType - Type of function computed
644 
645    Values:
646 +  `SNES_FUNCTION_DEFAULT`          - the default behavior for the current `SNESType`
647 .  `SNES_FUNCTION_UNPRECONDITIONED` - the original function provided
648 -  `SNES_FUNCTION_PRECONDITIONED`   - the modification of the function by the preconditioner
649 
650    Level: advanced
651 
652    Note:
653    Support for these is dependent on the solver.
654 
655 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPSetNormType()`,
656           `KSPSetConvergenceTest()`, `KSPSetPCSide()`
657 E*/
658 typedef enum {
659   SNES_FUNCTION_DEFAULT          = -1,
660   SNES_FUNCTION_UNPRECONDITIONED = 0,
661   SNES_FUNCTION_PRECONDITIONED   = 1
662 } SNESFunctionType;
663 PETSC_EXTERN const char *const *const SNESFunctionTypes;
664 
665 PETSC_EXTERN PetscErrorCode SNESSetFunctionType(SNES, SNESFunctionType);
666 PETSC_EXTERN PetscErrorCode SNESGetFunctionType(SNES, SNESFunctionType *);
667 
668 PETSC_EXTERN PetscErrorCode SNESSetNGS(SNES, SNESNGSFn *, void *);
669 PETSC_EXTERN PetscErrorCode SNESGetNGS(SNES, SNESNGSFn **, void **);
670 PETSC_EXTERN PetscErrorCode SNESComputeNGS(SNES, Vec, Vec);
671 
672 PETSC_EXTERN PetscErrorCode SNESNGSSetSweeps(SNES, PetscInt);
673 PETSC_EXTERN PetscErrorCode SNESNGSGetSweeps(SNES, PetscInt *);
674 PETSC_EXTERN PetscErrorCode SNESNGSSetTolerances(SNES, PetscReal, PetscReal, PetscReal, PetscInt);
675 PETSC_EXTERN PetscErrorCode SNESNGSGetTolerances(SNES, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
676 
677 PETSC_EXTERN PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES, PetscBool);
678 PETSC_EXTERN PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES, PetscBool *);
679 
680 PETSC_EXTERN PetscErrorCode SNESShellGetContext(SNES, void *);
681 PETSC_EXTERN PetscErrorCode SNESShellSetContext(SNES, void *);
682 PETSC_EXTERN PetscErrorCode SNESShellSetSolve(SNES, PetscErrorCode (*)(SNES, Vec));
683 
684 /* --------- Routines specifically for line search methods --------------- */
685 
686 /*S
687    SNESLineSearch - Abstract PETSc object that manages line-search operations for nonlinear solvers
688 
689    Level: beginner
690 
691 .seealso: [](ch_snes), `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetType()`, `SNES`
692 S*/
693 typedef struct _p_LineSearch *SNESLineSearch;
694 
695 /*J
696    SNESLineSearchType - String with the name of a PETSc line search method `SNESLineSearch`
697 
698    Values:
699 +  `SNESLINESEARCHBASIC`   - (or equivalently `SNESLINESEARCHNONE`) Simple damping line search, defaults to using the full Newton step
700 .  `SNESLINESEARCHBT`      - Backtracking line search over the L2 norm of the function
701 .  `SNESLINESEARCHL2`      - Secant line search over the L2 norm of the function
702 .  `SNESLINESEARCHCP`      - Critical point secant line search assuming F(x) = grad G(x) for some unknown G(x)
703 .  `SNESLINESEARCHNLEQERR` - Affine-covariant error-oriented linesearch
704 -  `SNESLINESEARCHSHELL`   - User provided `SNESLineSearch` implementation
705 
706    Level: beginner
707 
708 .seealso: [](ch_snes), `SNESLineSearch`, `SNESLineSearchSetType()`, `SNES`
709 J*/
710 typedef const char *SNESLineSearchType;
711 #define SNESLINESEARCHBT        "bt"
712 #define SNESLINESEARCHNLEQERR   "nleqerr"
713 #define SNESLINESEARCHBASIC     "basic"
714 #define SNESLINESEARCHNONE      "none"
715 #define SNESLINESEARCHL2        "l2"
716 #define SNESLINESEARCHCP        "cp"
717 #define SNESLINESEARCHSHELL     "shell"
718 #define SNESLINESEARCHNCGLINEAR "ncglinear"
719 
720 PETSC_EXTERN PetscFunctionList SNESList;
721 PETSC_EXTERN PetscClassId      SNESLINESEARCH_CLASSID;
722 PETSC_EXTERN PetscFunctionList SNESLineSearchList;
723 
724 #define SNES_LINESEARCH_ORDER_LINEAR    1
725 #define SNES_LINESEARCH_ORDER_QUADRATIC 2
726 #define SNES_LINESEARCH_ORDER_CUBIC     3
727 
728 /*S
729   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that projects a vector onto the VI bounds, passed to `SNESLineSearchSetVIFunctions()`
