xref: /petsc/include/petscsnes.h (revision 90a8ba9be28a04c4922db9ec087f82b84f0205dc) 
1 /*
2     User interface for the nonlinear solvers package.
3 */
4 #if !defined(__PETSCSNES_H)
5 #define __PETSCSNES_H
6 #include <petscksp.h>
7 #include <petscdmtypes.h>
8 #include <petscdmdatypes.h>
9 
10 /*S
11      SNES - Abstract PETSc object that manages all nonlinear solves
12 
13    Level: beginner
14 
15   Concepts: nonlinear solvers
16 
17 .seealso:  SNESCreate(), SNESSetType(), SNESType, TS, KSP, KSP, PC
18 S*/
19 typedef struct _p_SNES* SNES;
20 
21 /*J
22     SNESType - String with the name of a PETSc SNES method or the creation function
23        with an optional dynamic library name, for example
24        http://www.mcs.anl.gov/petsc/lib.a:mysnescreate()
25 
26    Level: beginner
27 
28 .seealso: SNESSetType(), SNES
29 J*/
30 typedef const char* SNESType;
31 #define SNESNEWTONLS     "newtonls"
32 #define SNESNEWTONTR     "newtontr"
33 #define SNESPYTHON       "python"
34 #define SNESTEST         "test"
35 #define SNESNRICHARDSON  "nrichardson"
36 #define SNESKSPONLY      "ksponly"
37 #define SNESVINEWTONRSLS "vinewtonrsls"
38 #define SNESVINEWTONSSLS "vinewtonssls"
39 #define SNESNGMRES       "ngmres"
40 #define SNESQN           "qn"
41 #define SNESSHELL        "shell"
42 #define SNESGS           "gs"
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 
51 /* Logging support */
52 PETSC_EXTERN PetscClassId SNES_CLASSID;
53 PETSC_EXTERN PetscClassId DMSNES_CLASSID;
54 
55 PETSC_EXTERN PetscErrorCode SNESInitializePackage(void);
56 
57 PETSC_EXTERN PetscErrorCode SNESCreate(MPI_Comm,SNES*);
58 PETSC_EXTERN PetscErrorCode SNESReset(SNES);
59 PETSC_EXTERN PetscErrorCode SNESDestroy(SNES*);
60 PETSC_EXTERN PetscErrorCode SNESSetType(SNES,SNESType);
61 PETSC_EXTERN PetscErrorCode SNESMonitor(SNES,PetscInt,PetscReal);
62 PETSC_EXTERN PetscErrorCode SNESMonitorSet(SNES,PetscErrorCode(*)(SNES,PetscInt,PetscReal,void*),void *,PetscErrorCode (*)(void**));
63 PETSC_EXTERN PetscErrorCode SNESMonitorCancel(SNES);
64 PETSC_EXTERN PetscErrorCode SNESSetConvergenceHistory(SNES,PetscReal[],PetscInt[],PetscInt,PetscBool );
65 PETSC_EXTERN PetscErrorCode SNESGetConvergenceHistory(SNES,PetscReal*[],PetscInt *[],PetscInt *);
66 PETSC_EXTERN PetscErrorCode SNESSetUp(SNES);
67 PETSC_EXTERN PetscErrorCode SNESSolve(SNES,Vec,Vec);
68 PETSC_EXTERN PetscErrorCode SNESSetErrorIfNotConverged(SNES,PetscBool );
69 PETSC_EXTERN PetscErrorCode SNESGetErrorIfNotConverged(SNES,PetscBool  *);
70 
71 PETSC_EXTERN PetscErrorCode SNESSetWorkVecs(SNES,PetscInt);
72 
73 PETSC_EXTERN PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*)(SNES));
74 
75 PETSC_EXTERN PetscErrorCode SNESSetUpdate(SNES, PetscErrorCode (*)(SNES, PetscInt));
76 
77 PETSC_EXTERN PetscErrorCode SNESRegisterAll(void);
78 
79 PETSC_EXTERN PetscErrorCode SNESRegister(const char[],PetscErrorCode (*)(SNES));
80 
81 PETSC_EXTERN PetscErrorCode SNESGetKSP(SNES,KSP*);
82 PETSC_EXTERN PetscErrorCode SNESSetKSP(SNES,KSP);
83 PETSC_EXTERN PetscErrorCode SNESGetSolution(SNES,Vec*);
84 PETSC_EXTERN PetscErrorCode SNESGetSolutionUpdate(SNES,Vec*);
85 PETSC_EXTERN PetscErrorCode SNESGetRhs(SNES,Vec*);
86 PETSC_EXTERN PetscErrorCode SNESView(SNES,PetscViewer);
87 PETSC_EXTERN PetscErrorCode SNESLoad(SNES,PetscViewer);
88 
89 #define SNES_FILE_CLASSID 1211224
90 
91 PETSC_EXTERN PetscErrorCode SNESSetOptionsPrefix(SNES,const char[]);
92 PETSC_EXTERN PetscErrorCode SNESAppendOptionsPrefix(SNES,const char[]);
93 PETSC_EXTERN PetscErrorCode SNESGetOptionsPrefix(SNES,const char*[]);
94 PETSC_EXTERN PetscErrorCode SNESSetFromOptions(SNES);
95 
96 PETSC_EXTERN PetscErrorCode MatCreateSNESMF(SNES,Mat*);
97 PETSC_EXTERN PetscErrorCode MatMFFDComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
98 
99 PETSC_EXTERN PetscErrorCode MatDAADSetSNES(Mat,SNES);
100 
101 PETSC_EXTERN PetscErrorCode SNESGetType(SNES,SNESType*);
102 PETSC_EXTERN PetscErrorCode SNESMonitorDefault(SNES,PetscInt,PetscReal,void *);
