Date: 2016-07-24T17:15:43+00:00

Actual source code: blmvm.c
petsc-3.7.3 2016-07-24
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      1: #include <petsctaolinesearch.h>
      2: #include <../src/tao/matrix/lmvmmat.h>
      3: #include <../src/tao/unconstrained/impls/lmvm/lmvm.h>
      4: #include <../src/tao/bound/impls/blmvm/blmvm.h>

      6: /*------------------------------------------------------------*/
      9: static PetscErrorCode TaoSolve_BLMVM(Tao tao)
     10: {
     11:   PetscErrorCode               ierr;
     12:   TAO_BLMVM                    *blmP = (TAO_BLMVM *)tao->data;
     13:   TaoConvergedReason           reason = TAO_CONTINUE_ITERATING;
     14:   TaoLineSearchConvergedReason ls_status = TAOLINESEARCH_CONTINUE_ITERATING;
     15:   PetscReal                    f, fold, gdx, gnorm;
     16:   PetscReal                    stepsize = 1.0,delta;

     19:   /*  Project initial point onto bounds */
     20:   TaoComputeVariableBounds(tao);
     21:   VecMedian(tao->XL,tao->solution,tao->XU,tao->solution);
     22:   TaoLineSearchSetVariableBounds(tao->linesearch,tao->XL,tao->XU);

     25:   /* Check convergence criteria */
     26:   TaoComputeObjectiveAndGradient(tao, tao->solution,&f,blmP->unprojected_gradient);
     27:   VecBoundGradientProjection(blmP->unprojected_gradient,tao->solution, tao->XL,tao->XU,tao->gradient);

     29:   TaoGradientNorm(tao, tao->gradient,NORM_2,&gnorm);
     30:   if (PetscIsInfOrNanReal(f) || PetscIsInfOrNanReal(gnorm)) SETERRQ(PETSC_COMM_SELF,1, "User provided compute function generated Inf pr NaN");

     32:   TaoMonitor(tao, tao->niter, f, gnorm, 0.0, stepsize, &reason);
     33:   if (reason != TAO_CONTINUE_ITERATING) return(0);

     35:   /* Set initial scaling for the function */
     36:   if (f != 0.0) {
     37:     delta = 2.0*PetscAbsScalar(f) / (gnorm*gnorm);
     38:   } else {
     39:     delta = 2.0 / (gnorm*gnorm);
     40:   }
     41:   MatLMVMSetDelta(blmP->M,delta);

     43:   /* Set counter for gradient/reset steps */
     44:   blmP->grad = 0;
     45:   blmP->reset = 0;

     47:   /* Have not converged; continue with Newton method */
     48:   while (reason == TAO_CONTINUE_ITERATING) {
     49:     /* Compute direction */
     50:     MatLMVMUpdate(blmP->M, tao->solution, tao->gradient);
     51:     MatLMVMSolve(blmP->M, blmP->unprojected_gradient, tao->stepdirection);
     52:     VecBoundGradientProjection(tao->stepdirection,tao->solution,tao->XL,tao->XU,tao->gradient);

     54:     /* Check for success (descent direction) */
     55:     VecDot(blmP->unprojected_gradient, tao->gradient, &gdx);
     56:     if (gdx <= 0) {
     57:       /* Step is not descent or solve was not successful
     58:          Use steepest descent direction (scaled) */
     59:       ++blmP->grad;

     61:       if (f != 0.0) {
     62:         delta = 2.0*PetscAbsScalar(f) / (gnorm*gnorm);
     63:       } else {
     64:         delta = 2.0 / (gnorm*gnorm);
     65:       }
     66:       MatLMVMSetDelta(blmP->M,delta);
     67:       MatLMVMReset(blmP->M);
     68:       MatLMVMUpdate(blmP->M, tao->solution, blmP->unprojected_gradient);
     69:       MatLMVMSolve(blmP->M,blmP->unprojected_gradient, tao->stepdirection);
     70:     }
     71:     VecScale(tao->stepdirection,-1.0);

     73:     /* Perform the linesearch */
     74:     fold = f;
     75:     VecCopy(tao->solution, blmP->Xold);
     76:     VecCopy(blmP->unprojected_gradient, blmP->Gold);
     77:     TaoLineSearchSetInitialStepLength(tao->linesearch,1.0);
     78:     TaoLineSearchApply(tao->linesearch, tao->solution, &f, blmP->unprojected_gradient, tao->stepdirection, &stepsize, &ls_status);
     79:     TaoAddLineSearchCounts(tao);

