Date: 2026-01-20T11:35:09+00:00

Actual source code: epsimpl.h

      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: */

     11: #pragma once

     13: #include <slepceps.h>
     14: #include <slepc/private/bvimpl.h>

     16: /* SUBMANSEC = EPS */

     18: SLEPC_EXTERN PetscBool EPSRegisterAllCalled;
     19: SLEPC_EXTERN PetscBool EPSMonitorRegisterAllCalled;
     20: SLEPC_EXTERN PetscErrorCode EPSRegisterAll(void);
     21: SLEPC_EXTERN PetscErrorCode EPSMonitorRegisterAll(void);
     22: SLEPC_EXTERN PetscLogEvent EPS_SetUp,EPS_Solve,EPS_CISS_SVD;

     24: typedef struct _EPSOps *EPSOps;

     26: struct _EPSOps {
     27:   PetscErrorCode (*solve)(EPS);
     28:   PetscErrorCode (*setup)(EPS);
     29:   PetscErrorCode (*setupsort)(EPS);
     30:   PetscErrorCode (*setfromoptions)(EPS,PetscOptionItems);
     31:   PetscErrorCode (*publishoptions)(EPS);
     32:   PetscErrorCode (*destroy)(EPS);
     33:   PetscErrorCode (*reset)(EPS);
     34:   PetscErrorCode (*view)(EPS,PetscViewer);
     35:   PetscErrorCode (*backtransform)(EPS);
     36:   PetscErrorCode (*computevectors)(EPS);
     37:   PetscErrorCode (*setdefaultst)(EPS);
     38:   PetscErrorCode (*setdstype)(EPS);
     39: };

     41: /*
     42:    Maximum number of monitors you can run with a single EPS
     43: */
     44: #define MAXEPSMONITORS 5

     46: /*
     47:    The solution process goes through several states
     48: */
     49: typedef enum { EPS_STATE_INITIAL,
     50:                EPS_STATE_SETUP,
     51:                EPS_STATE_SOLVED,
     52:                EPS_STATE_EIGENVECTORS } EPSStateType;

     54: /*
     55:    To classify the different solvers into categories
     56: */
     57: typedef enum { EPS_CATEGORY_KRYLOV,      /* Krylov solver: relies on STApply and STBackTransform (same as OTHER) */
     58:                EPS_CATEGORY_PRECOND,     /* Preconditioned solver: uses ST only to manage preconditioner */
     59:                EPS_CATEGORY_CONTOUR,     /* Contour integral: ST used to solve linear systems at integration points */
     60:                EPS_CATEGORY_OTHER } EPSSolverType;

     62: /*
     63:    To check for unsupported features at EPSSetUp_XXX()
     64: */
     65: typedef enum { EPS_FEATURE_BALANCE=1,       /* balancing */
     66:                EPS_FEATURE_ARBITRARY=2,     /* arbitrary selection of eigepairs */
     67:                EPS_FEATURE_REGION=4,        /* nontrivial region for filtering */
     68:                EPS_FEATURE_EXTRACTION=8,    /* extraction technique different from Ritz */
     69:                EPS_FEATURE_CONVERGENCE=16,  /* convergence test selected by user */
     70:                EPS_FEATURE_STOPPING=32,     /* stopping test */
     71:                EPS_FEATURE_THRESHOLD=64,    /* threshold stopping test */
     72:                EPS_FEATURE_TWOSIDED=128     /* two-sided variant */
     73:              } EPSFeatureType;

     75: /*
     76:    Defines the EPS data structure
     77: */
     78: struct _p_EPS {
     79:   PETSCHEADER(struct _EPSOps);
     80:   /*------------------------- User parameters ---------------------------*/
     81:   PetscInt       max_it;           /* maximum number of iterations */
     82:   PetscInt       nev;              /* number of eigenvalues to compute */
     83:   PetscInt       ncv;              /* number of basis vectors */
     84:   PetscInt       mpd;              /* maximum dimension of projected problem */
     85:   PetscInt       nini,ninil;       /* number of initial vectors (negative means not copied yet) */
     86:   PetscInt       nds;              /* number of basis vectors of deflation space */
     87:   PetscScalar    target;           /* target value */
     88:   PetscReal      tol;              /* tolerance */
     89:   PetscReal      thres;            /* threshold */
     90:   PetscBool      threlative;       /* threshold is relative */
     91:   EPSConv        conv;             /* convergence test */
     92:   EPSStop        stop;             /* stopping test */
     93:   EPSWhich       which;            /* which part of the spectrum to be sought */
     94:   PetscReal      inta,intb;        /* interval [a,b] for spectrum slicing */
     95:   EPSProblemType problem_type;     /* which kind of problem to be solved */
     96:   EPSExtraction  extraction;       /* which kind of extraction to be applied */
     97:   EPSBalance     balance;          /* the balancing method */
     98:   PetscInt       balance_its;      /* number of iterations of the balancing method */
     99:   PetscReal      balance_cutoff;   /* cutoff value for balancing */
    100:   PetscBool      trueres;          /* whether the true residual norm must be computed */
    101:   PetscBool      trackall;         /* whether all the residuals must be computed */
    102:   PetscBool      purify;           /* whether eigenvectors need to be purified */
    103:   PetscBool      twosided;         /* whether to compute left eigenvectors (two-sided solver) */