103 PETSC_EXTERN PetscErrorCode SNESMonitorRange(SNES,PetscInt,PetscReal,void *);
104 PETSC_EXTERN PetscErrorCode SNESMonitorRatio(SNES,PetscInt,PetscReal,void *);
105 PETSC_EXTERN PetscErrorCode SNESMonitorSetRatio(SNES,PetscViewer);
106 PETSC_EXTERN PetscErrorCode SNESMonitorSolution(SNES,PetscInt,PetscReal,void *);
107 PETSC_EXTERN PetscErrorCode SNESMonitorResidual(SNES,PetscInt,PetscReal,void *);
108 PETSC_EXTERN PetscErrorCode SNESMonitorSolutionUpdate(SNES,PetscInt,PetscReal,void *);
109 PETSC_EXTERN PetscErrorCode SNESMonitorDefaultShort(SNES,PetscInt,PetscReal,void *);
110 PETSC_EXTERN PetscErrorCode SNESMonitorJacUpdateSpectrum(SNES,PetscInt,PetscReal,void *);
111 PETSC_EXTERN PetscErrorCode SNESSetTolerances(SNES,PetscReal,PetscReal,PetscReal,PetscInt,PetscInt);
112 PETSC_EXTERN PetscErrorCode SNESGetTolerances(SNES,PetscReal*,PetscReal*,PetscReal*,PetscInt*,PetscInt*);
113 PETSC_EXTERN PetscErrorCode SNESSetTrustRegionTolerance(SNES,PetscReal);
114 PETSC_EXTERN PetscErrorCode SNESGetFunctionNorm(SNES,PetscReal*);
115 PETSC_EXTERN PetscErrorCode SNESSetFunctionNorm(SNES,PetscReal);
116 PETSC_EXTERN PetscErrorCode SNESGetIterationNumber(SNES,PetscInt*);
117 PETSC_EXTERN PetscErrorCode SNESSetIterationNumber(SNES,PetscInt);
118 
119 PETSC_EXTERN PetscErrorCode SNESGetNonlinearStepFailures(SNES,PetscInt*);
120 PETSC_EXTERN PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES,PetscInt);
121 PETSC_EXTERN PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES,PetscInt*);
122 PETSC_EXTERN PetscErrorCode SNESGetNumberFunctionEvals(SNES,PetscInt*);
123 
124 PETSC_EXTERN PetscErrorCode SNESSetLagPreconditioner(SNES,PetscInt);
125 PETSC_EXTERN PetscErrorCode SNESGetLagPreconditioner(SNES,PetscInt*);
126 PETSC_EXTERN PetscErrorCode SNESSetLagJacobian(SNES,PetscInt);
127 PETSC_EXTERN PetscErrorCode SNESGetLagJacobian(SNES,PetscInt*);
128 PETSC_EXTERN PetscErrorCode SNESSetGridSequence(SNES,PetscInt);
129 
130 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveIterations(SNES,PetscInt*);
131 PETSC_EXTERN PetscErrorCode SNESGetLinearSolveFailures(SNES,PetscInt*);
132 PETSC_EXTERN PetscErrorCode SNESSetMaxLinearSolveFailures(SNES,PetscInt);
133 PETSC_EXTERN PetscErrorCode SNESGetMaxLinearSolveFailures(SNES,PetscInt*);
134 
135 PETSC_EXTERN PetscErrorCode SNESKSPSetUseEW(SNES,PetscBool );
136 PETSC_EXTERN PetscErrorCode SNESKSPGetUseEW(SNES,PetscBool *);
137 PETSC_EXTERN PetscErrorCode SNESKSPSetParametersEW(SNES,PetscInt,PetscReal,PetscReal,PetscReal,PetscReal,PetscReal,PetscReal);
138 PETSC_EXTERN PetscErrorCode SNESKSPGetParametersEW(SNES,PetscInt*,PetscReal*,PetscReal*,PetscReal*,PetscReal*,PetscReal*,PetscReal*);
139 
140 #include <petscdrawtypes.h>
141 PETSC_EXTERN PetscErrorCode SNESMonitorLGCreate(const char[],const char[],int,int,int,int,PetscDrawLG*);
142 PETSC_EXTERN PetscErrorCode SNESMonitorLGResidualNorm(SNES,PetscInt,PetscReal,void*);
143 PETSC_EXTERN PetscErrorCode SNESMonitorLGDestroy(PetscDrawLG*);
144 PETSC_EXTERN PetscErrorCode SNESMonitorLGRange(SNES,PetscInt,PetscReal,void*);
145 
146 PETSC_EXTERN PetscErrorCode SNESSetApplicationContext(SNES,void *);
147 PETSC_EXTERN PetscErrorCode SNESGetApplicationContext(SNES,void *);
148 PETSC_EXTERN PetscErrorCode SNESSetComputeApplicationContext(SNES,PetscErrorCode (*)(SNES,void**),PetscErrorCode (*)(void**));
149 
150 PETSC_EXTERN PetscErrorCode SNESPythonSetType(SNES,const char[]);
151 
152 PETSC_EXTERN PetscErrorCode SNESSetFunctionDomainError(SNES);
153 PETSC_EXTERN PetscErrorCode SNESGetFunctionDomainError(SNES, PetscBool *);
154 
155 /*E
156     SNESConvergedReason - reason a SNES method was said to
157          have converged or diverged
158 
159    Level: beginner
160 
161    The two most common reasons for divergence are
162 $   1) an incorrectly coded or computed Jacobian or
163 $   2) failure or lack of convergence in the linear system (in this case we recommend
164 $      testing with -pc_type lu to eliminate the linear solver as the cause of the problem).