     81:     if (ls_status != TAOLINESEARCH_SUCCESS && ls_status != TAOLINESEARCH_SUCCESS_USER) {
     82:       /* Linesearch failed
     83:          Reset factors and use scaled (projected) gradient step */
     84:       ++blmP->reset;

     86:       f = fold;
     87:       VecCopy(blmP->Xold, tao->solution);
     88:       VecCopy(blmP->Gold, blmP->unprojected_gradient);

     90:       if (f != 0.0) {
     91:         delta = 2.0* PetscAbsScalar(f) / (gnorm*gnorm);
     92:       } else {
     93:         delta = 2.0/ (gnorm*gnorm);
     94:       }
     95:       MatLMVMSetDelta(blmP->M,delta);
     96:       MatLMVMReset(blmP->M);
     97:       MatLMVMUpdate(blmP->M, tao->solution, blmP->unprojected_gradient);
     98:       MatLMVMSolve(blmP->M, blmP->unprojected_gradient, tao->stepdirection);
     99:       VecScale(tao->stepdirection, -1.0);

    101:       /* This may be incorrect; linesearch has values fo stepmax and stepmin
    102:          that should be reset. */
    103:       TaoLineSearchSetInitialStepLength(tao->linesearch,1.0);
    104:       TaoLineSearchApply(tao->linesearch,tao->solution,&f, blmP->unprojected_gradient, tao->stepdirection,  &stepsize, &ls_status);
    105:       TaoAddLineSearchCounts(tao);

    107:       if (ls_status != TAOLINESEARCH_SUCCESS && ls_status != TAOLINESEARCH_SUCCESS_USER) {
    108:         tao->reason = TAO_DIVERGED_LS_FAILURE;
    109:         break;
    110:       }
    111:     }

    113:     /* Check for converged */
    114:     VecBoundGradientProjection(blmP->unprojected_gradient, tao->solution, tao->XL, tao->XU, tao->gradient);
    115:     TaoGradientNorm(tao, tao->gradient, NORM_2, &gnorm);

    118:     if (PetscIsInfOrNanReal(f) || PetscIsInfOrNanReal(gnorm)) SETERRQ(PETSC_COMM_SELF,1, "User provided compute function generated Not-a-Number");
    119:     tao->niter++;
    120:     TaoMonitor(tao, tao->niter, f, gnorm, 0.0, stepsize, &reason);
    121:   }
    122:   return(0);
    123: }

    127: static PetscErrorCode TaoSetup_BLMVM(Tao tao)
    128: {
    129:   TAO_BLMVM      *blmP = (TAO_BLMVM *)tao->data;
    130:   PetscInt       n,N;
    132:   KSP            H0ksp;

    135:   /* Existence of tao->solution checked in TaoSetup() */
    136:   VecDuplicate(tao->solution,&blmP->Xold);
    137:   VecDuplicate(tao->solution,&blmP->Gold);
    138:   VecDuplicate(tao->solution, &blmP->unprojected_gradient);

    140:   if (!tao->stepdirection) {
    141:     VecDuplicate(tao->solution, &tao->stepdirection);
    142:   }
    143:   if (!tao->gradient) {
    144:     VecDuplicate(tao->solution,&tao->gradient);
    145:   }
    146:   if (!tao->XL) {
    147:     VecDuplicate(tao->solution,&tao->XL);
    148:     VecSet(tao->XL,PETSC_NINFINITY);
    149:   }
    150:   if (!tao->XU) {
    151:     VecDuplicate(tao->solution,&tao->XU);
    152:     VecSet(tao->XU,PETSC_INFINITY);
    153:   }
    154:   /* Create matrix for the limited memory approximation */
    155:   VecGetLocalSize(tao->solution,&n);
    156:   VecGetSize(tao->solution,&N);
    157:   MatCreateLMVM(((PetscObject)tao)->comm,n,N,&blmP->M);
    158:   MatLMVMAllocateVectors(blmP->M,tao->solution);

    160:   /* If the user has set a matrix to solve as the initial H0, set the options prefix here, and set up the KSP */
    161:   if (blmP->H0) {
    162:     const char *prefix;
    163:     PC H0pc;

    165:     MatLMVMSetH0(blmP->M, blmP->H0);
    166:     MatLMVMGetH0KSP(blmP->M, &H0ksp);

    168:     TaoGetOptionsPrefix(tao, &prefix);
    169:     KSPSetOptionsPrefix(H0ksp, prefix);
    170:     PetscObjectAppendOptionsPrefix((PetscObject)H0ksp, "tao_h0_");
    171:     KSPGetPC(H0ksp, &H0pc);
    172:     PetscObjectAppendOptionsPrefix((PetscObject)H0pc,  "tao_h0_");