730 
731   Calling Sequence:
732 + snes  - `SNES` context
733 - u     - the vector to project to the bounds
734 
735   Level: advanced
736 
737   Note:
738   The deprecated `SNESLineSearchVIProjectFunc` still works as a replacement for `SNESLineSearchVIProjectFn` *.
739 
740 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
741 S*/
742 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVIProjectFn)(SNES snes, Vec u);
743 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVIProjectFn *SNESLineSearchVIProjectFunc; // deprecated
744 
745 /*S
746   SNESLineSearchVIProjectFn - A prototype of a `SNES` function that computes the norm of the active set variables in a vector in a VI solve,
747   passed to `SNESLineSearchSetVIFunctions()`
748 
749   Calling Sequence:
750 + snes  - `SNES` context
751 . f     - the vector to compute the norm of
752 . u     - the current solution, entries that are on the VI bounds are ignored
753 - fnorm - the resulting norm
754 
755   Level: advanced
756 
757   Note:
758   The deprecated `SNESLineSearchVINormFunc` still works as a replacement for `SNESLineSearchVINormFn` *.
759 
760 .seealso: [](ch_snes), `SNES`, `SNESLineSearch`
761 S*/
762 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchVINormFn)(SNES snes, Vec f, Vec u, PetscReal *fnorm);
763 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchVINormFn *SNESLineSearchVINormFunc; // deprecated
764 
765 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchApplyFn)(SNESLineSearch);
766 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchApplyFn *SNESLineSearchApplyFunc; // deprecated
767 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(SNESLineSearchShellApplyFn)(SNESLineSearch, void *);
768 PETSC_EXTERN_TYPEDEF typedef SNESLineSearchShellApplyFn *SNESLineSearchUserFunc; // deprecated
769 
770 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate(MPI_Comm, SNESLineSearch *);
771 PETSC_EXTERN PetscErrorCode SNESLineSearchReset(SNESLineSearch);
772 PETSC_EXTERN PetscErrorCode SNESLineSearchView(SNESLineSearch, PetscViewer);
773 PETSC_EXTERN PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *);
774 PETSC_EXTERN PetscErrorCode SNESLineSearchGetType(SNESLineSearch, SNESLineSearchType *);
775 PETSC_EXTERN PetscErrorCode SNESLineSearchSetType(SNESLineSearch, SNESLineSearchType);
776 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch);
777 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch, PetscErrorCode (*)(SNES, Vec, Vec));
778 PETSC_EXTERN PetscErrorCode SNESLineSearchSetUp(SNESLineSearch);
779 PETSC_EXTERN PetscErrorCode SNESLineSearchApply(SNESLineSearch, Vec, Vec, PetscReal *, Vec);
780 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch, Vec, Vec, PetscBool *);
781 PETSC_EXTERN PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *);
782 PETSC_EXTERN PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch, PetscInt);
783 
784 /* set the functions for precheck and postcheck */
785 
786 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void *ctx);
787 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void *ctx);
788 
789 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void **ctx);
790 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch, PetscErrorCode (**)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx);
791 
792 /* set the functions for VI-specific line search operations */
793 
794 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn *, SNESLineSearchVINormFn *);
795 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFn **, SNESLineSearchVINormFn **);
796 
797 /* pointers to the associated SNES in order to be able to get the function evaluation out */
798 PETSC_EXTERN PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch, SNES);
799 PETSC_EXTERN PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch, SNES *);
800 
801 /* set and get the parameters and vectors */
802 PETSC_EXTERN PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscInt *);
803 PETSC_EXTERN PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscInt);
804 
805 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch, Vec, Vec, PetscBool *, void *);
806 
807 PETSC_EXTERN PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch, PetscReal *);
808 PETSC_EXTERN PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch, PetscReal);
809 
810 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch, PetscReal *);
811 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch, PetscReal);
812 
813 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch, PetscInt *order);
814 PETSC_EXTERN PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch, PetscInt order);
815 
816 /*E
817     SNESLineSearchReason - indication if the line search has succeeded or failed and why
818 
819   Values:
820 +  `SNES_LINESEARCH_SUCCEEDED`       - the line search succeeded
821 .  `SNES_LINESEARCH_FAILED_NANORINF` - a not a number of infinity appeared in the computions