165 
166    Diverged Reasons:
167 .    SNES_DIVERGED_LOCAL_MIN - this can only occur when using the line-search variant of SNES.
168        The line search wants to minimize Q(alpha) = 1/2 || F(x + alpha s) ||^2_2  this occurs
169        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
170        you get Q'(alpha) = -F(x)^T F'(x)^(-1)^T F'(x+alpha s)F(x+alpha s); when alpha = 0
171        Q'(0) = - ||F(x)||^2_2 which is always NEGATIVE if F'(x) is invertible. This means the Newton
172        direction is a descent direction and the line search should succeed if alpha is small enough.
173 
174        If F'(x) is NOT invertible AND F'(x)^T F(x) = 0 then Q'(0) = 0 and the Newton direction
175        is NOT a descent direction so the line search will fail. All one can do at this point
176        is change the initial guess and try again.
177 
178        An alternative explanation: Newton's method can be regarded as replacing the function with
179        its linear approximation and minimizing the 2-norm of that. That is F(x+s) approx F(x) + F'(x)s
180        so we minimize || F(x) + F'(x) s ||^2_2; do this using Least Squares. If F'(x) is invertible then
181        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
182        exists a nontrival (that is F'(x)s != 0) solution to the equation and this direction is
183        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)
184        = - (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
185        and F'(x)^T F'(x) has no negative eigenvalues Q'(0) < 0 so s is a descent direction and the line
186        search should succeed for small enough alpha.
187 
188        Note that this RARELY happens in practice. Far more likely the linear system is not being solved
189        (well enough?) or the Jacobian is wrong.
190 
191    SNES_DIVERGED_MAX_IT means that the solver reached the maximum number of iterations without satisfying any
192    convergence criteria. SNES_CONVERGED_ITS means that SNESSkipConverged() was chosen as the convergence test;
193    thus the usual convergence criteria have not been checked and may or may not be satisfied.
194 
195    Developer Notes: this must match finclude/petscsnes.h
196 
197        The string versions of these are in SNESConvergedReason, if you change any value here you must
198      also adjust that array.
199 
200    Each reason has its own manual page.
201 
202 .seealso: SNESSolve(), SNESGetConvergedReason(), KSPConvergedReason, SNESSetConvergenceTest()
203 E*/
204 typedef enum {/* converged */
205               SNES_CONVERGED_FNORM_ABS         =  2, /* ||F|| < atol */
206               SNES_CONVERGED_FNORM_RELATIVE    =  3, /* ||F|| < rtol*||F_initial|| */
207               SNES_CONVERGED_SNORM_RELATIVE    =  4, /* Newton computed step size small; || delta x || < stol || x ||*/
208               SNES_CONVERGED_ITS               =  5, /* maximum iterations reached */
209               SNES_CONVERGED_TR_DELTA          =  7,
210               /* diverged */
211               SNES_DIVERGED_FUNCTION_DOMAIN     = -1, /* the new x location passed the function is not in the domain of F */
212               SNES_DIVERGED_FUNCTION_COUNT      = -2,
213               SNES_DIVERGED_LINEAR_SOLVE        = -3, /* the linear solve failed */
214               SNES_DIVERGED_FNORM_NAN           = -4,
215               SNES_DIVERGED_MAX_IT              = -5,
216               SNES_DIVERGED_LINE_SEARCH         = -6, /* the line search failed */
217               SNES_DIVERGED_INNER               = -7, /* inner solve failed */
218               SNES_DIVERGED_LOCAL_MIN           = -8, /* || J^T b || is small, implies converged to local minimum of F() */
219               SNES_CONVERGED_ITERATING          =  0} SNESConvergedReason;
220 PETSC_EXTERN const char *const*SNESConvergedReasons;
221 
222 /*MC
223      SNES_CONVERGED_FNORM_ABS - 2-norm(F) <= abstol
224 
225    Level: beginner
226 
227 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
228 
229 M*/
230 
231 /*MC
232      SNES_CONVERGED_FNORM_RELATIVE - 2-norm(F) <= rtol*2-norm(F(x_0)) where x_0 is the initial guess
233 
234    Level: beginner
235 
236 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
237 
238 M*/
239 
240 /*MC
241      SNES_CONVERGED_SNORM_RELATIVE - The 2-norm of the last step <= stol * 2-norm(x) where x is the current
242           solution and stol is the 4th argument to SNESSetTolerances()
243 
244      Options Database Keys:
245       -snes_stol <stol> - the step tolerance
246 
247    Level: beginner
248 
249 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
250 
251 M*/
252 
253 /*MC
254      SNES_DIVERGED_FUNCTION_COUNT - The user provided function has been called more times then the final
255          argument to SNESSetTolerances()
256 
257    Level: beginner
258 
259 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
260 
261 M*/
262 
263 /*MC
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 
267    Level: beginner
268 
269 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
270 
271 M*/
272 
273 /*MC
274      SNES_DIVERGED_MAX_IT - SNESSolve() has reached the maximum number of iterations requested
275 
276    Level: beginner
277 
278 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
279 
280 M*/
281 
282 /*MC
283      SNES_DIVERGED_LINE_SEARCH - The line search has failed. This only occurs for a SNES solvers that use a line search