    105:   /*-------------- User-provided functions and contexts -----------------*/
    106:   EPSConvergenceTestFn      *converged;
    107:   EPSConvergenceTestFn      *convergeduser;
    108:   PetscCtxDestroyFn         *convergeddestroy;
    109:   EPSStoppingTestFn         *stopping;
    110:   EPSStoppingTestFn         *stoppinguser;
    111:   PetscCtxDestroyFn         *stoppingdestroy;
    112:   SlepcArbitrarySelectionFn *arbitrary;
    113:   void                      *convergedctx;
    114:   void                      *stoppingctx;
    115:   void                      *arbitraryctx;
    116:   EPSMonitorFn              *monitor[MAXEPSMONITORS];
    117:   PetscCtxDestroyFn         *monitordestroy[MAXEPSMONITORS];
    118:   void                      *monitorcontext[MAXEPSMONITORS];
    119:   PetscInt                  numbermonitors;

    121:   /*----------------- Child objects and working data -------------------*/
    122:   ST             st;               /* spectral transformation object */
    123:   DS             ds;               /* direct solver object */
    124:   BV             V;                /* set of basis vectors and computed eigenvectors */
    125:   BV             W;                /* left basis vectors (if left eigenvectors requested) */
    126:   RG             rg;               /* optional region for filtering */
    127:   SlepcSC        sc;               /* sorting criterion data */
    128:   Vec            D;                /* diagonal matrix for balancing */
    129:   Vec            *IS,*ISL;         /* references to user-provided initial spaces */
    130:   Vec            *defl;            /* references to user-provided deflation space */
    131:   PetscScalar    *eigr,*eigi;      /* real and imaginary parts of eigenvalues */
    132:   PetscReal      *errest;          /* error estimates */
    133:   PetscScalar    *rr,*ri;          /* values computed by user's arbitrary selection function */
    134:   PetscInt       *perm;            /* permutation for eigenvalue ordering */
    135:   PetscInt       nwork;            /* number of work vectors */
    136:   Vec            *work;            /* work vectors */
    137:   void           *data;            /* placeholder for solver-specific stuff */

    139:   /* ----------------------- Status variables --------------------------*/
    140:   EPSStateType   state;            /* initial -> setup -> solved -> eigenvectors */
    141:   EPSSolverType  categ;            /* solver category */
    142:   PetscInt       nconv;            /* number of converged eigenvalues */
    143:   PetscInt       its;              /* number of iterations so far computed */
    144:   PetscInt       n,nloc;           /* problem dimensions (global, local) */
    145:   PetscReal      nrma,nrmb;        /* computed matrix norms */
    146:   PetscBool      useds;            /* whether the solver uses the DS object or not */
    147:   PetscBool      isgeneralized;
    148:   PetscBool      ispositive;
    149:   PetscBool      ishermitian;
    150:   PetscBool      isstructured;
    151:   EPSConvergedReason reason;
    152: };

    154: /*
    155:     Macros to test valid EPS arguments
    156: */
    157: #if !defined(PETSC_USE_DEBUG)

    159: #define EPSCheckSolved(h,arg) do {(void)(h);} while (0)

    161: #else

    163: #define EPSCheckSolved(h,arg) \
    164:   do { \
    165:     PetscCheck((h)->state>=EPS_STATE_SOLVED,PetscObjectComm((PetscObject)(h)),PETSC_ERR_ARG_WRONGSTATE,"Must call EPSSolve() first: Parameter #%d",arg); \
    166:   } while (0)