822 .  `SNES_LINESEARCH_FAILED_DOMAIN`   - the function was evaluated outside of its domain, see `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
823 .  `SNES_LINESEARCH_FAILED_REDUCT`   - the linear search failed to get the requested decrease in its norm or objective
824 .  `SNES_LINESEARCH_FAILED_USER`     - used by `SNESLINESEARCHNLEQERR` to indicate the user changed the search direction inappropriately
825 -  `SNES_LINESEARCH_FAILED_FUNCTION` - indicates the maximum number of function evaluations allowed has been surpassed, `SNESConvergedReason` is also
826                                        set to `SNES_DIVERGED_FUNCTION_COUNT`
827 
828    Level: intermediate
829 
830    Developer Note:
831    Some of these reasons overlap with values of `SNESConvergedReason`
832 
833 .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergedReason()`, `KSPConvergedReason`, `SNESSetConvergenceTest()`,
834           `SNESSetFunctionDomainError()` and `SNESSetJacobianDomainError()`
835 E*/
836 typedef enum {
837   SNES_LINESEARCH_SUCCEEDED,
838   SNES_LINESEARCH_FAILED_NANORINF,
839   SNES_LINESEARCH_FAILED_DOMAIN,
840   SNES_LINESEARCH_FAILED_REDUCT, /* INSUFFICIENT REDUCTION */
841   SNES_LINESEARCH_FAILED_USER,
842   SNES_LINESEARCH_FAILED_FUNCTION
843 } SNESLineSearchReason;
844 
845 PETSC_EXTERN PetscErrorCode SNESLineSearchGetReason(SNESLineSearch, SNESLineSearchReason *);
846 PETSC_EXTERN PetscErrorCode SNESLineSearchSetReason(SNESLineSearch, SNESLineSearchReason);
847 
848 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch, Vec *, Vec *, Vec *, Vec *, Vec *);
849 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch, Vec, Vec, Vec, Vec, Vec);
850 
851 PETSC_EXTERN PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *);
852 PETSC_EXTERN PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch, PetscReal, PetscReal, PetscReal);
853 PETSC_EXTERN PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch);
854 PETSC_EXTERN PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch, PetscBool);
855 
856 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitor(SNESLineSearch);
857 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSet(SNESLineSearch, PetscErrorCode (*)(SNESLineSearch, void *), void *, PetscErrorCode (*)(void **));
858 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSetFromOptions(SNESLineSearch, const char[], const char[], const char[], PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *), PetscErrorCode (*)(SNESLineSearch, PetscViewerAndFormat *));
859 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorCancel(SNESLineSearch);
860 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch, PetscViewer);
861 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDefaultMonitor(SNESLineSearch, PetscViewer *);
862 PETSC_EXTERN PetscErrorCode SNESLineSearchMonitorSolutionUpdate(SNESLineSearch, PetscViewerAndFormat *);
863 
864 PETSC_EXTERN PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch, const char prefix[]);
865 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch, const char *prefix[]);
866 
867 /* Shell interface functions */
868 PETSC_EXTERN PetscErrorCode SNESLineSearchShellSetApply(SNESLineSearch, SNESLineSearchShellApplyFn, void *);
869 PETSC_EXTERN PetscErrorCode SNESLineSearchShellGetApply(SNESLineSearch, SNESLineSearchShellApplyFn **, void **);
870 
871 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellSetApply()", ) static inline PetscErrorCode SNESLineSearchShellSetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc f, void *ctx)
872 {
873   return SNESLineSearchShellSetApply(ls, f, ctx);
874 }
875 
876 PETSC_DEPRECATED_FUNCTION(3, 21, 0, "SNESLinesearchShellGetApply()", ) static inline PetscErrorCode SNESLineSearchShellGetUserFunc(SNESLineSearch ls, SNESLineSearchUserFunc *f, void **ctx)
877 {
878   return SNESLineSearchShellGetApply(ls, f, ctx);
879 }
880 
881 /* BT interface functions */
882 PETSC_EXTERN PetscErrorCode SNESLineSearchBTSetAlpha(SNESLineSearch, PetscReal);
883 PETSC_EXTERN PetscErrorCode SNESLineSearchBTGetAlpha(SNESLineSearch, PetscReal *);
884 
885 /*register line search types */
886 PETSC_EXTERN PetscErrorCode SNESLineSearchRegister(const char[], PetscErrorCode (*)(SNESLineSearch));
887 
888 /* Routines for VI solver */
889 PETSC_EXTERN PetscErrorCode SNESVISetVariableBounds(SNES, Vec, Vec);
890 PETSC_EXTERN PetscErrorCode SNESVIGetVariableBounds(SNES, Vec *, Vec *);
891 PETSC_EXTERN PetscErrorCode SNESVISetComputeVariableBounds(SNES, PetscErrorCode (*)(SNES, Vec, Vec));
892 PETSC_EXTERN PetscErrorCode SNESVIGetInactiveSet(SNES, IS *);
893 PETSC_EXTERN PetscErrorCode SNESVIGetActiveSetIS(SNES, Vec, Vec, IS *);
894 PETSC_EXTERN PetscErrorCode SNESVIComputeInactiveSetFnorm(SNES, Vec, Vec, PetscReal *);
895 PETSC_EXTERN PetscErrorCode SNESVISetRedundancyCheck(SNES, PetscErrorCode (*)(SNES, IS, IS *, void *), void *);