284 
285    Level: beginner
286 
287 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances(), SNESLineSearch
288 
289 M*/
290 
291 /*MC
292      SNES_DIVERGED_LOCAL_MIN - the algorithm seems to have stagnated at a local minimum that is not zero.
293         See the manual page for SNESConvergedReason for more details
294 
295    Level: beginner
296 
297 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
298 
299 M*/
300 
301 /*MC
302      SNES_CONERGED_ITERATING - this only occurs if SNESGetConvergedReason() is called during the SNESSolve()
303 
304    Level: beginner
305 
306 .seealso:  SNESSolve(), SNESGetConvergedReason(), SNESConvergedReason, SNESSetTolerances()
307 
308 M*/
309 
310 PETSC_EXTERN PetscErrorCode SNESSetConvergenceTest(SNES,PetscErrorCode (*)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void*,PetscErrorCode (*)(void*));
311 PETSC_EXTERN PetscErrorCode SNESConvergedDefault(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*);
312 PETSC_EXTERN PetscErrorCode SNESSkipConverged(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*);
313 PETSC_EXTERN PetscErrorCode SNESGetConvergedReason(SNES,SNESConvergedReason*);
314 
315 PETSC_EXTERN PetscErrorCode SNESDMMeshComputeFunction(SNES,Vec,Vec,void*);
316 PETSC_EXTERN PetscErrorCode SNESDMMeshComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
317 
318 /* --------- Solving systems of nonlinear equations --------------- */
319 PETSC_EXTERN PetscErrorCode SNESSetFunction(SNES,Vec,PetscErrorCode (*SNESFunction)(SNES,Vec,Vec,void*),void*);
320 PETSC_EXTERN PetscErrorCode SNESGetFunction(SNES,Vec*,PetscErrorCode (**SNESFunction)(SNES,Vec,Vec,void*),void**);
321 PETSC_EXTERN PetscErrorCode SNESComputeFunction(SNES,Vec,Vec);
322 PETSC_EXTERN PetscErrorCode SNESSetJacobian(SNES,Mat,Mat,PetscErrorCode (*SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void*);
323 PETSC_EXTERN PetscErrorCode SNESGetJacobian(SNES,Mat*,Mat*,PetscErrorCode (**SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void**);
324 PETSC_EXTERN PetscErrorCode SNESObjectiveComputeFunctionDefaultFD(SNES,Vec,Vec,void*);
325 PETSC_EXTERN PetscErrorCode SNESComputeJacobianDefault(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
326 PETSC_EXTERN PetscErrorCode SNESComputeJacobianDefaultColor(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
327 PETSC_EXTERN PetscErrorCode SNESSetComputeInitialGuess(SNES,PetscErrorCode (*)(SNES,Vec,void*),void*);
328 PETSC_EXTERN PetscErrorCode SNESSetPicard(SNES,Vec,PetscErrorCode (*SNESFunction)(SNES,Vec,Vec,void*),Mat,Mat,PetscErrorCode (*SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void*);
329 PETSC_EXTERN PetscErrorCode SNESGetPicard(SNES,Vec*,PetscErrorCode (**SNESFunction)(SNES,Vec,Vec,void*),Mat*,Mat*,PetscErrorCode (**SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void**);
330 PETSC_EXTERN PetscErrorCode SNESSetInitialFunction(SNES,Vec);
331 PETSC_EXTERN PetscErrorCode SNESSetInitialFunctionNorm(SNES,PetscReal);
332 
333 PETSC_EXTERN PetscErrorCode SNESSetObjective(SNES,PetscErrorCode (*SNESObjectiveFunction)(SNES,Vec,PetscReal *,void*),void*);
334 PETSC_EXTERN PetscErrorCode SNESGetObjective(SNES,PetscErrorCode (**SNESObjectiveFunction)(SNES,Vec,PetscReal *,void*),void**);
335 PETSC_EXTERN PetscErrorCode SNESComputeObjective(SNES,Vec,PetscReal *);
336 
337 /*E
338     SNESNormType - Norm that is passed in the Krylov convergence
339        test routines.
340 
341    Level: advanced
342 
343    Support for these is highly dependent on the solver.
344 
345    Notes:
346    This is primarily used to turn off extra norm and function computation
347    when the solvers are composed.
348 
349 .seealso: SNESSolve(), SNESGetConvergedReason(), KSPSetNormType(),
350           KSPSetConvergenceTest(), KSPSetPCSide()
351 E*/
352 
353 typedef enum {SNES_NORM_DEFAULT            = -1,
354               SNES_NORM_NONE               =  0,
355               SNES_NORM_FUNCTION           =  1,
356               SNES_NORM_INITIAL_ONLY       =  2,
357               SNES_NORM_FINAL_ONLY         =  3,
358               SNES_NORM_INITIAL_FINAL_ONLY =  4} SNESNormType;
359 PETSC_EXTERN const char *const*const SNESNormTypes;
360 /*MC
361     SNES_NORM_NONE - Don't compute function and its L2 norm.
362 
363    Level: advanced
364 
365     Notes:
366     This is most useful for stationary solvers with a fixed number of iterations used as smoothers.
367 
368 .seealso: SNESNormType, SNESSetNormType(), SNES_NORM_DEFAULT
369 M*/
370 
371 /*MC
372     SNES_NORM_FUNCTION - Compute the function and its L2 norm at each iteration.
373 
374    Level: advanced
375 
376     Notes:
377     Most solvers will use this no matter what norm type is passed to them.
378 
379 .seealso: SNESNormType, SNESSetNormType(), SNES_NORM_NONE
380 M*/
381 
382 /*MC
383     SNES_NORM_INITIAL_ONLY - Compute the function and its L2 at iteration 0, but do not update it.
384 
385    Level: advanced
386 
387    Notes:
388    This method is useful in composed methods, when a true solution might actually be found before SNESSolve() is called.
