173f4d377SMatthew Knepley /* $Id: petscsnes.h,v 1.111 2001/08/06 21:17:05 bsmith Exp $ */ 2f26ada1bSBarry Smith /* 3eef9c623SLois Curfman McInnes User interface for the nonlinear solvers package. 4f26ada1bSBarry Smith */ 50a835dfdSSatish Balay #if !defined(__PETSCSNES_H) 60a835dfdSSatish Balay #define __PETSCSNES_H 70a835dfdSSatish Balay #include "petscsles.h" 8*e9fa29b7SSatish Balay PETSC_EXTERN_CXX_BEGIN 9b1f5cb9dSBarry Smith 10435da068SBarry Smith /*S 11435da068SBarry Smith SNES - Abstract PETSc object that manages all nonlinear solves 12435da068SBarry Smith 13435da068SBarry Smith Level: beginner 14435da068SBarry Smith 15435da068SBarry Smith Concepts: nonlinear solvers 16435da068SBarry Smith 17eef9c623SLois Curfman McInnes .seealso: SNESCreate(), SNESSetType(), SNESType, TS, SLES, KSP, PC 18435da068SBarry Smith S*/ 19f09e8eb9SSatish Balay typedef struct _p_SNES* SNES; 20435da068SBarry Smith 21435da068SBarry Smith /*E 22435da068SBarry Smith SNESType - String with the name of a PETSc SNES method or the creation function 23435da068SBarry Smith with an optional dynamic library name, for example 24435da068SBarry Smith http://www.mcs.anl.gov/petsc/lib.a:mysnescreate() 25435da068SBarry Smith 26435da068SBarry Smith Level: beginner 27435da068SBarry Smith 28435da068SBarry Smith .seealso: SNESSetType(), SNES 29435da068SBarry Smith E*/ 30eef9c623SLois Curfman McInnes #define SNESLS "ls" 31eef9c623SLois Curfman McInnes #define SNESTR "tr" 32eef9c623SLois Curfman McInnes #define SNESTEST "test" 3382bf6240SBarry Smith typedef char *SNESType; 34b1f5cb9dSBarry Smith 35deeb6e72SMatthew Knepley /* Logging support */ 36deeb6e72SMatthew Knepley extern int SNES_COOKIE; 37eef9c623SLois Curfman McInnes extern int SNES_Solve, SNES_LineSearch, SNES_FunctionEval, SNES_JacobianEval; 38eef9c623SLois Curfman McInnes 39deeb6e72SMatthew Knepley 401836bdbcSSatish Balay EXTERN int SNESInitializePackage(const char[]); 41deeb6e72SMatthew Knepley 42eef9c623SLois Curfman McInnes EXTERN int SNESCreate(MPI_Comm,SNES*); 43ca44d042SBarry Smith EXTERN int SNESDestroy(SNES); 44ca44d042SBarry Smith EXTERN int SNESSetType(SNES,SNESType); 4587828ca2SBarry Smith EXTERN int SNESSetMonitor(SNES,int(*)(SNES,int,PetscReal,void*),void *,int (*)(void *)); 46ca44d042SBarry Smith EXTERN int SNESClearMonitor(SNES); 471836bdbcSSatish Balay EXTERN int SNESSetConvergenceHistory(SNES,PetscReal[],int[],int,PetscTruth); 481836bdbcSSatish Balay EXTERN int SNESGetConvergenceHistory(SNES,PetscReal*[],int *[],int *); 49ca44d042SBarry Smith EXTERN int SNESSetUp(SNES,Vec); 50ca44d042SBarry Smith EXTERN int SNESSolve(SNES,Vec,int*); 5184cb2905SBarry Smith 524d8f6ca9SMatthew Knepley EXTERN int SNESAddOptionsChecker(int (*)(SNES)); 534d8f6ca9SMatthew Knepley 544d8f6ca9SMatthew Knepley EXTERN int SNESSetRhsBC(SNES, int (*)(SNES, Vec, void *)); 554d8f6ca9SMatthew Knepley EXTERN int SNESDefaultRhsBC(SNES, Vec, void *); 564d8f6ca9SMatthew Knepley EXTERN int SNESSetSolutionBC(SNES, int (*)(SNES, Vec, void *)); 574d8f6ca9SMatthew Knepley EXTERN int