896 PETSC_EXTERN PetscErrorCode SNESVIComputeMeritFunction(Vec, PetscReal *, PetscReal *);
897 PETSC_EXTERN PetscErrorCode SNESVIComputeFunction(SNES, Vec, Vec, void *);
898 PETSC_EXTERN PetscErrorCode DMSetVI(DM, IS);
899 PETSC_EXTERN PetscErrorCode DMDestroyVI(DM);
900 
901 PETSC_EXTERN PetscErrorCode SNESTestLocalMin(SNES);
902 
903 /* Should this routine be private? */
904 PETSC_EXTERN PetscErrorCode SNESComputeJacobian(SNES, Vec, Mat, Mat);
905 PETSC_EXTERN PetscErrorCode SNESTestJacobian(SNES);
906 PETSC_EXTERN PetscErrorCode SNESTestFunction(SNES);
907 
908 PETSC_EXTERN PetscErrorCode SNESSetDM(SNES, DM);
909 PETSC_EXTERN PetscErrorCode SNESGetDM(SNES, DM *);
910 PETSC_EXTERN PetscErrorCode SNESSetNPC(SNES, SNES);
911 PETSC_EXTERN PetscErrorCode SNESGetNPC(SNES, SNES *);
912 PETSC_EXTERN PetscErrorCode SNESHasNPC(SNES, PetscBool *);
913 PETSC_EXTERN PetscErrorCode SNESApplyNPC(SNES, Vec, Vec, Vec);
914 PETSC_EXTERN PetscErrorCode SNESGetNPCFunction(SNES, Vec, PetscReal *);
915 PETSC_EXTERN PetscErrorCode SNESComputeFunctionDefaultNPC(SNES, Vec, Vec);
916 PETSC_EXTERN PetscErrorCode SNESSetNPCSide(SNES, PCSide);
917 PETSC_EXTERN PetscErrorCode SNESGetNPCSide(SNES, PCSide *);
918 PETSC_EXTERN PetscErrorCode SNESSetLineSearch(SNES, SNESLineSearch);
919 PETSC_EXTERN PetscErrorCode SNESGetLineSearch(SNES, SNESLineSearch *);
920 
921 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESGetLineSearch()", ) static inline PetscErrorCode SNESGetSNESLineSearch(SNES snes, SNESLineSearch *ls)
922 {
923   return SNESGetLineSearch(snes, ls);
924 }
925 PETSC_DEPRECATED_FUNCTION(3, 4, 0, "SNESSetLineSearch()", ) static inline PetscErrorCode SNESSetSNESLineSearch(SNES snes, SNESLineSearch ls)
926 {
927   return SNESSetLineSearch(snes, ls);
928 }
929 
930 PETSC_EXTERN PetscErrorCode SNESSetUpMatrices(SNES);
931 PETSC_EXTERN PetscErrorCode DMSNESSetFunction(DM, SNESFunctionFn *, void *);
932 PETSC_EXTERN PetscErrorCode DMSNESGetFunction(DM, SNESFunctionFn **, void **);
933 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionContextDestroy(DM, PetscErrorCode (*)(void *));
934 PETSC_EXTERN PetscErrorCode DMSNESSetMFFunction(DM, SNESFunctionFn *, void *);
935 PETSC_EXTERN PetscErrorCode DMSNESSetNGS(DM, SNESNGSFn *, void *);
936 PETSC_EXTERN PetscErrorCode DMSNESGetNGS(DM, SNESNGSFn **, void **);
937 PETSC_EXTERN PetscErrorCode DMSNESSetJacobian(DM, SNESJacobianFn *, void *);
938 PETSC_EXTERN PetscErrorCode DMSNESGetJacobian(DM, SNESJacobianFn **, void **);
939 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianContextDestroy(DM, PetscErrorCode (*)(void *));
940 PETSC_EXTERN PetscErrorCode DMSNESSetPicard(DM, SNESFunctionFn *, SNESJacobianFn *, void *);
941 PETSC_EXTERN PetscErrorCode DMSNESGetPicard(DM, SNESFunctionFn **, SNESJacobianFn **, void **);
942 PETSC_EXTERN PetscErrorCode DMSNESSetObjective(DM, SNESObjectiveFn *, void *);
943 PETSC_EXTERN PetscErrorCode DMSNESGetObjective(DM, SNESObjectiveFn **, void **);
944 PETSC_EXTERN PetscErrorCode DMCopyDMSNES(DM, DM);
945 
946 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionFn)(DMDALocalInfo *, void *, void *, void *);
947 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianFn)(DMDALocalInfo *, void *, Mat, Mat, void *);
948 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveFn)(DMDALocalInfo *, void *, PetscReal *, void *);
949 
950 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESFunctionVecFn)(DMDALocalInfo *, Vec, Vec, void *);
951 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESJacobianVecFn)(DMDALocalInfo *, Vec, Mat, Mat, void *);
952 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DMDASNESObjectiveVecFn)(DMDALocalInfo *, Vec, PetscReal *, void *);
953 
954 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocal(DM, InsertMode, DMDASNESFunctionFn *, void *);
955 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocal(DM, DMDASNESJacobianFn *, void *);
956 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocal(DM, DMDASNESObjectiveFn *, void *);
957 PETSC_EXTERN PetscErrorCode DMDASNESSetPicardLocal(DM, InsertMode, DMDASNESFunctionFn *, DMDASNESJacobianFn, void *);
958 
959 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocalVec(DM, InsertMode, DMDASNESFunctionVecFn *, void *);
960 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocalVec(DM, DMDASNESJacobianVecFn *, void *);
961 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocalVec(DM, DMDASNESObjectiveVecFn *, void *);
962 
963 PETSC_EXTERN PetscErrorCode DMSNESSetBoundaryLocal(DM, PetscErrorCode (*)(DM, Vec, void *), void *);
964 PETSC_EXTERN PetscErrorCode DMSNESSetObjectiveLocal(DM, PetscErrorCode (*)(DM, Vec, PetscReal *, void *), void *);
965 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionLocal(DM, PetscErrorCode (*)(DM, Vec, Vec, void *), void *);
966 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianLocal(DM, PetscErrorCode (*)(DM, Vec, Mat, Mat, void *), void *);