    168: #endif

    170: /*
    171:     Macros to check settings at EPSSetUp()
    172: */

    174: /* EPSCheckHermitianDefinite: the problem is HEP or GHEP */
    175: #define EPSCheckHermitianDefiniteCondition(eps,condition,msg) \
    176:   do { \
    177:     if (condition) { \
    178:       PetscCheck((eps)->ishermitian,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s cannot be used for non-%s problems",((PetscObject)(eps))->type_name,(msg),SLEPC_STRING_HERMITIAN); \
    179:       PetscCheck(!(eps)->isgeneralized || (eps)->ispositive,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s requires that the problem is %s-definite",((PetscObject)(eps))->type_name,(msg),SLEPC_STRING_HERMITIAN); \
    180:     } \
    181:   } while (0)
    182: #define EPSCheckHermitianDefinite(eps) EPSCheckHermitianDefiniteCondition(eps,PETSC_TRUE,"")

    184: /* EPSCheckHermitian: the problem is HEP, GHEP, or GHIEP */
    185: #define EPSCheckHermitianCondition(eps,condition,msg) \
    186:   do { \
    187:     if (condition) { \
    188:       PetscCheck((eps)->ishermitian,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s cannot be used for non-%s problems",((PetscObject)(eps))->type_name,(msg),SLEPC_STRING_HERMITIAN); \
    189:     } \
    190:   } while (0)
    191: #define EPSCheckHermitian(eps) EPSCheckHermitianCondition(eps,PETSC_TRUE,"")

    193: /* EPSCheckDefinite: the problem is not GHIEP */
    194: #define EPSCheckDefiniteCondition(eps,condition,msg) \
    195:   do { \
    196:     if (condition) { \
    197:       PetscCheck(!(eps)->isgeneralized || !(eps)->ishermitian || (eps)->ispositive,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s cannot be used for %s-indefinite problems",((PetscObject)(eps))->type_name,(msg),SLEPC_STRING_HERMITIAN); \
    198:     } \
    199:   } while (0)
    200: #define EPSCheckDefinite(eps) EPSCheckDefiniteCondition(eps,PETSC_TRUE,"")

    202: /* EPSCheckStandard: the problem is HEP or NHEP */
    203: #define EPSCheckStandardCondition(eps,condition,msg) \
    204:   do { \
    205:     if (condition) { \
    206:       PetscCheck(!(eps)->isgeneralized,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s cannot be used for generalized problems",((PetscObject)(eps))->type_name,(msg)); \
    207:     } \
    208:   } while (0)
    209: #define EPSCheckStandard(eps) EPSCheckStandardCondition(eps,PETSC_TRUE,"")

    211: /* EPSCheckNotStructured: the problem is not structured */
    212: #define EPSCheckNotStructuredCondition(eps,condition,msg) \
    213:   do { \
    214:     if (condition) { \
    215:       PetscCheck(!(eps)->isstructured,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s does not provide support for structured eigenproblems",((PetscObject)(eps))->type_name,(msg)); \
    216:     } \
    217:   } while (0)
    218: #define EPSCheckNotStructured(eps) EPSCheckNotStructuredCondition(eps,PETSC_TRUE,"")

    220: /* EPSCheckSinvert: shift-and-invert ST */
    221: #define EPSCheckSinvertCondition(eps,condition,msg) \
    222:   do { \
    223:     if (condition) { \
    224:       PetscBool __flg; \
    225:       PetscCall(PetscObjectTypeCompare((PetscObject)(eps)->st,STSINVERT,&__flg)); \
    226:       PetscCheck(__flg,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s requires a shift-and-invert spectral transform",((PetscObject)(eps))->type_name,(msg)); \
    227:     } \
    228:   } while (0)
    229: #define EPSCheckSinvert(eps) EPSCheckSinvertCondition(eps,PETSC_TRUE,"")

    231: /* EPSCheckSinvertCayley: shift-and-invert or Cayley ST */
    232: #define EPSCheckSinvertCayleyCondition(eps,condition,msg) \
    233:   do { \
    234:     if (condition) { \
    235:       PetscBool __flg; \
    236:       PetscCall(PetscObjectTypeCompareAny((PetscObject)(eps)->st,&__flg,STSINVERT,STCAYLEY,"")); \
    237:       PetscCheck(__flg,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s requires shift-and-invert or Cayley transform",((PetscObject)(eps))->type_name,(msg)); \
    238:     } \
    239:   } while (0)
    240: #define EPSCheckSinvertCayley(eps) EPSCheckSinvertCayleyCondition(eps,PETSC_TRUE,"")