389    This option enables the solve to abort on the zeroth iteration if this is the case.
390 
391    For solvers that require the computation of the L2 norm of the function as part of the method, this merely cancels
392    the norm computation at the last iteration (if possible).
393 
394 .seealso: SNESNormType, SNESSetNormType(), SNES_NORM_FINAL_ONLY, SNES_NORM_INITIAL_FINAL_ONLY
395 M*/
396 
397 /*MC
398     SNES_NORM_FINAL_ONLY - Compute the function and its L2 norm on only the final iteration.
399 
400    Level: advanced
401 
402    Notes:
403    For solvers that require the computation of the L2 norm of the function as part of the method, behaves
404    exactly as SNES_NORM_DEFAULT.  This method is useful when the function is gotten after SNESSolve and
405    used in subsequent computation for methods that do not need the norm computed during the rest of the
406    solution procedure.
407 
408 .seealso: SNESNormType, SNESSetNormType(), SNES_NORM_INITIAL_ONLY, SNES_NORM_INITIAL_FINAL_ONLY
409 M*/
410 
411 /*MC
412     SNES_NORM_INITIAL_FINAL_ONLY - Compute the function and its L2 norm on only the initial and final iterations.
413 
414    Level: advanced
415 
416    Notes:
417    This method combines the benefits of SNES_NORM_INITIAL_ONLY and SNES_NORM_FINAL_ONLY.
418 
419 .seealso: SNESNormType, SNESSetNormType(), SNES_NORM_SNES_NORM_INITIAL_ONLY, SNES_NORM_FINAL_ONLY
420 M*/
421 
422 
423 PETSC_EXTERN PetscErrorCode SNESSetNormType(SNES,SNESNormType);
424 PETSC_EXTERN PetscErrorCode SNESGetNormType(SNES,SNESNormType*);
425 
426 PETSC_EXTERN PetscErrorCode SNESSetGS(SNES,PetscErrorCode (*SNESGSFunction)(SNES,Vec,Vec,void*),void*);
427 PETSC_EXTERN PetscErrorCode SNESGetGS(SNES,PetscErrorCode (**SNESGSFunction)(SNES,Vec,Vec,void*),void**);
428 PETSC_EXTERN PetscErrorCode SNESSetUseGS(SNES,PetscBool);
429 PETSC_EXTERN PetscErrorCode SNESGetUseGS(SNES,PetscBool *);
430 PETSC_EXTERN PetscErrorCode SNESComputeGS(SNES,Vec,Vec);
431 
432 PETSC_EXTERN PetscErrorCode SNESGSSetSweeps(SNES,PetscInt);
433 PETSC_EXTERN PetscErrorCode SNESGSGetSweeps(SNES,PetscInt *);
434 PETSC_EXTERN PetscErrorCode SNESGSSetTolerances(SNES,PetscReal,PetscReal,PetscReal,PetscInt);
435 PETSC_EXTERN PetscErrorCode SNESGSGetTolerances(SNES,PetscReal*,PetscReal*,PetscReal*,PetscInt*);
436 
437 PETSC_EXTERN PetscErrorCode SNESUpdateCheckJacobian(SNES,PetscInt);
438 
439 PETSC_EXTERN PetscErrorCode SNESShellGetContext(SNES,void**);
440 PETSC_EXTERN PetscErrorCode SNESShellSetContext(SNES,void*);
441 PETSC_EXTERN PetscErrorCode SNESShellSetSolve(SNES,PetscErrorCode (*)(SNES,Vec));
442 
443 /* --------- Routines specifically for line search methods --------------- */
444 
445 typedef struct _p_LineSearch* SNESLineSearch;
446 
447 /*S
448      SNESLineSearch - Abstract PETSc object that manages line-search operations
449 
450    Level: beginner
451 
452   Concepts: nonlinear solvers, line search
453 
454 .seealso:  SNESLineSearchCreate(), SNESLineSearchSetType(), SNES
455 S*/
456 
457 /*J
458     SNESLineSearchType - String with the name of a PETSc line search method
459 
460    Level: beginner
461 
462 .seealso: SNESLineSearchSetType(), SNES
463 J*/
464 
465 typedef const char* SNESLineSearchType;
466 #define SNESLINESEARCHBT                 "bt"
467 #define SNESLINESEARCHBASIC              "basic"
468 #define SNESLINESEARCHL2                 "l2"
469 #define SNESLINESEARCHCP                 "cp"
470 #define SNESLINESEARCHSHELL              "shell"
471 
472 PETSC_EXTERN PetscBool         SNESRegisterAllCalled;
473 PETSC_EXTERN PetscFunctionList SNESList;
474 PETSC_EXTERN PetscClassId      SNESLINESEARCH_CLASSID;
475 PETSC_EXTERN PetscBool         SNESLineSearchRegisterAllCalled;
476 PETSC_EXTERN PetscFunctionList SNESLineSearchList;
477 PETSC_EXTERN PetscLogEvent     SNESLineSearch_Apply;
478 
479 #define SNES_LINESEARCH_ORDER_LINEAR    1
480 #define SNES_LINESEARCH_ORDER_QUADRATIC 2
481 #define SNES_LINESEARCH_ORDER_CUBIC     3
482 
483 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*SNESLineSearchVIProjectFunc)(SNES,Vec);
484 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*SNESLineSearchVINormFunc)(SNES,Vec,Vec,PetscReal *);
485 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*SNESLineSearchApplyFunc)(SNESLineSearch);
486 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*SNESLineSearchUserFunc)(SNESLineSearch, void *);
487 
488 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate(MPI_Comm, SNESLineSearch*);