967 PETSC_EXTERN PetscErrorCode DMSNESGetBoundaryLocal(DM, PetscErrorCode (**)(DM, Vec, void *), void **);
968 PETSC_EXTERN PetscErrorCode DMSNESGetObjectiveLocal(DM, PetscErrorCode (**)(DM, Vec, PetscReal *, void *), void **);
969 PETSC_EXTERN PetscErrorCode DMSNESGetFunctionLocal(DM, PetscErrorCode (**)(DM, Vec, Vec, void *), void **);
970 PETSC_EXTERN PetscErrorCode DMSNESGetJacobianLocal(DM, PetscErrorCode (**)(DM, Vec, Mat, Mat, void *), void **);
971 
972 /* Routines for Multiblock solver */
973 PETSC_EXTERN PetscErrorCode SNESMultiblockSetFields(SNES, const char[], PetscInt, const PetscInt *);
974 PETSC_EXTERN PetscErrorCode SNESMultiblockSetIS(SNES, const char[], IS);
975 PETSC_EXTERN PetscErrorCode SNESMultiblockSetBlockSize(SNES, PetscInt);
976 PETSC_EXTERN PetscErrorCode SNESMultiblockSetType(SNES, PCCompositeType);
977 PETSC_EXTERN PetscErrorCode SNESMultiblockGetSubSNES(SNES, PetscInt *, SNES *[]);
978 
979 /*J
980    SNESMSType - String with the name of a PETSc `SNESMS` method.
981 
982    Level: intermediate
983 
984 .seealso: [](ch_snes), `SNESMS`, `SNESMSGetType()`, `SNESMSSetType()`, `SNES`
985 J*/
986 typedef const char *SNESMSType;
987 #define SNESMSM62       "m62"
988 #define SNESMSEULER     "euler"
989 #define SNESMSJAMESON83 "jameson83"
990 #define SNESMSVLTP11    "vltp11"
991 #define SNESMSVLTP21    "vltp21"
992 #define SNESMSVLTP31    "vltp31"
993 #define SNESMSVLTP41    "vltp41"
994 #define SNESMSVLTP51    "vltp51"
995 #define SNESMSVLTP61    "vltp61"
996 
997 PETSC_EXTERN PetscErrorCode SNESMSRegister(SNESMSType, PetscInt, PetscInt, PetscReal, const PetscReal[], const PetscReal[], const PetscReal[]);
998 PETSC_EXTERN PetscErrorCode SNESMSRegisterAll(void);
999 PETSC_EXTERN PetscErrorCode SNESMSGetType(SNES, SNESMSType *);
1000 PETSC_EXTERN PetscErrorCode SNESMSSetType(SNES, SNESMSType);
1001 PETSC_EXTERN PetscErrorCode SNESMSGetDamping(SNES, PetscReal *);
1002 PETSC_EXTERN PetscErrorCode SNESMSSetDamping(SNES, PetscReal);
1003 PETSC_EXTERN PetscErrorCode SNESMSFinalizePackage(void);
1004 PETSC_EXTERN PetscErrorCode SNESMSInitializePackage(void);
1005 PETSC_EXTERN PetscErrorCode SNESMSRegisterDestroy(void);
1006 
1007 /*MC
1008    SNESNGMRESRestartType - the restart approach used by `SNESNGMRES`
1009 
1010   Values:
1011 +   `SNES_NGMRES_RESTART_NONE`       - never restart
1012 .   `SNES_NGMRES_RESTART_DIFFERENCE` - restart based upon difference criteria
1013 -   `SNES_NGMRES_RESTART_PERIODIC`   - restart after a fixed number of iterations
1014 
1015   Options Database Keys:
1016 + -snes_ngmres_restart_type <difference,periodic,none> - set the restart type
1017 - -snes_ngmres_restart <30>                            - sets the number of iterations before restart for periodic
1018 
1019    Level: intermediate
1020 
1021 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1022           `SNESNGMRESGetRestartType()`, `SNESNGMRESSelectType`
1023 M*/
1024 typedef enum {
1025   SNES_NGMRES_RESTART_NONE       = 0,
1026   SNES_NGMRES_RESTART_PERIODIC   = 1,
1027   SNES_NGMRES_RESTART_DIFFERENCE = 2
1028 } SNESNGMRESRestartType;
1029 PETSC_EXTERN const char *const SNESNGMRESRestartTypes[];
1030 
1031 /*MC
1032    SNESNGMRESSelectType - the approach used by `SNESNGMRES` to determine how the candidate solution and
1033   combined solution are used to create the next iterate.