    242: /* Check for unsupported features */
    243: #define EPSCheckUnsupportedCondition(eps,mask,condition,msg) \
    244:   do { \
    245:     if (condition) { \
    246:       PetscCheck(!((mask) & EPS_FEATURE_BALANCE) || (eps)->balance==EPS_BALANCE_NONE,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s does not support balancing",((PetscObject)(eps))->type_name,(msg)); \
    247:       PetscCheck(!((mask) & EPS_FEATURE_ARBITRARY) || !(eps)->arbitrary,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s does not support arbitrary selection of eigenpairs",((PetscObject)(eps))->type_name,(msg)); \
    248:       if ((mask) & EPS_FEATURE_REGION) { \
    249:         PetscBool      __istrivial; \
    250:         PetscCall(RGIsTrivial((eps)->rg,&__istrivial)); \
    251:         PetscCheck(__istrivial,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s does not support region filtering",((PetscObject)(eps))->type_name,(msg)); \
    252:       } \
    253:       PetscCheck(!((mask) & EPS_FEATURE_EXTRACTION) || (eps)->extraction==EPS_RITZ,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s only supports Ritz extraction",((PetscObject)(eps))->type_name,(msg)); \
    254:       PetscCheck(!((mask) & EPS_FEATURE_CONVERGENCE) || (eps)->converged==EPSConvergedRelative,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s only supports the default convergence test",((PetscObject)(eps))->type_name,(msg)); \
    255:       PetscCheck(!((mask) & EPS_FEATURE_STOPPING) || (eps)->stopping==EPSStoppingBasic,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s only supports the default stopping test",((PetscObject)(eps))->type_name,(msg)); \
    256:       PetscCheck(!((mask) & EPS_FEATURE_THRESHOLD) || (eps)->stopping!=EPSStoppingThreshold,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s does not support the threshold stopping test",((PetscObject)(eps))->type_name,(msg)); \
    257:       PetscCheck(!((mask) & EPS_FEATURE_TWOSIDED) || !(eps)->twosided,PetscObjectComm((PetscObject)(eps)),PETSC_ERR_SUP,"The solver '%s'%s cannot compute left eigenvectors (no two-sided variant)",((PetscObject)(eps))->type_name,(msg)); \
    258:     } \
    259:   } while (0)
    260: #define EPSCheckUnsupported(eps,mask) EPSCheckUnsupportedCondition(eps,mask,PETSC_TRUE,"")

    262: /* Check for ignored features */
    263: #define EPSCheckIgnoredCondition(eps,mask,condition,msg) \
    264:   do { \
    265:     if (condition) { \
    266:       if (((mask) & EPS_FEATURE_BALANCE) && (eps)->balance!=EPS_BALANCE_NONE) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the balancing settings\n",((PetscObject)(eps))->type_name,(msg))); \
    267:       if (((mask) & EPS_FEATURE_ARBITRARY) && (eps)->arbitrary) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the settings for arbitrary selection of eigenpairs\n",((PetscObject)(eps))->type_name,(msg))); \
    268:       if ((mask) & EPS_FEATURE_REGION) { \
    269:         PetscBool __istrivial; \
    270:         PetscCall(RGIsTrivial((eps)->rg,&__istrivial)); \
    271:         if (!__istrivial) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the specified region\n",((PetscObject)(eps))->type_name,(msg))); \
    272:       } \
    273:       if (((mask) & EPS_FEATURE_EXTRACTION) && (eps)->extraction!=EPS_RITZ) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the extraction settings\n",((PetscObject)(eps))->type_name,(msg))); \
    274:       if (((mask) & EPS_FEATURE_CONVERGENCE) && (eps)->converged!=EPSConvergedRelative) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the convergence test settings\n",((PetscObject)(eps))->type_name,(msg))); \
    275:       if (((mask) & EPS_FEATURE_STOPPING) && (eps)->stopping!=EPSStoppingBasic) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the stopping test settings\n",((PetscObject)(eps))->type_name,(msg))); \
    276:       if (((mask) & EPS_FEATURE_TWOSIDED) && (eps)->twosided) PetscCall(PetscInfo((eps),"The solver '%s'%s ignores the two-sided flag\n",((PetscObject)(eps))->type_name,(msg))); \
    277:     } \
    278:   } while (0)
    279: #define EPSCheckIgnored(eps,mask) EPSCheckIgnoredCondition(eps,mask,PETSC_TRUE,"")