489 PETSC_EXTERN PetscErrorCode SNESLineSearchReset(SNESLineSearch);
490 PETSC_EXTERN PetscErrorCode SNESLineSearchView(SNESLineSearch,PetscViewer);
491 PETSC_EXTERN PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *);
492 PETSC_EXTERN PetscErrorCode SNESLineSearchSetType(SNESLineSearch, SNESLineSearchType);
493 PETSC_EXTERN PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch);
494 PETSC_EXTERN PetscErrorCode SNESLineSearchSetUp(SNESLineSearch);
495 PETSC_EXTERN PetscErrorCode SNESLineSearchApply(SNESLineSearch, Vec, Vec, PetscReal *, Vec);
496 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch,Vec,Vec,PetscBool *);
497 PETSC_EXTERN PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch,Vec,Vec,Vec,PetscBool *,PetscBool *);
498 PETSC_EXTERN PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch, PetscInt);
499 
500 /* set the functions for precheck and postcheck */
501 
502 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch, PetscErrorCode (*SNESLineSearchPreCheckFunction)(SNESLineSearch,Vec,Vec,PetscBool*,void*), void *ctx);
503 PETSC_EXTERN PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch, PetscErrorCode (*SNESLineSearchPostCheckFunction)(SNESLineSearch,Vec,Vec,Vec,PetscBool *,PetscBool *,void*), void *ctx);
504 
505 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch, PetscErrorCode (**SNESLineSearchPreCheckFunction)(SNESLineSearch,Vec,Vec,PetscBool*,void*), void **ctx);
506 PETSC_EXTERN PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch, PetscErrorCode (**SNESLineSearchPostCheckFunction)(SNESLineSearch,Vec,Vec,Vec,PetscBool *,PetscBool *,void*), void **ctx);
507 
508 /* set the functions for VI-specific line search operations */
509 
510 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFunc, SNESLineSearchVINormFunc);
511 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch, SNESLineSearchVIProjectFunc*, SNESLineSearchVINormFunc*);
512 
513 /* pointers to the associated SNES in order to be able to get the function evaluation out */
514 PETSC_EXTERN PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch,SNES);
515 PETSC_EXTERN PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch,SNES*);
516 
517 /* set and get the parameters and vectors */
518 PETSC_EXTERN PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch,PetscReal*,PetscReal*,PetscReal*,PetscReal*,PetscReal*,PetscInt*);
519 PETSC_EXTERN PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch,PetscReal,PetscReal,PetscReal,PetscReal,PetscReal,PetscInt);
520 
521 PETSC_EXTERN PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch,Vec,Vec,PetscBool*,void*);
522 
523 PETSC_EXTERN PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch,PetscReal*);
524 PETSC_EXTERN PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch,PetscReal);
525 
526 PETSC_EXTERN PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch,PetscReal*);
527 PETSC_EXTERN PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch,PetscReal);
528 
529 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch,PetscInt *order);
530 PETSC_EXTERN PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch,PetscInt order);
531 
532 PETSC_EXTERN PetscErrorCode SNESLineSearchGetSuccess(SNESLineSearch, PetscBool*);
533 PETSC_EXTERN PetscErrorCode SNESLineSearchSetSuccess(SNESLineSearch, PetscBool);
534 
535 PETSC_EXTERN PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch,Vec*,Vec*,Vec*,Vec*,Vec*);
536 PETSC_EXTERN PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch,Vec,Vec,Vec,Vec,Vec);
537 
538 PETSC_EXTERN PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch, PetscReal *, PetscReal *, PetscReal *);
539 PETSC_EXTERN PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch, PetscReal, PetscReal, PetscReal);
540 PETSC_EXTERN PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch);
541 PETSC_EXTERN PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch, PetscBool);
542 
543 PETSC_EXTERN PetscErrorCode SNESLineSearchSetMonitor(SNESLineSearch, PetscBool);
544 PETSC_EXTERN PetscErrorCode SNESLineSearchGetMonitor(SNESLineSearch, PetscViewer*);
545 
546 PETSC_EXTERN PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch, const char prefix[]);
547 PETSC_EXTERN PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch, const char *prefix[]);
548 
549 
550 /* Shell interface functions */
551 PETSC_EXTERN PetscErrorCode SNESLineSearchShellSetUserFunc(SNESLineSearch,SNESLineSearchUserFunc,void*);
552 PETSC_EXTERN PetscErrorCode SNESLineSearchShellGetUserFunc(SNESLineSearch,SNESLineSearchUserFunc*,void**);