SNESDefaultSolutionBC(SNES, Vec, void *); 584d8f6ca9SMatthew Knepley EXTERN int SNESSetUpdate(SNES, int (*)(SNES, int)); 594d8f6ca9SMatthew Knepley EXTERN int SNESDefaultUpdate(SNES, int); 604d8f6ca9SMatthew Knepley 61b0a32e0cSBarry Smith extern PetscFList SNESList; 62ca44d042SBarry Smith EXTERN int SNESRegisterDestroy(void); 631836bdbcSSatish Balay EXTERN int SNESRegisterAll(const char[]); 6484cb2905SBarry Smith 651836bdbcSSatish Balay EXTERN int SNESRegister(const char[],const char[],const char[],int(*)(SNES)); 6630de9b25SBarry Smith 6730de9b25SBarry Smith /*MC 6830de9b25SBarry Smith SNESRegisterDynamic - Adds a method to the nonlinear solver package. 6930de9b25SBarry Smith 7030de9b25SBarry Smith Synopsis: 7130de9b25SBarry Smith int SNESRegisterDynamic(char *name_solver,char *path,char *name_create,int (*routine_create)(SNES)) 7230de9b25SBarry Smith 7330de9b25SBarry Smith Not collective 7430de9b25SBarry Smith 7530de9b25SBarry Smith Input Parameters: 7630de9b25SBarry Smith + name_solver - name of a new user-defined solver 7730de9b25SBarry Smith . path - path (either absolute or relative) the library containing this solver 7830de9b25SBarry Smith . name_create - name of routine to create method context 7930de9b25SBarry Smith - routine_create - routine to create method context 8030de9b25SBarry Smith 8130de9b25SBarry Smith Notes: 8230de9b25SBarry Smith SNESRegisterDynamic() may be called multiple times to add several user-defined solvers. 8330de9b25SBarry Smith 8430de9b25SBarry Smith If dynamic libraries are used, then the fourth input argument (routine_create) 8530de9b25SBarry Smith is ignored. 8630de9b25SBarry Smith 8730de9b25SBarry Smith Environmental variables such as ${PETSC_ARCH}, ${PETSC_DIR}, ${PETSC_LIB_DIR}, ${BOPT}, 8830de9b25SBarry Smith and others of the form ${any_environmental_variable} occuring in pathname will be 8930de9b25SBarry Smith replaced with appropriate values. 9030de9b25SBarry Smith 9130de9b25SBarry Smith Sample usage: 9230de9b25SBarry Smith .vb 9330de9b25SBarry Smith SNESRegisterDynamic("my_solver",/home/username/my_lib/lib/libg/solaris/mylib.a, 9430de9b25SBarry Smith "MySolverCreate",MySolverCreate); 9530de9b25SBarry Smith .ve 9630de9b25SBarry Smith 9730de9b25SBarry Smith Then, your solver can be chosen with the procedural interface via 9830de9b25SBarry Smith $ SNESSetType(snes,"my_solver") 9930de9b25SBarry Smith or at runtime via the option 10030de9b25SBarry Smith $ -snes_type my_solver 10130de9b25SBarry Smith 10230de9b25SBarry Smith Level: advanced 10330de9b25SBarry Smith 10430de9b25SBarry Smith Note: If your function is not being put into a shared library then use SNESRegister() instead 10530de9b25SBarry Smith 10630de9b25SBarry Smith .keywords: SNES, nonlinear, register 10730de9b25SBarry Smith 10830de9b25SBarry Smith .seealso: SNESRegisterAll(), SNESRegisterDestroy() 10930de9b25SBarry Smith M*/ 110aa482453SBarry Smith #if defined(PETSC_USE_DYNAMIC_LIBRARIES) 111f1af5d2fSBarry Smith #define SNESRegisterDynamic(a,b,c,d) SNESRegister(a,b,c,0) 112b2002411SLois Curfman