    281: /*
    282:     EPSSetCtxThreshold - Fills EPSStoppingCtx with data needed for the threshold stopping test
    283: */
    284: #define EPSSetCtxThreshold(eps,eigr,eigi,k) \
    285:   do { \
    286:     if (eps->stop==EPS_STOP_THRESHOLD && k) { \
    287:       PetscScalar __kr=eigr[k-1],__ki=eigi[k-1],__kr0=eigr[0],__ki0=eigi[0]; \
    288:       PetscCall(STBackTransform(eps->st,1,&__kr,&__ki)); \
    289:       PetscCall(STBackTransform(eps->st,1,&__kr0,&__ki0)); \
    290:       if (eps->which==EPS_LARGEST_MAGNITUDE || eps->which==EPS_SMALLEST_MAGNITUDE) { \
    291:         ((EPSStoppingCtx)eps->stoppingctx)->firstev = SlepcAbsEigenvalue(__kr0,__ki0); \
    292:         ((EPSStoppingCtx)eps->stoppingctx)->lastev  = SlepcAbsEigenvalue(__kr,__ki); \
    293:       } else { \
    294:         ((EPSStoppingCtx)eps->stoppingctx)->firstev = PetscRealPart(__kr0); \
    295:         ((EPSStoppingCtx)eps->stoppingctx)->lastev  = PetscRealPart(__kr); \
    296:       } \
    297:     } \
    298:   } while (0)

    300: /*
    301:   EPS_SetInnerProduct - set B matrix for inner product if appropriate.
    302: */
    303: static inline PetscErrorCode EPS_SetInnerProduct(EPS eps)
    304: {
    305:   Mat            B;

    307:   PetscFunctionBegin;
    308:   if (!eps->V) PetscCall(EPSGetBV(eps,&eps->V));
    309:   if (eps->ispositive || (eps->isgeneralized && eps->ishermitian)) {
    310:     PetscCall(STGetBilinearForm(eps->st,&B));
    311:     PetscCall(BVSetMatrix(eps->V,B,PetscNot(eps->ispositive)));
    312:     if (eps->twosided) PetscCall(BVSetMatrix(eps->W,B,PetscNot(eps->ispositive)));
    313:     PetscCall(MatDestroy(&B));
    314:   } else PetscCall(BVSetMatrix(eps->V,NULL,PETSC_FALSE));
    315:   PetscFunctionReturn(PETSC_SUCCESS);
    316: }

    318: /*
    319:   EPS_Purify - purify the first k vectors in the V basis
    320: */
    321: static inline PetscErrorCode EPS_Purify(EPS eps,PetscInt k)
    322: {
    323:   PetscInt       i;
    324:   Vec            v,z;

    326:   PetscFunctionBegin;
    327:   PetscCall(BVCreateVec(eps->V,&v));
    328:   for (i=0;i<k;i++) {
    329:     PetscCall(BVCopyVec(eps->V,i,v));
    330:     PetscCall(BVGetColumn(eps->V,i,&z));
    331:     PetscCall(STApply(eps->st,v,z));
    332:     PetscCall(BVRestoreColumn(eps->V,i,&z));
    333:   }
    334:   PetscCall(VecDestroy(&v));
    335:   PetscFunctionReturn(PETSC_SUCCESS);
    336: }

    338: /*
    339:   EPS_KSPSetOperators - Sets the KSP matrices, see also ST_KSPSetOperators()
    340: */
    341: static inline PetscErrorCode EPS_KSPSetOperators(KSP ksp,Mat A,Mat B)
    342: {
    343:   const char     *prefix;

    345:   PetscFunctionBegin;
    346:   PetscCall(KSPSetOperators(ksp,A,B));
    347:   PetscCall(MatGetOptionsPrefix(B,&prefix));
    348:   if (!prefix) {
    349:     /* set Mat prefix to be the same as KSP to enable setting command-line options (e.g. MUMPS)
    350:        only applies if the Mat has no user-defined prefix */
    351:     PetscCall(KSPGetOptionsPrefix(ksp,&prefix));
    352:     PetscCall(MatSetOptionsPrefix(B,prefix));
    353:   }
    354:   PetscFunctionReturn(PETSC_SUCCESS);
    355: }