1034 
1035    Values:
1036 +   `SNES_NGMRES_SELECT_NONE`       - choose the combined solution all the time
1037 .   `SNES_NGMRES_SELECT_DIFFERENCE` - choose based upon the selection criteria
1038 -   `SNES_NGMRES_SELECT_LINESEARCH` - choose based upon line search combination
1039 
1040   Options Database Key:
1041 . -snes_ngmres_select_type<difference,none,linesearch> - select type
1042 
1043    Level: intermediate
1044 
1045 .seealso: `SNES, `SNESNGMRES`, `SNESNGMRESSetSelectType()`, `SNESNGMRESGetSelectType()`, `SNESNGMRESSetRestartType()`,
1046           `SNESNGMRESGetRestartType()`, `SNESNGMRESRestartType`
1047 M*/
1048 typedef enum {
1049   SNES_NGMRES_SELECT_NONE       = 0,
1050   SNES_NGMRES_SELECT_DIFFERENCE = 1,
1051   SNES_NGMRES_SELECT_LINESEARCH = 2
1052 } SNESNGMRESSelectType;
1053 PETSC_EXTERN const char *const SNESNGMRESSelectTypes[];
1054 
1055 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartType(SNES, SNESNGMRESRestartType);
1056 PETSC_EXTERN PetscErrorCode SNESNGMRESSetSelectType(SNES, SNESNGMRESSelectType);
1057 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartFmRise(SNES, PetscBool);
1058 PETSC_EXTERN PetscErrorCode SNESNGMRESGetRestartFmRise(SNES, PetscBool *);
1059 
1060 /*MC
1061    SNESNCGType - the conjugate update approach for `SNESNCG`
1062 
1063    Values:
1064 +   `SNES_NCG_FR`  - Fletcher-Reeves update
1065 .   `SNES_NCG_PRP` - Polak-Ribiere-Polyak update, the default and the only one that tolerates generalized search directions
1066 .   `SNES_NCG_HS`  - Hestenes-Steifel update
1067 .   `SNES_NCG_DY`  - Dai-Yuan update
1068 -   `SNES_NCG_CD`  - Conjugate Descent update
1069 
1070   Options Database Key:
1071 . -snes_ncg_type<fr,prp,hs,dy,cd> - select type
1072 
1073    Level: intermediate
1074 
1075 .seealso: `SNES, `SNESNCG`, `SNESNCGSetType()`
1076 M*/
1077 typedef enum {
1078   SNES_NCG_FR  = 0,
1079   SNES_NCG_PRP = 1,
1080   SNES_NCG_HS  = 2,
1081   SNES_NCG_DY  = 3,
1082   SNES_NCG_CD  = 4
1083 } SNESNCGType;
1084 PETSC_EXTERN const char *const SNESNCGTypes[];
1085 
1086 PETSC_EXTERN PetscErrorCode SNESNCGSetType(SNES, SNESNCGType);
1087 
1088 /*MC
1089    SNESQNScaleType - the scaling type used by `SNESQN`
1090 
1091    Values:
1092 +   `SNES_QN_SCALE_NONE`     - don't scale the problem
1093 .   `SNES_QN_SCALE_SCALAR`   - use Shanno scaling
1094 .   `SNES_QN_SCALE_DIAGONAL` - scale with a diagonalized BFGS formula (see Gilbert and Lemarechal 1989), available
1095 -   `SNES_QN_SCALE_JACOBIAN` - scale by solving a linear system coming from the Jacobian you provided with `SNESSetJacobian()`
1096                                computed at the first iteration of `SNESQN` and at ever restart.
1097 
1098     Options Database Key:
1099 . -snes_qn_scale_type <diagonal,none,scalar,jacobian> - Scaling type
1100 
1101    Level: intermediate
1102 
1103 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNRestartType`
1104 M*/
1105 typedef enum {
1106   SNES_QN_SCALE_DEFAULT  = 0,
1107   SNES_QN_SCALE_NONE     = 1,
1108   SNES_QN_SCALE_SCALAR   = 2,
1109   SNES_QN_SCALE_DIAGONAL = 3,
1110   SNES_QN_SCALE_JACOBIAN = 4
1111 } SNESQNScaleType;
1112 PETSC_EXTERN const char *const SNESQNScaleTypes[];
1113 
1114 /*MC
1115    SNESQNRestartType - the restart approached used by `SNESQN`
1116 
1117    Values:
1118 +   `SNES_QN_RESTART_NONE`     - never restart
1119 .   `SNES_QN_RESTART_POWELL`   - restart based upon descent criteria
1120 -   `SNES_QN_RESTART_PERIODIC` - restart after a fixed number of iterations
1121 
1122   Options Database Keys:
1123 + -snes_qn_restart_type <powell,periodic,none> - set the restart type
1124 - -snes_qn_m <m>                               - sets the number of stored updates and the restart period for periodic
1125 
1126    Level: intermediate
1127 
1128 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNType`, `SNESQNSetType()`, `SNESQNSetRestartType()`, `SNESQNScaleType`
1129 M*/
1130 typedef enum {
1131   SNES_QN_RESTART_DEFAULT  = 0,
1132   SNES_QN_RESTART_NONE     = 1,
1133   SNES_QN_RESTART_POWELL   = 2,
1134   SNES_QN_RESTART_PERIODIC = 3
1135 } SNESQNRestartType;