McInnes #else 113f1af5d2fSBarry Smith #define SNESRegisterDynamic(a,b,c,d) SNESRegister(a,b,c,d) 114b2002411SLois Curfman McInnes #endif 115b2002411SLois Curfman McInnes 116ca44d042SBarry Smith EXTERN int SNESGetSLES(SNES,SLES*); 117ca44d042SBarry Smith EXTERN int SNESGetSolution(SNES,Vec*); 118ca44d042SBarry Smith EXTERN int SNESGetSolutionUpdate(SNES,Vec*); 1198439883dSBarry Smith EXTERN int SNESGetFunction(SNES,Vec*,void**,int(**)(SNES,Vec,Vec,void*)); 120b0a32e0cSBarry Smith EXTERN int SNESView(SNES,PetscViewer); 1217bc3d0afSSatish Balay 1221836bdbcSSatish Balay EXTERN int SNESSetOptionsPrefix(SNES,const char[]); 1231836bdbcSSatish Balay EXTERN int SNESAppendOptionsPrefix(SNES,const char[]); 1241836bdbcSSatish Balay EXTERN int SNESGetOptionsPrefix(SNES,char*[]); 125ca44d042SBarry Smith EXTERN int SNESSetFromOptions(SNES); 12640191667SLois Curfman McInnes 127ca44d042SBarry Smith EXTERN int MatCreateSNESMF(SNES,Vec,Mat*); 1281d1367b7SBarry Smith EXTERN int MatCreateMF(Vec,Mat*); 1291d1367b7SBarry Smith EXTERN int MatSNESMFSetBase(Mat,Vec); 1303a7fca6bSBarry Smith EXTERN int MatSNESMFComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 131ca44d042SBarry Smith EXTERN int MatSNESMFSetFunction(Mat,Vec,int(*)(SNES,Vec,Vec,void*),void*); 13287828ca2SBarry Smith EXTERN int MatSNESMFSetFunctioni(Mat,int (*)(int,Vec,PetscScalar*,void*)); 1338a124369SBarry Smith EXTERN int MatSNESMFSetFunctioniBase(Mat,int (*)(Vec,void*)); 13474637425SBarry Smith EXTERN int MatSNESMFAddNullSpace(Mat,MatNullSpace); 1351836bdbcSSatish Balay EXTERN int MatSNESMFSetHHistory(Mat,PetscScalar[],int); 136ca44d042SBarry Smith EXTERN int MatSNESMFResetHHistory(Mat); 13787828ca2SBarry Smith EXTERN int MatSNESMFSetFunctionError(Mat,PetscReal); 138ca44d042SBarry Smith EXTERN int MatSNESMFSetPeriod(Mat,int); 13987828ca2SBarry Smith EXTERN int MatSNESMFGetH(Mat,PetscScalar *); 14087828ca2SBarry Smith EXTERN int MatSNESMFKSPMonitor(KSP,int,PetscReal,void *); 141ca44d042SBarry Smith EXTERN int MatSNESMFSetFromOptions(Mat); 1425b7f0c42SBarry Smith EXTERN int MatSNESMFCheckPositivity(Vec,Vec,PetscScalar*,void*); 14361860be5SBarry Smith EXTERN int MatSNESMFSetCheckh(Mat,int (*)(Vec,Vec,PetscScalar*,void*),void*); 1445b7f0c42SBarry Smith 1455a655dc6SBarry Smith typedef struct _p_MatSNESMFCtx *MatSNESMFCtx; 146435da068SBarry Smith 147435da068SBarry Smith #define MATSNESMF_DEFAULT "default" 148435da068SBarry Smith #define MATSNESMF_WP "wp" 149b7fd4e64SBarry Smith typedef char* MatSNESMFType; 150ca44d042SBarry Smith EXTERN int MatSNESMFSetType(Mat,MatSNESMFType); 1511836bdbcSSatish Balay EXTERN int MatSNESMFRegister(const char[],const char[],const char[],int (*)(MatSNESMFCtx)); 15230de9b25SBarry Smith 15330de9b25SBarry Smith /*MC 15430de9b25SBarry Smith MatSNESMFRegisterDynamic - Adds a method to the MatSNESMF registry. 