    357: /*
    358:   EPS_GetActualConverged - Gets the actual value of nconv; in special cases the
    359:   number of available eigenvalues is larger than the computed ones
    360: */
    361: static inline PetscErrorCode EPS_GetActualConverged(EPS eps,PetscInt *nconv)
    362: {
    363:   PetscFunctionBegin;
    364:   *nconv = eps->nconv;
    365:   if (eps->isstructured) {
    366:     if (eps->problem_type == EPS_BSE && (eps->which == EPS_SMALLEST_MAGNITUDE || eps->which == EPS_LARGEST_MAGNITUDE || eps->which == EPS_TARGET_MAGNITUDE)) *nconv *= 2;
    367:     if (eps->problem_type == EPS_HAMILT && (eps->which == EPS_SMALLEST_MAGNITUDE || eps->which == EPS_LARGEST_MAGNITUDE || eps->which == EPS_TARGET_MAGNITUDE)) *nconv *= 2;
    368:   }
    369:   PetscFunctionReturn(PETSC_SUCCESS);
    370: }

    372: /*
    373:   EPS_GetEigenvector - Gets the i-th eigenvector taking into account the case
    374:   where i exceeds the number of computed vectors (structure-preserving solver).
    375:   The argument V should be eps->V for right eigenvectors, eps->W for left ones.
    376: */
    377: static inline PetscErrorCode EPS_GetEigenvector(EPS eps,BV V,PetscInt i,Vec Vr,Vec Vi)
    378: {
    379:   PetscInt  k;
    380:   Vec       v0,v1,w,w0,w1;
    381:   Mat       H;
    382:   IS        is[2];
    383: #if !defined(PETSC_USE_COMPLEX)
    384:   PetscInt  k0,k1,k2,iquad;
    385:   PetscReal nrm,nrmr=0.0,nrmi=0.0,sgn;
    386: #endif