553 
554 /* BT interface functions */
555 PETSC_EXTERN PetscErrorCode SNESLineSearchBTSetAlpha(SNESLineSearch, PetscReal);
556 PETSC_EXTERN PetscErrorCode SNESLineSearchBTGetAlpha(SNESLineSearch, PetscReal*);
557 
558 /*register line search types */
559 PETSC_EXTERN PetscErrorCode SNESLineSearchRegister(const char[],PetscErrorCode(*)(SNESLineSearch));
560 PETSC_EXTERN PetscErrorCode SNESLineSearchRegisterAll(void);
561 
562 /* Routines for VI solver */
563 PETSC_EXTERN PetscErrorCode SNESVISetVariableBounds(SNES,Vec,Vec);
564 PETSC_EXTERN PetscErrorCode SNESVISetComputeVariableBounds(SNES, PetscErrorCode (*)(SNES,Vec,Vec));
565 PETSC_EXTERN PetscErrorCode SNESVIGetInactiveSet(SNES,IS*);
566 PETSC_EXTERN PetscErrorCode SNESVIGetActiveSetIS(SNES,Vec,Vec,IS*);
567 PETSC_EXTERN PetscErrorCode SNESVIComputeInactiveSetFnorm(SNES,Vec,Vec,PetscReal*);
568 PETSC_EXTERN PetscErrorCode SNESVISetRedundancyCheck(SNES,PetscErrorCode(*)(SNES,IS,IS*,void*),void*);
569 #define SNES_VI_INF   1.0e20
570 #define SNES_VI_NINF -1.0e20
571 
572 PETSC_EXTERN PetscErrorCode SNESTestLocalMin(SNES);
573 
574 /* Should this routine be private? */
575 PETSC_EXTERN PetscErrorCode SNESComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*);
576 
577 PETSC_EXTERN PetscErrorCode SNESSetDM(SNES,DM);
578 PETSC_EXTERN PetscErrorCode SNESGetDM(SNES,DM*);
579 PETSC_EXTERN PetscErrorCode SNESSetPC(SNES,SNES);
580 PETSC_EXTERN PetscErrorCode SNESGetPC(SNES,SNES*);
581 PETSC_EXTERN PetscErrorCode SNESSetPCSide(SNES,PCSide);
582 PETSC_EXTERN PetscErrorCode SNESGetPCSide(SNES,PCSide*);
583 PETSC_EXTERN PetscErrorCode SNESSetLineSearch(SNES,SNESLineSearch);
584 PETSC_EXTERN PetscErrorCode SNESGetLineSearch(SNES,SNESLineSearch*);
585 PETSC_EXTERN PetscErrorCode SNESRestrictHookAdd(SNES,PetscErrorCode (*)(SNES,SNES,void*),void*);
586 PETSC_EXTERN PetscErrorCode SNESRestrictHooksRun(SNES,SNES);
587 
588 PETSC_DEPRECATED("Use SNESGetLineSearch()") PETSC_STATIC_INLINE PetscErrorCode SNESGetSNESLineSearch(SNES snes,SNESLineSearch *ls) {return SNESGetLineSearch(snes,ls);}
589 PETSC_DEPRECATED("Use SNESSetLineSearch()") PETSC_STATIC_INLINE PetscErrorCode SNESSetSNESLineSearch(SNES snes,SNESLineSearch ls) {return SNESSetLineSearch(snes,ls);}
590 
591 PETSC_EXTERN PetscErrorCode SNESSetUpMatrices(SNES);
592 PETSC_EXTERN PetscErrorCode DMSNESSetFunction(DM,PetscErrorCode(*SNESFunction)(SNES,Vec,Vec,void*),void*);
593 PETSC_EXTERN PetscErrorCode DMSNESGetFunction(DM,PetscErrorCode(**SNESSetFunction)(SNES,Vec,Vec,void*),void**);
594 PETSC_EXTERN PetscErrorCode DMSNESSetGS(DM,PetscErrorCode(*SNESGSFunction)(SNES,Vec,Vec,void*),void*);
595 PETSC_EXTERN PetscErrorCode DMSNESGetGS(DM,PetscErrorCode(**SNESGSFunction)(SNES,Vec,Vec,void*),void**);
596 PETSC_EXTERN PetscErrorCode DMSNESSetJacobian(DM,PetscErrorCode(*SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void*);
597 PETSC_EXTERN PetscErrorCode DMSNESGetJacobian(DM,PetscErrorCode(**SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void**);
598 PETSC_EXTERN PetscErrorCode DMSNESSetPicard(DM,PetscErrorCode(*SNESFunction)(SNES,Vec,Vec,void*),PetscErrorCode(*SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void*);
599 PETSC_EXTERN PetscErrorCode DMSNESGetPicard(DM,PetscErrorCode(**SNESFunction)(SNES,Vec,Vec,void*),PetscErrorCode(**SNESJacobianFunction)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void**);
600 PETSC_EXTERN PetscErrorCode DMSNESSetObjective(DM,PetscErrorCode (*SNESObjectiveFunction)(SNES,Vec,PetscReal *,void*),void*);
601 PETSC_EXTERN PetscErrorCode DMSNESGetObjective(DM,PetscErrorCode (**SNESObjectiveFunction)(SNES,Vec,PetscReal *,void*),void**);
602 
603 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*DMDASNESFunction)(DMDALocalInfo*,void*,void*,void*);
604 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*DMDASNESJacobian)(DMDALocalInfo*,void*,Mat,Mat,MatStructure*,void*);
605 PETSC_EXTERN_TYPEDEF typedef PetscErrorCode (*DMDASNESObjective)(DMDALocalInfo*,void*,PetscReal*,void*);
606 
607 PETSC_EXTERN PetscErrorCode DMDASNESSetFunctionLocal(DM,InsertMode,DMDASNESFunction,void*);
608 PETSC_EXTERN PetscErrorCode DMDASNESSetJacobianLocal(DM,DMDASNESJacobian,void*);
609 PETSC_EXTERN PetscErrorCode DMDASNESSetObjectiveLocal(DM,DMDASNESObjective,void*);
610 PETSC_EXTERN PetscErrorCode DMDASNESSetPicardLocal(DM,InsertMode,PetscErrorCode (*)(DMDALocalInfo*,void*,void*,void*),PetscErrorCode (*)(DMDALocalInfo*,void*,Mat,Mat,MatStructure*,void*),void*);
