Date: 2024-10-28T09:13:39+00:00

Actual source code: lmesetup.c
slepc-3.22.1 2024-10-28
Report Typos and Errors

      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */
     10: /*
     11:    LME routines related to problem setup
     12: */

     14: #include <slepc/private/lmeimpl.h>

     16: static inline PetscErrorCode LMESetUp_Lyapunov(LME lme)
     17: {
     18:   Mat            C1,C2,X1,X2;
     19:   Vec            dc,dx;

     21:   PetscFunctionBegin;
     22:   PetscCall(MatLRCGetMats(lme->C,NULL,&C1,&dc,&C2));
     23:   PetscCheck(C1==C2,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONGSTATE,"Lyapunov matrix equation requires symmetric right-hand side C");
     24:   PetscCheck(!dc,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONGSTATE,"Lyapunov solvers currently require positive-definite right-hand side C");
     25:   if (lme->X) {
     26:     PetscCall(MatLRCGetMats(lme->X,NULL,&X1,&dx,&X2));
     27:     PetscCheck(X1==X2,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONGSTATE,"Lyapunov matrix equation requires symmetric solution X");
     28:     PetscCheck(!dx,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONGSTATE,"Lyapunov solvers currently assume a positive-definite solution X");
     29:   }
     30:   PetscFunctionReturn(PETSC_SUCCESS);
     31: }

     33: /*@
     34:    LMESetUp - Sets up all the internal data structures necessary for the
     35:    execution of the linear matrix equation solver.

     37:    Collective

     39:    Input Parameter:
     40: .  lme   - linear matrix equation solver context

     42:    Notes:
     43:    This function need not be called explicitly in most cases, since LMESolve()
     44:    calls it. It can be useful when one wants to measure the set-up time
     45:    separately from the solve time.

     47:    Level: developer

     49: .seealso: LMECreate(), LMESolve(), LMEDestroy()
     50: @*/
     51: PetscErrorCode LMESetUp(LME lme)
     52: {
     53:   PetscInt       N;

     55:   PetscFunctionBegin;

     58:   /* reset the convergence flag from the previous solves */
     59:   lme->reason = LME_CONVERGED_ITERATING;

     61:   if (lme->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
     62:   PetscCall(PetscLogEventBegin(LME_SetUp,lme,0,0,0));

     64:   /* Set default solver type (LMESetFromOptions was not called) */
     65:   if (!((PetscObject)lme)->type_name) PetscCall(LMESetType(lme,LMEKRYLOV));

     67:   /* Check problem dimensions */
     68:   PetscCheck(lme->A,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONGSTATE,"LMESetCoefficients must be called first");
     69:   PetscCall(MatGetSize(lme->A,&N,NULL));
     70:   if (lme->ncv > N) lme->ncv = N;

     72:   /* setup options for the particular equation type */
     73:   switch (lme->problem_type) {
     74:     case LME_LYAPUNOV:
     75:       PetscCall(LMESetUp_Lyapunov(lme));
     76:       break;
     77:     case LME_SYLVESTER:
     78:       LMECheckCoeff(lme,lme->B,"B","Sylvester");
     79:       break;
     80:     case LME_GEN_LYAPUNOV:
     81:       LMECheckCoeff(lme,lme->D,"D","Generalized Lyapunov");
     82:       break;
     83:     case LME_GEN_SYLVESTER:
     84:       LMECheckCoeff(lme,lme->B,"B","Generalized Sylvester");
     85:       LMECheckCoeff(lme,lme->D,"D","Generalized Sylvester");
     86:       LMECheckCoeff(lme,lme->E,"E","Generalized Sylvester");
     87:       break;
     88:     case LME_DT_LYAPUNOV:
     89:       break;
     90:     case LME_STEIN:
     91:       LMECheckCoeff(lme,lme->D,"D","Stein");
     92:       break;
     93:   }
     94:   PetscCheck(lme->problem_type==LME_LYAPUNOV,PetscObjectComm((PetscObject)lme),PETSC_ERR_SUP,"There is no solver yet for this matrix equation type");

     96:   /* call specific solver setup */
     97:   PetscUseTypeMethod(lme,setup);

     99:   /* set tolerance if not yet set */
    100:   if (lme->tol==(PetscReal)PETSC_DETERMINE) lme->tol = SLEPC_DEFAULT_TOL;

    102:   PetscCall(PetscLogEventEnd(LME_SetUp,lme,0,0,0));
    103:   lme->setupcalled = 1;
    104:   PetscFunctionReturn(PETSC_SUCCESS);
    105: }

    107: static inline PetscErrorCode LMESetCoefficients_Private(LME lme,Mat A,Mat *lmeA)
    108: {
    109:   PetscInt       m,n;

    111:   PetscFunctionBegin;
    112:   PetscCall(MatGetSize(A,&m,&n));
    113:   PetscCheck(m==n,PetscObjectComm((PetscObject)lme),PETSC_ERR_ARG_WRONG,"Matrix is non-square");
    114:   if (!lme->setupcalled) PetscCall(MatDestroy(lmeA));
    115:   PetscCall(PetscObjectReference((PetscObject)A));
    116:   *lmeA = A;
    117:   PetscFunctionReturn(PETSC_SUCCESS);
    118: }

    120: /*@
    121:    LMESetCoefficients - Sets the coefficient matrices that define the linear matrix
    122:    equation to be solved.