    388:   PetscFunctionBegin;
    389:   if (!eps->isstructured) {
    390:     k = eps->perm[i];
    391:     PetscCall(BV_GetEigenvector(V,k,eps->eigi[k],Vr,Vi));
    392:   } else {
    393:     if (eps->problem_type == EPS_BSE && (eps->which == EPS_SMALLEST_MAGNITUDE || eps->which == EPS_LARGEST_MAGNITUDE || eps->which == EPS_TARGET_MAGNITUDE)) {
    394:       /* BSE problem, even index is +lambda, odd index is -lambda */
    395:       k = eps->perm[i/2];
    396:       if (i%2) {
    397:         /* eigenvector of -lambda is J*conj(X) where J=[0 I; I 0] and x is eigenvector of lambda */
    398:         PetscCall(VecDuplicate(Vr?Vr:Vi,&w));
    399:         PetscCall(STGetMatrix(eps->st,0,&H));
    400:         PetscCall(MatNestGetISs(H,is,NULL));
    401:         if (Vr) {
    402:           PetscCall(BV_GetEigenvector(V,k,eps->eigi[k],w,NULL));
    403:           PetscCall(VecConjugate(w));
    404:           PetscCall(VecGetSubVector(w,is[0],&w0));
    405:           PetscCall(VecGetSubVector(w,is[1],&w1));
    406:           PetscCall(VecGetSubVector(Vr,is[0],&v0));
    407:           PetscCall(VecGetSubVector(Vr,is[1],&v1));
    408:           PetscCall(VecCopy(w1,v0));
    409:           PetscCall(VecCopy(w0,v1));
    410:           PetscCall(VecRestoreSubVector(w,is[0],&w0));
    411:           PetscCall(VecRestoreSubVector(w,is[1],&w1));
    412:           PetscCall(VecRestoreSubVector(Vr,is[0],&v0));
    413:           PetscCall(VecRestoreSubVector(Vr,is[1],&v1));
    414:         }
    415: #if !defined(PETSC_USE_COMPLEX)
    416:         if (Vi) {
    417:           PetscCall(BV_GetEigenvector(V,k,eps->eigi[k],NULL,w));
    418:           PetscCall(VecScale(w,-1.0));
    419:           PetscCall(VecGetSubVector(w,is[0],&w0));
    420:           PetscCall(VecGetSubVector(w,is[1],&w1));
    421:           PetscCall(VecGetSubVector(Vi,is[0],&v0));
    422:           PetscCall(VecGetSubVector(Vi,is[1],&v1));
    423:           PetscCall(VecCopy(w1,v0));
    424:           PetscCall(VecCopy(w0,v1));
    425:           PetscCall(VecRestoreSubVector(w,is[0],&w0));
    426:           PetscCall(VecRestoreSubVector(w,is[1],&w1));
    427:           PetscCall(VecRestoreSubVector(Vi,is[0],&v0));
    428:           PetscCall(VecRestoreSubVector(Vi,is[1],&v1));
    429:         }
    430: #endif
    431:         PetscCall(VecDestroy(&w));
    432:       } else {
    433:         PetscCall(BV_GetEigenvector(V,k,eps->eigi[k],Vr,Vi));
    434:       }
    435:     } else if (eps->problem_type == EPS_HAMILT) {
    436:       k = eps->perm[i/2];
    437: #if !defined(PETSC_USE_COMPLEX)
    438:       if (eps->eigi[k]==0.0) { /* real eigenvalue */
    439:         if (Vr) {
    440:           PetscCall(BVCopyVec(V,k+eps->ncv/2+1,Vr));
    441:           PetscCall(BVGetColumn(V,k,&w));
    442:           PetscCall(VecAXPY(Vr,(i%2)?-eps->eigr[k]:eps->eigr[k],w));
    443:           PetscCall(BVRestoreColumn(V,k,&w));
    444:           PetscCall(VecNorm(Vr,NORM_2,&nrmr));
    445:         }
    446:         if (Vi) PetscCall(VecZeroEntries(Vi));
    447:         nrm = nrmr;
    448:       } else if (eps->eigr[k]==0.0 ) { /* purely imaginary eigenvalue */
    449:         if (Vr) {
    450:           PetscCall(BVCopyVec(V,k+eps->ncv/2+1,Vr));
    451:           PetscCall(VecNorm(Vr,NORM_2,&nrmr));
    452:         }
    453:         if (Vi) {
    454:           PetscCall(BVCopyVec(V,k,Vi));
    455:           PetscCall(VecScale(Vi,(i%2)?-eps->eigi[k]:eps->eigi[k]));
    456:           PetscCall(VecNorm(Vi,NORM_2,&nrmi));
    457:         }
    458:         nrm = SlepcAbs(nrmr,nrmi);
    459:       } else { /* quadruple eigenvalue (-conj(lambda),-lambda,lambda,conj(lambda)) */
    460:         iquad = i%2;  /* index within the 4 values */
    461:         if (i>=2) {
    462:           k2 = eps->perm[(i-2)/2];
    463:           if (eps->eigr[k]==eps->eigr[k2] && eps->eigi[k]==-eps->eigi[k2]) iquad += 2;
    464:         }
    465:         k0 = (iquad<2)? k: k2;
    466:         k1 = k0+1;
    467:         /* Vr+Vi*i obtained as eig*u+v where u=ur+ui*i is stored in cols k0 (ur) and k1 (ui) and
    468:            v=vr+vi*i is in cols shifted by ncv/2+1.
    469:            For lambda=eigr+eigi*i:
    470:             Vr+Vi*i = (eigr+eigi*i)(ur+ui*i) + vr+vi*i
    471:             Vr+Vi*i = eigr*(ur+ui*i) - eigi*ui+eigi*ur*i + vr+vi*i
    472:             Vr+Vi*i = eigr*ur-eigi*ui+vr + (eigi*ur+eigr*ui+vi)*i
    473:            For -conj(lambda): eigr, ui and vi have the signs changed
    474:            For       -lambda: eigr and eigi have the signs changed
    475:            For  conj(lambda): eigi, ui and vi have the signs changed   */
    476:         if (Vr) {
    477:           sgn = (iquad<2)? -1.0: 1.0;
    478:           PetscCall(BVCopyVec(V,k0,Vr));                  /* ur */
    479:           PetscCall(VecScale(Vr,sgn*eps->eigr[k0]));
    480:           PetscCall(BVGetColumn(V,k1,&w));                /* ui */
    481:           PetscCall(VecAXPY(Vr,-sgn*eps->eigi[k0],w));
    482:           PetscCall(BVRestoreColumn(V,k1,&w));
    483:           PetscCall(BVGetColumn(V,k0+eps->ncv/2+1,&w));   /* vr */
    484:           PetscCall(VecAXPY(Vr,1.0,w));
    485:           PetscCall(BVRestoreColumn(V,k0+eps->ncv/2+1,&w));
    486:           PetscCall(VecNorm(Vr,NORM_2,&nrmr));
    487:         }
    488:         if (Vi) {
    489:           sgn = (iquad%2)? -1.0: 1.0;
    490:           PetscCall(BVCopyVec(V,k0,Vi));                  /* ur */
    491:           PetscCall(VecScale(Vi,sgn*eps->eigi[k0]));
    492:           PetscCall(BVGetColumn(V,k1,&w));                /* ui */
    493:           PetscCall(VecAXPY(Vi,sgn*eps->eigr[k0],w));
    494:           PetscCall(BVRestoreColumn(V,k1,&w));
    495:           PetscCall(BVGetColumn(V,k1+eps->ncv/2+1,&w));   /* vi */
    496:           sgn = (iquad%3)? 1.0: -1.0;
    497:           PetscCall(VecAXPY(Vi,sgn,w));
    498:           PetscCall(BVRestoreColumn(V,k1+eps->ncv/2+1,&w));
    499:           PetscCall(VecNorm(Vi,NORM_2,&nrmi));
    500:         }
    501:         nrm = SlepcAbs(nrmr,nrmi);
    502:       }
    503:       if (Vr) PetscCall(VecScale(Vr,1.0/nrm));
    504:       if (Vi) PetscCall(VecScale(Vi,1.0/nrm));
    505: #endif
    506:     } else SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_LIB,"Inconsistent state");
    507:   }
    508:   PetscFunctionReturn(PETSC_SUCCESS);
    509: }