15530de9b25SBarry Smith 15630de9b25SBarry Smith Synopsis: 15730de9b25SBarry Smith int MatSNESMFRegisterDynamic(char *name_solver,char *path,char *name_create,int (*routine_create)(MatSNESMF)) 15830de9b25SBarry Smith 15930de9b25SBarry Smith Not Collective 16030de9b25SBarry Smith 16130de9b25SBarry Smith Input Parameters: 16230de9b25SBarry Smith + name_solver - name of a new user-defined compute-h module 16330de9b25SBarry Smith . path - path (either absolute or relative) the library containing this solver 16430de9b25SBarry Smith . name_create - name of routine to create method context 16530de9b25SBarry Smith - routine_create - routine to create method context 16630de9b25SBarry Smith 16730de9b25SBarry Smith Level: developer 16830de9b25SBarry Smith 16930de9b25SBarry Smith Notes: 17030de9b25SBarry Smith MatSNESMFRegisterDynamic) may be called multiple times to add several user-defined solvers. 17130de9b25SBarry Smith 17230de9b25SBarry Smith If dynamic libraries are used, then the fourth input argument (routine_create) 17330de9b25SBarry Smith is ignored. 17430de9b25SBarry Smith 17530de9b25SBarry Smith Sample usage: 17630de9b25SBarry Smith .vb 17730de9b25SBarry Smith MatSNESMFRegisterDynamic"my_h",/home/username/my_lib/lib/libO/solaris/mylib.a, 17830de9b25SBarry Smith "MyHCreate",MyHCreate); 17930de9b25SBarry Smith .ve 18030de9b25SBarry Smith 18130de9b25SBarry Smith Then, your solver can be chosen with the procedural interface via 18230de9b25SBarry Smith $ MatSNESMFSetType(mfctx,"my_h") 18330de9b25SBarry Smith or at runtime via the option 18430de9b25SBarry Smith $ -snes_mf_type my_h 18530de9b25SBarry Smith 18630de9b25SBarry Smith .keywords: MatSNESMF, register 18730de9b25SBarry Smith 18830de9b25SBarry Smith .seealso: MatSNESMFRegisterAll(), MatSNESMFRegisterDestroy() 18930de9b25SBarry Smith M*/ 190aa482453SBarry Smith #if defined(PETSC_USE_DYNAMIC_LIBRARIES) 191f1af5d2fSBarry Smith #define MatSNESMFRegisterDynamic(a,b,c,d) MatSNESMFRegister(a,b,c,0) 1929a6cb015SBarry Smith #else 193f1af5d2fSBarry Smith #define MatSNESMFRegisterDynamic(a,b,c,d) MatSNESMFRegister(a,b,c,d) 1949a6cb015SBarry Smith #endif 19530de9b25SBarry Smith 1961836bdbcSSatish Balay EXTERN int MatSNESMFRegisterAll(const char[]); 197ca44d042SBarry Smith EXTERN int MatSNESMFRegisterDestroy(void); 1983a7fca6bSBarry Smith EXTERN int MatSNESMFDefaultSetUmin(Mat,PetscReal); 199ca44d042SBarry Smith EXTERN int MatSNESMFWPSetComputeNormA(Mat,PetscTruth); 200ca44d042SBarry Smith EXTERN int MatSNESMFWPSetComputeNormU(Mat,PetscTruth); 2018f6e3e37SBarry Smith 2023a7fca6bSBarry Smith EXTERN int MatDAADSetSNES(Mat,SNES); 2033a7fca6bSBarry Smith 204ca44d042SBarry Smith EXTERN int SNESGetType(SNES,SNESType*); 20587828ca2SBarry Smith EXTERN int SNESDefaultMonitor(SNES,int,PetscReal,void *); 20687828ca2SBarry Smith EXTERN int SNESRatioMonitor(SNES,int,PetscReal,void *); 2073a7fca6bSBarry Smith EXTERN int SNESSetRatioMonitor(SNES); 20887828ca2SBarry Smith EXTERN int SNESVecViewMonitor(SNES,int,PetscReal,void *); 2095ed2d596SBarry Smith EXTERN int SNESVecViewResidualMonitor(SNES,int,PetscReal,void *); 21087828ca2SBarry Smith EXTERN int SNESVecViewUpdateMonitor(SNES,int,PetscReal,void *); 21187828ca2SBarry Smith EXTERN int SNESDefaultSMonitor(SNES,int,PetscReal,void *); 21287828ca2SBarry Smith EXTERN int SNESSetTolerances(SNES,PetscReal,PetscReal,PetscReal,int,int); 21387828ca2SBarry Smith EXTERN int SNESGetTolerances(SNES,PetscReal*,PetscReal*,PetscReal*,int*,int*); 21487828ca2SBarry Smith EXTERN int SNESSetTrustRegionTolerance(SNES,PetscReal); 215ca44d042SBarry Smith EXTERN int SNESGetIterationNumber(SNES,int*); 21687828ca2SBarry Smith EXTERN int SNESGetFunctionNorm(SNES,PetscScalar*); 217ca44d042SBarry Smith EXTERN int SNESGetNumberUnsuccessfulSteps(SNES,int*); 2183064298fSMatthew Knepley EXTERN int SNESSetMaximumUnsuccessfulSteps(SNES,int); 2193064298fSMatthew Knepley EXTERN int SNESGetMaximumUnsuccessfulSteps(SNES,int*); 220ca44d042SBarry Smith EXTERN int SNESGetNumberLinearIterations(SNES,int*); 22187828ca2SBarry Smith EXTERN int SNES_KSP_SetParametersEW(SNES,int,PetscReal,PetscReal,PetscReal,PetscReal,PetscReal,PetscReal); 222ca44d042SBarry Smith EXTERN int SNES_KSP_SetConvergenceTestEW(SNES); 223eafb4bcbSBarry Smith 2243369ce9aSBarry Smith /* 2253369ce9aSBarry Smith Reuse the default KSP monitor routines for SNES 2263369ce9aSBarry Smith */ 2271836bdbcSSatish Balay EXTERN int SNESLGMonitorCreate(const char[],const char[],int,int,int,int,PetscDrawLG*); 22887828ca2SBarry Smith EXTERN int SNESLGMonitor(SNES,int,PetscReal,void*); 229b0a32e0cSBarry Smith EXTERN int SNESLGMonitorDestroy(PetscDrawLG); 230eafb4bcbSBarry Smith 231ca44d042SBarry Smith EXTERN int SNESSetApplicationContext(SNES,void *); 232ca44d042SBarry Smith EXTERN int SNESGetApplicationContext(SNES,void **); 233184914b5SBarry Smith 234435da068SBarry Smith /*E 235435da068SBarry Smith SNESConvergedReason - reason a SNES method was said to 236435da068SBarry Smith have converged or diverged 237435da068SBarry Smith 238435da068SBarry Smith Level: beginner 239435da068SBarry Smith 240435da068SBarry Smith Notes: this must match finclude/petscsnes.h 241435da068SBarry Smith 242435da068SBarry Smith .seealso: SNESSolve(), SNESGetConvergedReason(), KSPConvergedReason, SNESSetConvergenceTest() 243435da068SBarry Smith E*/ 244184914b5SBarry Smith typedef enum {/* converged */ 245184914b5SBarry Smith SNES_CONVERGED_FNORM_ABS = 2, /* F < F_minabs */ 246184914b5SBarry Smith SNES_CONVERGED_FNORM_RELATIVE = 3, /* F < F_mintol*F_initial */ 247184914b5SBarry Smith SNES_CONVERGED_PNORM_RELATIVE = 4, /* step size small */ 248184914b5SBarry Smith SNES_CONVERGED_GNORM_ABS = 5, /* grad F < grad F_min */ 249184914b5SBarry Smith SNES_CONVERGED_TR_REDUCTION = 6, 250184914b5SBarry Smith SNES_CONVERGED_TR_DELTA = 7, 251184914b5SBarry Smith /* diverged */ 252184914b5SBarry Smith SNES_DIVERGED_FUNCTION_COUNT = -2, 253184914b5SBarry Smith SNES_DIVERGED_FNORM_NAN = -4, 254184914b5SBarry Smith SNES_DIVERGED_MAX_IT = -5, 255184914b5SBarry Smith SNES_DIVERGED_LS_FAILURE = -6, 256184914b5SBarry Smith SNES_DIVERGED_TR_REDUCTION = -7, 25758c775ebSBarry Smith SNES_DIVERGED_LOCAL_MIN = -8, /* || J^T b || is small, implies converged to local minimum of F() */ 258184914b5SBarry Smith SNES_CONVERGED_ITERATING = 0} SNESConvergedReason; 