    124:    Collective

    126:    Input Parameters:
    127: +  lme - the matrix function context
    128: .  A   - first coefficient matrix
    129: .  B   - second coefficient matrix
    130: .  D   - third coefficient matrix
    131: -  E   - fourth coefficient matrix

    133:    Notes:
    134:    The matrix equation takes the general form A*X*E+D*X*B=C, where matrix C is not
    135:    provided here but with LMESetRHS(). Not all four matrices must be passed, some
    136:    can be NULL instead, see LMESetProblemType() for details.

    138:    It must be called before LMESetUp(). If it is called again after LMESetUp() then
    139:    the LME object is reset.

    141:    In order to delete a previously set matrix, pass a NULL in the corresponding
    142:    argument.

    144:    Level: beginner

    146: .seealso: LMESolve(), LMESetUp(), LMESetRHS(), LMESetProblemType()
    147: @*/
    148: PetscErrorCode LMESetCoefficients(LME lme,Mat A,Mat B,Mat D,Mat E)
    149: {
    150:   PetscFunctionBegin;
    153:   PetscCheckSameComm(lme,1,A,2);
    154:   if (B) {
    156:     PetscCheckSameComm(lme,1,B,3);
    157:   }
    158:   if (D) {
    160:     PetscCheckSameComm(lme,1,D,4);
    161:   }
    162:   if (E) {
    164:     PetscCheckSameComm(lme,1,E,5);
    165:   }

    167:   if (lme->setupcalled) PetscCall(LMEReset(lme));

    169:   PetscCall(LMESetCoefficients_Private(lme,A,&lme->A));
    170:   if (B) PetscCall(LMESetCoefficients_Private(lme,B,&lme->B));
    171:   else if (!lme->setupcalled) PetscCall(MatDestroy(&lme->B));
    172:   if (D) PetscCall(LMESetCoefficients_Private(lme,D,&lme->D));
    173:   else if (!lme->setupcalled) PetscCall(MatDestroy(&lme->D));
    174:   if (E) PetscCall(LMESetCoefficients_Private(lme,E,&lme->E));
    175:   else if (!lme->setupcalled) PetscCall(MatDestroy(&lme->E));

    177:   lme->setupcalled = 0;
    178:   PetscFunctionReturn(PETSC_SUCCESS);
    179: }

    181: /*@
    182:    LMEGetCoefficients - Gets the coefficient matrices of the matrix equation.

    184:    Not Collective

    186:    Input Parameter:
    187: .  lme - the LME context

    189:    Output Parameters:
    190: +  A   - first coefficient matrix
    191: .  B   - second coefficient matrix
    192: .  D   - third coefficient matrix
    193: -  E   - fourth coefficient matrix

    195:    Level: intermediate

    197: .seealso: LMESolve(), LMESetCoefficients()
    198: @*/
    199: PetscErrorCode LMEGetCoefficients(LME lme,Mat *A,Mat *B,Mat *D,Mat *E)
    200: {
    201:   PetscFunctionBegin;
    203:   if (A) *A = lme->A;
    204:   if (B) *B = lme->B;
    205:   if (D) *D = lme->D;
    206:   if (E) *E = lme->E;
    207:   PetscFunctionReturn(PETSC_SUCCESS);
    208: }

    210: /*@
    211:    LMESetRHS - Sets the right-hand side of the matrix equation, as a low-rank
    212:    matrix.

    214:    Collective

    216:    Input Parameters:
    217: +  lme - the matrix function context
    218: -  C   - the right-hand side matrix

    220:    Notes:
    221:    The matrix equation takes the general form A*X*E+D*X*B=C, where matrix C is
    222:    given with this function. C must be a low-rank matrix of type MATLRC, that is,
    223:    C = U*D*V' where D is diagonal of order k, and U, V are dense tall-skinny
    224:    matrices with k columns. No sparse matrix must be provided when creating the
    225:    MATLRC matrix.

    227:    In equation types that require C to be symmetric, such as Lyapunov, C must be
    228:    created with V=U (or V=NULL).

    230:    Level: beginner

    232: .seealso: LMESetSolution(), LMESetProblemType()
    233: @*/
    234: PetscErrorCode LMESetRHS(LME lme,Mat C)
    235: {
    236:   Mat            A;

    238:   PetscFunctionBegin;
    241:   PetscCheckSameComm(lme,1,C,2);
    242:   PetscCheckTypeName(C,MATLRC);

    244:   PetscCall(MatLRCGetMats(C,&A,NULL,NULL,NULL));
    245:   PetscCheck(!A,PetscObjectComm((PetscObject)C),PETSC_ERR_SUP,"The MatLRC must not have a sparse matrix term");

    247:   PetscCall(PetscObjectReference((PetscObject)C));
    248:   PetscCall(MatDestroy(&lme->C));
    249:   lme->C = C;
    250:   PetscFunctionReturn(PETSC_SUCCESS);
    251: }

    253: /*@
    254:    LMEGetRHS - Gets the right-hand side of the matrix equation.