    511: SLEPC_INTERN PetscErrorCode EPSSetWhichEigenpairs_Default(EPS);
    512: SLEPC_INTERN PetscErrorCode EPSSetDimensions_Default(EPS,PetscInt*,PetscInt*,PetscInt*);
    513: SLEPC_INTERN PetscErrorCode EPSBackTransform_Default(EPS);
    514: SLEPC_INTERN PetscErrorCode EPSComputeVectors(EPS);
    515: SLEPC_INTERN PetscErrorCode EPSComputeVectors_Hermitian(EPS);
    516: SLEPC_INTERN PetscErrorCode EPSComputeVectors_Schur(EPS);
    517: SLEPC_INTERN PetscErrorCode EPSComputeVectors_Indefinite(EPS);
    518: SLEPC_INTERN PetscErrorCode EPSComputeVectors_Twosided(EPS);
    519: SLEPC_INTERN PetscErrorCode EPSComputeVectors_Slice(EPS);
    520: SLEPC_INTERN PetscErrorCode EPSComputeResidualNorm_Private(EPS,PetscBool,PetscScalar,PetscScalar,Vec,Vec,Vec*,PetscReal*);
    521: SLEPC_INTERN PetscErrorCode EPSComputeRitzVector(EPS,PetscScalar*,PetscScalar*,BV,Vec,Vec);
    522: SLEPC_INTERN PetscErrorCode EPSGetStartVector(EPS,PetscInt,PetscBool*);
    523: SLEPC_INTERN PetscErrorCode EPSGetLeftStartVector(EPS,PetscInt,PetscBool*);
    524: SLEPC_INTERN PetscErrorCode MatEstimateSpectralRange_EPS(Mat,PetscReal*,PetscReal*);

    526: /* Private functions of the solver implementations */

    528: SLEPC_INTERN PetscErrorCode EPSDelayedArnoldi(EPS,PetscScalar*,PetscInt,PetscInt,PetscInt*,PetscReal*,PetscBool*);
    529: SLEPC_INTERN PetscErrorCode EPSDelayedArnoldi1(EPS,PetscScalar*,PetscInt,PetscInt,PetscInt*,PetscReal*,PetscBool*);
    530: SLEPC_INTERN PetscErrorCode EPSKrylovConvergence(EPS,PetscBool,PetscInt,PetscInt,PetscReal,PetscReal,PetscReal,PetscInt*);
    531: SLEPC_INTERN PetscErrorCode EPSPseudoLanczos(EPS,PetscReal*,PetscReal*,PetscReal*,PetscInt,PetscInt*,PetscBool*,PetscBool*,PetscReal*,Vec);
    532: SLEPC_INTERN PetscErrorCode EPSBuildBalance_Krylov(EPS);
    533: SLEPC_INTERN PetscErrorCode EPSSetDefaultST(EPS);
    534: SLEPC_INTERN PetscErrorCode EPSSetDefaultST_Precond(EPS);
    535: SLEPC_INTERN PetscErrorCode EPSSetDefaultST_GMRES(EPS);
    536: SLEPC_INTERN PetscErrorCode EPSSetDefaultST_NoFactor(EPS);
    537: SLEPC_INTERN PetscErrorCode EPSSetUpSort_Basic(EPS);
    538: SLEPC_INTERN PetscErrorCode EPSSetUpSort_Default(EPS);