259184914b5SBarry Smith 26087828ca2SBarry Smith EXTERN int SNESSetConvergenceTest(SNES,int (*)(SNES,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void*); 261eef9c623SLois Curfman McInnes EXTERN int SNESConverged_LS(SNES,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*); 262eef9c623SLois Curfman McInnes EXTERN int SNESConverged_TR(SNES,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*); 263ca44d042SBarry Smith EXTERN int SNESGetConvergedReason(SNES,SNESConvergedReason*); 264ddbbdb52SLois Curfman McInnes 2653a7fca6bSBarry Smith EXTERN int SNESDAFormFunction(SNES,Vec,Vec,void*); 2663a7fca6bSBarry Smith EXTERN int SNESDAComputeJacobianWithAdic(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 2673a7fca6bSBarry Smith EXTERN int SNESDAComputeJacobianWithAdifor(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 2683a7fca6bSBarry Smith EXTERN int SNESDAComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 2693a7fca6bSBarry Smith 270b67197daSBarry Smith /* --------- Solving systems of nonlinear equations --------------- */ 271ca44d042SBarry Smith EXTERN int SNESSetFunction(SNES,Vec,int(*)(SNES,Vec,Vec,void*),void *); 272ca44d042SBarry Smith EXTERN int SNESComputeFunction(SNES,Vec,Vec); 273ca44d042SBarry Smith EXTERN int SNESSetJacobian(SNES,Mat,Mat,int(*)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *); 2748439883dSBarry Smith EXTERN int SNESGetJacobian(SNES,Mat*,Mat*,void **,int(**)(SNES,Vec,Mat*,Mat*,MatStructure*,void*)); 275ca44d042SBarry Smith EXTERN int SNESDefaultComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 276ca44d042SBarry Smith EXTERN int SNESDefaultComputeJacobianColor(SNES,Vec,Mat*,Mat*,MatStructure*,void*); 27787828ca2SBarry Smith EXTERN int SNESSetLineSearch(SNES,int(*)(SNES,void*,Vec,Vec,Vec,Vec,Vec,PetscReal,PetscReal*,PetscReal*,int*),void*); 27887828ca2SBarry Smith EXTERN int SNESNoLineSearch(SNES,void*,Vec,Vec,Vec,Vec,Vec,PetscReal,PetscReal*,PetscReal*,int*); 27987828ca2SBarry Smith EXTERN int SNESNoLineSearchNoNorms(SNES,void*,Vec,Vec,Vec,Vec,Vec,PetscReal,PetscReal*,PetscReal*,int*); 28087828ca2SBarry Smith EXTERN int SNESCubicLineSearch(SNES,void*,Vec,Vec,Vec,Vec,Vec,PetscReal,PetscReal*,PetscReal*,int*); 28187828ca2SBarry Smith EXTERN int SNESQuadraticLineSearch(SNES,void*,Vec,Vec,Vec,Vec,Vec,PetscReal,PetscReal*,PetscReal*,int*); 282ca44d042SBarry Smith EXTERN int SNESSetLineSearchCheck(SNES,int(*)(SNES,void*,Vec,PetscTruth*),void*); 28387828ca2SBarry Smith EXTERN int SNESSetLineSearchParams(SNES,PetscReal,PetscReal,PetscReal); 28487828ca2SBarry Smith EXTERN int SNESGetLineSearchParams(SNES,PetscReal*,PetscReal*,PetscReal*); 28540191667SLois Curfman McInnes 286da9b6338SBarry Smith EXTERN int SNESTestLocalMin(SNES snes); 287da9b6338SBarry Smith 288eef9c623SLois Curfman McInnes /* Should this routine be private? */ 289ca44d042SBarry Smith EXTERN int SNESComputeJacobian(SNES,Vec,Mat*,Mat*,MatStructure*); 290ddbbdb52SLois Curfman McInnes 291*e9fa29b7SSatish Balay PETSC_EXTERN_CXX_END 292ce3d82beSBarry Smith #endif 293