    256:    Not Collective

    258:    Input Parameter:
    259: .  lme - the LME context

    261:    Output Parameters:
    262: .  C   - the low-rank matrix

    264:    Level: intermediate

    266: .seealso: LMESolve(), LMESetRHS()
    267: @*/
    268: PetscErrorCode LMEGetRHS(LME lme,Mat *C)
    269: {
    270:   PetscFunctionBegin;
    272:   PetscAssertPointer(C,2);
    273:   *C = lme->C;
    274:   PetscFunctionReturn(PETSC_SUCCESS);
    275: }

    277: /*@
    278:    LMESetSolution - Sets the placeholder for the solution of the matrix
    279:    equation, as a low-rank matrix.

    281:    Collective

    283:    Input Parameters:
    284: +  lme - the matrix function context
    285: -  X   - the solution matrix

    287:    Notes:
    288:    The matrix equation takes the general form A*X*E+D*X*B=C, where the solution
    289:    matrix is of low rank and is written in factored form X = U*D*V'. This function
    290:    provides a Mat object of type MATLRC that stores U, V and (optionally) D.
    291:    These factors will be computed during LMESolve().

    293:    In equation types whose solution X is symmetric, such as Lyapunov, X must be
    294:    created with V=U (or V=NULL).

    296:    If the user provides X with this function, then the solver will
    297:    return a solution with rank at most the number of columns of U. Alternatively,
    298:    it is possible to let the solver choose the rank of the solution, by
    299:    setting X to NULL and then calling LMEGetSolution() after LMESolve().

    301:    Level: intermediate

    303: .seealso: LMEGetSolution(), LMESetRHS(), LMESetProblemType(), LMESolve()
    304: @*/
    305: PetscErrorCode LMESetSolution(LME lme,Mat X)
    306: {
    307:   Mat            A;

    309:   PetscFunctionBegin;
    311:   if (X) {
    313:     PetscCheckSameComm(lme,1,X,2);
    314:     PetscCheckTypeName(X,MATLRC);
    315:     PetscCall(MatLRCGetMats(X,&A,NULL,NULL,NULL));
    316:     PetscCheck(!A,PetscObjectComm((PetscObject)X),PETSC_ERR_SUP,"The MatLRC must not have a sparse matrix term");
    317:     PetscCall(PetscObjectReference((PetscObject)X));
    318:   }
    319:   PetscCall(MatDestroy(&lme->X));
    320:   lme->X = X;
    321:   PetscFunctionReturn(PETSC_SUCCESS);
    322: }

    324: /*@
    325:    LMEGetSolution - Gets the solution of the matrix equation.

    327:    Not Collective

    329:    Input Parameter:
    330: .  lme - the LME context

    332:    Output Parameters:
    333: .  X   - the low-rank matrix

    335:    Level: intermediate

    337: .seealso: LMESolve(), LMESetSolution()
    338: @*/
    339: PetscErrorCode LMEGetSolution(LME lme,Mat *X)
    340: {
    341:   PetscFunctionBegin;
    343:   PetscAssertPointer(X,2);
    344:   *X = lme->X;
    345:   PetscFunctionReturn(PETSC_SUCCESS);
    346: }

    348: /*@
    349:    LMEAllocateSolution - Allocate memory storage for common variables such
    350:    as the basis vectors.

    352:    Collective

    354:    Input Parameters:
    355: +  lme   - linear matrix equation solver context
    356: -  extra - number of additional positions, used for methods that require a
    357:            working basis slightly larger than ncv

    359:    Developer Notes:
    360:    This is SLEPC_EXTERN because it may be required by user plugin LME
    361:    implementations.

    363:    Level: developer

    365: .seealso: LMESetUp()
    366: @*/
    367: PetscErrorCode LMEAllocateSolution(LME lme,PetscInt extra)
    368: {
    369:   PetscInt       oldsize,requested;
    370:   Vec            t;

    372:   PetscFunctionBegin;
    373:   requested = lme->ncv + extra;

    375:   /* oldsize is zero if this is the first time setup is called */
    376:   PetscCall(BVGetSizes(lme->V,NULL,NULL,&oldsize));

    378:   /* allocate basis vectors */
    379:   if (!lme->V) PetscCall(LMEGetBV(lme,&lme->V));
    380:   if (!oldsize) {
    381:     if (!((PetscObject)lme->V)->type_name) PetscCall(BVSetType(lme->V,BVMAT));
    382:     PetscCall(MatCreateVecsEmpty(lme->A,&t,NULL));
    383:     PetscCall(BVSetSizesFromVec(lme->V,t,requested));
    384:     PetscCall(VecDestroy(&t));
    385:   } else PetscCall(BVResize(lme->V,requested,PETSC_FALSE));
    386:   PetscFunctionReturn(PETSC_SUCCESS);
    387: }