1136 PETSC_EXTERN const char *const SNESQNRestartTypes[];
1137 
1138 /*MC
1139    SNESQNType - the type used by `SNESQN`
1140 
1141   Values:
1142 +   `SNES_QN_LBFGS`      - LBFGS variant
1143 .   `SNES_QN_BROYDEN`    - Broyden variant
1144 -   `SNES_QN_BADBROYDEN` - Bad Broyden variant
1145 
1146   Options Database Key:
1147 . -snes_qn_type <lbfgs,broyden,badbroyden> - quasi-Newton type
1148 
1149    Level: intermediate
1150 
1151 .seealso: `SNES, `SNESQN`, `SNESQNSetScaleType()`, `SNESQNSetType()`, `SNESQNScaleType`, `SNESQNRestartType`, `SNESQNSetRestartType()`
1152 M*/
1153 typedef enum {
1154   SNES_QN_LBFGS      = 0,
1155   SNES_QN_BROYDEN    = 1,
1156   SNES_QN_BADBROYDEN = 2
1157 } SNESQNType;
1158 PETSC_EXTERN const char *const SNESQNTypes[];
1159 
1160 PETSC_EXTERN PetscErrorCode SNESQNSetType(SNES, SNESQNType);
1161 PETSC_EXTERN PetscErrorCode SNESQNSetScaleType(SNES, SNESQNScaleType);
1162 PETSC_EXTERN PetscErrorCode SNESQNSetRestartType(SNES, SNESQNRestartType);
1163 
1164 PETSC_EXTERN PetscErrorCode SNESNASMGetType(SNES, PCASMType *);
1165 PETSC_EXTERN PetscErrorCode SNESNASMSetType(SNES, PCASMType);
1166 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomains(SNES, PetscInt *, SNES **, VecScatter **, VecScatter **, VecScatter **);
1167 PETSC_EXTERN PetscErrorCode SNESNASMSetSubdomains(SNES, PetscInt, SNES *, VecScatter *, VecScatter *, VecScatter *);
1168 PETSC_EXTERN PetscErrorCode SNESNASMSetDamping(SNES, PetscReal);
1169 PETSC_EXTERN PetscErrorCode SNESNASMGetDamping(SNES, PetscReal *);
1170 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomainVecs(SNES, PetscInt *, Vec **, Vec **, Vec **, Vec **);
1171 PETSC_EXTERN PetscErrorCode SNESNASMSetComputeFinalJacobian(SNES, PetscBool);
1172 PETSC_EXTERN PetscErrorCode SNESNASMGetSNES(SNES, PetscInt, SNES *);
1173 PETSC_EXTERN PetscErrorCode SNESNASMGetNumber(SNES, PetscInt *);
1174 PETSC_EXTERN PetscErrorCode SNESNASMSetWeight(SNES, Vec);
1175 
1176 /*E
1177   SNESCompositeType - Determines how two or more preconditioners are composed with the `SNESType` of `SNESCOMPOSITE`
1178 
1179   Values:
1180 + `SNES_COMPOSITE_ADDITIVE`        - results from application of all preconditioners are added together
1181 . `SNES_COMPOSITE_MULTIPLICATIVE`  - preconditioners are applied sequentially to the residual freshly
1182                                      computed after the previous preconditioner application
1183 - `SNES_COMPOSITE_ADDITIVEOPTIMAL` - uses a linear combination of the solutions obtained with each preconditioner that approximately minimize the function
1184                                      value at the new iteration.
1185 
1186    Level: beginner
1187 
1188 .seealso: [](sec_pc), `PCCOMPOSITE`, `PCFIELDSPLIT`, `PC`, `PCCompositeSetType()`, `PCCompositeType`
1189 E*/
1190 typedef enum {
1191   SNES_COMPOSITE_ADDITIVE,
1192   SNES_COMPOSITE_MULTIPLICATIVE,
1193   SNES_COMPOSITE_ADDITIVEOPTIMAL
1194 } SNESCompositeType;
1195 PETSC_EXTERN const char *const SNESCompositeTypes[];
1196 
1197 PETSC_EXTERN PetscErrorCode SNESCompositeSetType(SNES, SNESCompositeType);
1198 PETSC_EXTERN PetscErrorCode SNESCompositeAddSNES(SNES, SNESType);
1199 PETSC_EXTERN PetscErrorCode SNESCompositeGetSNES(SNES, PetscInt, SNES *);
1200 PETSC_EXTERN PetscErrorCode SNESCompositeGetNumber(SNES, PetscInt *);
1201 PETSC_EXTERN PetscErrorCode SNESCompositeSetDamping(SNES, PetscInt, PetscReal);
1202 
1203 PETSC_EXTERN PetscErrorCode SNESPatchSetDiscretisationInfo(SNES, PetscInt, DM *, PetscInt *, PetscInt *, const PetscInt **, const PetscInt *, PetscInt, const PetscInt *, PetscInt, const PetscInt *);
1204 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeOperator(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Mat, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1205 PETSC_EXTERN PetscErrorCode SNESPatchSetComputeFunction(SNES, PetscErrorCode (*func)(PC, PetscInt, Vec, Vec, IS, PetscInt, const PetscInt *, const PetscInt *, void *), void *);
1206 PETSC_EXTERN PetscErrorCode SNESPatchSetConstructType(SNES, PCPatchConstructType, PetscErrorCode (*func)(PC, PetscInt *, IS **, IS *, void *), void *);