611 
612 PETSC_EXTERN PetscErrorCode DMSNESSetFunctionLocal(DM,PetscErrorCode (*)(DM,Vec,Vec,void*),void*);
613 PETSC_EXTERN PetscErrorCode DMSNESSetJacobianLocal(DM,PetscErrorCode (*)(DM,Vec,Mat,Mat,MatStructure*,void*),void*);
614 
615 /* Routines for Multiblock solver */
616 PETSC_EXTERN PetscErrorCode SNESMultiblockSetFields(SNES, const char [], PetscInt, const PetscInt *);
617 PETSC_EXTERN PetscErrorCode SNESMultiblockSetIS(SNES, const char [], IS);
618 PETSC_EXTERN PetscErrorCode SNESMultiblockSetBlockSize(SNES, PetscInt);
619 PETSC_EXTERN PetscErrorCode SNESMultiblockSetType(SNES, PCCompositeType);
620 
621 /*J
622     SNESMSType - String with the name of a PETSc SNESMS method.
623 
624    Level: intermediate
625 
626 .seealso: SNESMSSetType(), SNES
627 J*/
628 typedef const char* SNESMSType;
629 #define SNESMSM62       "m62"
630 #define SNESMSEULER     "euler"
631 #define SNESMSJAMESON83 "jameson83"
632 #define SNESMSVLTP21    "vltp21"
633 #define SNESMSVLTP31    "vltp31"
634 #define SNESMSVLTP41    "vltp41"
635 #define SNESMSVLTP51    "vltp51"
636 #define SNESMSVLTP61    "vltp61"
637 
638 PETSC_EXTERN PetscErrorCode SNESMSRegister(SNESMSType,PetscInt,PetscInt,PetscReal,const PetscReal[],const PetscReal[],const PetscReal[]);
639 PETSC_EXTERN PetscErrorCode SNESMSSetType(SNES,SNESMSType);
640 PETSC_EXTERN PetscErrorCode SNESMSFinalizePackage(void);
641 PETSC_EXTERN PetscErrorCode SNESMSInitializePackage(void);
642 PETSC_EXTERN PetscErrorCode SNESMSRegisterDestroy(void);
643 PETSC_EXTERN PetscErrorCode SNESMSRegisterAll(void);
644 
645 /* routines for NGMRES solver */
646 
647 typedef enum {
648   SNES_NGMRES_RESTART_NONE       = 0,
649   SNES_NGMRES_RESTART_PERIODIC   = 1,
650   SNES_NGMRES_RESTART_DIFFERENCE = 2} SNESNGMRESRestartType;
651 PETSC_EXTERN const char *const SNESNGMRESRestartTypes[];
652 
653 typedef enum {
654   SNES_NGMRES_SELECT_NONE       = 0,
655   SNES_NGMRES_SELECT_DIFFERENCE = 1,
656   SNES_NGMRES_SELECT_LINESEARCH = 2} SNESNGMRESSelectType;
657 PETSC_EXTERN const char *const SNESNGMRESSelectTypes[];
658 
659 PETSC_EXTERN PetscErrorCode SNESNGMRESSetRestartType(SNES, SNESNGMRESRestartType);
660 PETSC_EXTERN PetscErrorCode SNESNGMRESSetSelectType(SNES, SNESNGMRESSelectType);
661 
662 /* routines for NCG solver */
663 
664 typedef enum {
665   SNES_NCG_FR    = 0,
666   SNES_NCG_PRP   = 1,
667   SNES_NCG_HS    = 2,
668   SNES_NCG_DY    = 3,
669   SNES_NCG_CD    = 4} SNESNCGType;
670 PETSC_EXTERN const char *const SNESNCGTypes[];
671 
672 PETSC_EXTERN PetscErrorCode SNESNCGSetType(SNES, SNESNCGType);
673 
674 typedef enum {SNES_QN_SCALE_NONE       = 0,
675               SNES_QN_SCALE_SHANNO     = 1,
676               SNES_QN_SCALE_LINESEARCH = 2,
677               SNES_QN_SCALE_JACOBIAN   = 3} SNESQNScaleType;
678 PETSC_EXTERN const char *const SNESQNScaleTypes[];
679 typedef enum {SNES_QN_RESTART_NONE     = 0,
680               SNES_QN_RESTART_POWELL   = 1,
681               SNES_QN_RESTART_PERIODIC = 2} SNESQNRestartType;
682 PETSC_EXTERN const char *const SNESQNRestartTypes[];
683 
684 PETSC_EXTERN PetscErrorCode SNESQNSetScaleType(SNES, SNESQNScaleType);
685 PETSC_EXTERN PetscErrorCode SNESQNSetRestartType(SNES, SNESQNRestartType);
686 
687 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomains(SNES,PetscInt*,SNES**,VecScatter**,VecScatter**,VecScatter**);
688 PETSC_EXTERN PetscErrorCode SNESNASMSetSubdomains(SNES,PetscInt,SNES*,VecScatter*,VecScatter*,VecScatter*);
689 PETSC_EXTERN PetscErrorCode SNESNASMGetSubdomainVecs(SNES,PetscInt*,Vec**,Vec**,Vec**,Vec**);
690 PETSC_EXTERN PetscErrorCode SNESNASMSetComputeFinalJacobian(SNES,PetscBool);
691 
692 typedef enum {SNES_COMPOSITE_ADDITIVE,SNES_COMPOSITE_MULTIPLICATIVE,SNES_COMPOSITE_ADDITIVEOPTIMAL} SNESCompositeType;
693 PETSC_EXTERN const char *const SNESCompositeTypes[];
694 
695 PETSC_EXTERN PetscErrorCode SNESCompositeSetType(SNES,SNESCompositeType);
696 PETSC_EXTERN PetscErrorCode SNESCompositeAddSNES(SNES,SNESType);
697 PETSC_EXTERN PetscErrorCode SNESCompositeGetSNES(SNES,PetscInt,SNES *);
698 PETSC_EXTERN PetscErrorCode SNESCompositeSetDamping(SNES,PetscInt,PetscReal);
699 
700 #endif
701