1207 PETSC_EXTERN PetscErrorCode SNESPatchSetCellNumbering(SNES, PetscSection);
1208 
1209 /*E
1210     SNESFASType - Determines the type of nonlinear multigrid method that is run.
1211 
1212    Values:
1213 +  `SNES_FAS_MULTIPLICATIVE` (default) - traditional V or W cycle as determined by `SNESFASSetCycles()`
1214 .  `SNES_FAS_ADDITIVE`                 - additive FAS cycle
1215 .  `SNES_FAS_FULL`                     - full FAS cycle
1216 -  `SNES_FAS_KASKADE`                  - Kaskade FAS cycle
1217 
1218    Level: beginner
1219 
1220 .seealso: [](ch_snes), `SNESFAS`, `PCMGSetType()`, `PCMGType`
1221 E*/
1222 typedef enum {
1223   SNES_FAS_MULTIPLICATIVE,
1224   SNES_FAS_ADDITIVE,
1225   SNES_FAS_FULL,
1226   SNES_FAS_KASKADE
1227 } SNESFASType;
1228 PETSC_EXTERN const char *const SNESFASTypes[];
1229 
1230 /* called on the finest level FAS instance*/
1231 PETSC_EXTERN PetscErrorCode SNESFASSetType(SNES, SNESFASType);
1232 PETSC_EXTERN PetscErrorCode SNESFASGetType(SNES, SNESFASType *);
1233 PETSC_EXTERN PetscErrorCode SNESFASSetLevels(SNES, PetscInt, MPI_Comm *);
1234 PETSC_EXTERN PetscErrorCode SNESFASGetLevels(SNES, PetscInt *);
1235 PETSC_EXTERN PetscErrorCode SNESFASGetCycleSNES(SNES, PetscInt, SNES *);
1236 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothUp(SNES, PetscInt);
1237 PETSC_EXTERN PetscErrorCode SNESFASSetNumberSmoothDown(SNES, PetscInt);
1238 PETSC_EXTERN PetscErrorCode SNESFASSetCycles(SNES, PetscInt);
1239 PETSC_EXTERN PetscErrorCode SNESFASSetMonitor(SNES, PetscViewerAndFormat *, PetscBool);
1240 PETSC_EXTERN PetscErrorCode SNESFASSetLog(SNES, PetscBool);
1241 
1242 PETSC_EXTERN PetscErrorCode SNESFASSetGalerkin(SNES, PetscBool);
1243 PETSC_EXTERN PetscErrorCode SNESFASGetGalerkin(SNES, PetscBool *);
1244 PETSC_EXTERN PetscErrorCode SNESFASGalerkinFunctionDefault(SNES, Vec, Vec, void *);
1245 
1246 /* called on any level -- "Cycle" FAS instance */
1247 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmoother(SNES, SNES *);
1248 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherUp(SNES, SNES *);
1249 PETSC_EXTERN PetscErrorCode SNESFASCycleGetSmootherDown(SNES, SNES *);
1250 PETSC_EXTERN PetscErrorCode SNESFASCycleGetCorrection(SNES, SNES *);
1251 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInterpolation(SNES, Mat *);
1252 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRestriction(SNES, Mat *);
1253 PETSC_EXTERN PetscErrorCode SNESFASCycleGetInjection(SNES, Mat *);
1254 PETSC_EXTERN PetscErrorCode SNESFASCycleGetRScale(SNES, Vec *);
1255 PETSC_EXTERN PetscErrorCode SNESFASCycleSetCycles(SNES, PetscInt);
1256 PETSC_EXTERN PetscErrorCode SNESFASCycleIsFine(SNES, PetscBool *);
1257 
1258 /* called on the (outer) finest level FAS to set/get parameters on any level instance */
1259 PETSC_EXTERN PetscErrorCode SNESFASSetInterpolation(SNES, PetscInt, Mat);
1260 PETSC_EXTERN PetscErrorCode SNESFASGetInterpolation(SNES, PetscInt, Mat *);
1261 PETSC_EXTERN PetscErrorCode SNESFASSetRestriction(SNES, PetscInt, Mat);
1262 PETSC_EXTERN PetscErrorCode SNESFASGetRestriction(SNES, PetscInt, Mat *);
1263 PETSC_EXTERN PetscErrorCode SNESFASSetInjection(SNES, PetscInt, Mat);
1264 PETSC_EXTERN PetscErrorCode SNESFASGetInjection(SNES, PetscInt, Mat *);
1265 PETSC_EXTERN PetscErrorCode SNESFASSetRScale(SNES, PetscInt, Vec);
1266 PETSC_EXTERN PetscErrorCode SNESFASGetRScale(SNES, PetscInt, Vec *);
1267 PETSC_EXTERN PetscErrorCode SNESFASSetContinuation(SNES, PetscBool);
1268 
1269 PETSC_EXTERN PetscErrorCode SNESFASGetSmoother(SNES, PetscInt, SNES *);
1270 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherUp(SNES, PetscInt, SNES *);
1271 PETSC_EXTERN PetscErrorCode SNESFASGetSmootherDown(SNES, PetscInt, SNES *);
1272 PETSC_EXTERN PetscErrorCode SNESFASGetCoarseSolve(SNES, SNES *);
1273 
1274 /* parameters for full FAS */
1275 PETSC_EXTERN PetscErrorCode SNESFASFullSetDownSweep(SNES, PetscBool);
1276 PETSC_EXTERN PetscErrorCode SNESFASCreateCoarseVec(SNES, Vec *);
1277 PETSC_EXTERN PetscErrorCode SNESFASRestrict(SNES, Vec, Vec);
1278 PETSC_EXTERN PetscErrorCode SNESFASFullSetTotal(SNES, PetscBool);
1279 PETSC_EXTERN PetscErrorCode SNESFASFullGetTotal(SNES, PetscBool *);
1280 
1281 PETSC_EXTERN PetscErrorCode DMSNESCheckDiscretization(SNES, DM, PetscReal, Vec, PetscReal, PetscReal[]);
1282 PETSC_EXTERN PetscErrorCode DMSNESCheckResidual(SNES, DM, Vec, PetscReal, PetscReal *);
1283 PETSC_EXTERN PetscErrorCode DMSNESCheckJacobian(SNES, DM, Vec, PetscReal, PetscBool *, PetscReal *);
1284 PETSC_EXTERN PetscErrorCode DMSNESCheckFromOptions(SNES, Vec);
1285 PETSC_EXTERN PetscErrorCode DMSNESComputeJacobianAction(DM, Vec, Vec, Vec, void *);
1286 PETSC_EXTERN PetscErrorCode DMSNESCreateJacobianMF(DM, Vec, void *, Mat *);
1287