    174:     KSPSetFromOptions(H0ksp);
    175:     KSPSetUp(H0ksp);
    176:   }

    178:   return(0);
    179: }

    181: /* ---------------------------------------------------------- */
    184: static PetscErrorCode TaoDestroy_BLMVM(Tao tao)
    185: {
    186:   TAO_BLMVM      *blmP = (TAO_BLMVM *)tao->data;

    190:   if (tao->setupcalled) {
    191:     MatDestroy(&blmP->M);
    192:     VecDestroy(&blmP->unprojected_gradient);
    193:     VecDestroy(&blmP->Xold);
    194:     VecDestroy(&blmP->Gold);
    195:   }

    197:   if (blmP->H0) {
    198:     PetscObjectDereference((PetscObject)blmP->H0);
    199:   }

    201:   PetscFree(tao->data);
    202:   return(0);
    203: }

    205: /*------------------------------------------------------------*/
    208: static PetscErrorCode TaoSetFromOptions_BLMVM(PetscOptionItems* PetscOptionsObject,Tao tao)
    209: {

    213:   PetscOptionsHead(PetscOptionsObject,"Limited-memory variable-metric method for bound constrained optimization");
    214:   TaoLineSearchSetFromOptions(tao->linesearch);
    215:   PetscOptionsTail();
    216:   return(0);
    217: }

    220: /*------------------------------------------------------------*/
    223: static int TaoView_BLMVM(Tao tao, PetscViewer viewer)
    224: {
    225:   TAO_BLMVM      *lmP = (TAO_BLMVM *)tao->data;
    226:   PetscBool      isascii;

    230:   PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii);
    231:   if (isascii) {
    232:     PetscViewerASCIIPushTab(viewer);
    233:     PetscViewerASCIIPrintf(viewer, "Gradient steps: %D\n", lmP->grad);
    234:     PetscViewerASCIIPopTab(viewer);
    235:   }
    236:   return(0);
    237: }

    241: static PetscErrorCode TaoComputeDual_BLMVM(Tao tao, Vec DXL, Vec DXU)
    242: {
    243:   TAO_BLMVM      *blm = (TAO_BLMVM *) tao->data;

    250:   if (!tao->gradient || !blm->unprojected_gradient) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ORDER,"Dual variables don't exist yet or no longer exist.\n");

    252:   VecCopy(tao->gradient,DXL);
    253:   VecAXPY(DXL,-1.0,blm->unprojected_gradient);
    254:   VecSet(DXU,0.0);
    255:   VecPointwiseMax(DXL,DXL,DXU);

    257:   VecCopy(blm->unprojected_gradient,DXU);
    258:   VecAXPY(DXU,-1.0,tao->gradient);
    259:   VecAXPY(DXU,1.0,DXL);
    260:   return(0);
    261: }

    263: /* ---------------------------------------------------------- */
    264: /*MC
    265:   TAOBLMVM - Bounded limited memory variable metric is a quasi-Newton method
    266:          for nonlinear minimization with bound constraints. It is an extension
    267:          of TAOLMVM

    269:   Options Database Keys:
    270: +     -tao_lmm_vectors - number of vectors to use for approximation
    271: .     -tao_lmm_scale_type - "none","scalar","broyden"
    272: .     -tao_lmm_limit_type - "none","average","relative","absolute"
    273: .     -tao_lmm_rescale_type - "none","scalar","gl"
    274: .     -tao_lmm_limit_mu - mu limiting factor
    275: .     -tao_lmm_limit_nu - nu limiting factor
    276: .     -tao_lmm_delta_min - minimum delta value
    277: .     -tao_lmm_delta_max - maximum delta value
    278: .     -tao_lmm_broyden_phi - phi factor for Broyden scaling
    279: .     -tao_lmm_scalar_alpha - alpha factor for scalar scaling
    280: .     -tao_lmm_rescale_alpha - alpha factor for rescaling diagonal
    281: .     -tao_lmm_rescale_beta - beta factor for rescaling diagonal
    282: .     -tao_lmm_scalar_history - amount of history for scalar scaling
    283: .     -tao_lmm_rescale_history - amount of history for rescaling diagonal
    284: -     -tao_lmm_eps - rejection tolerance

    286:   Level: beginner
    287: M*/
    290: PETSC_EXTERN PetscErrorCode TaoCreate_BLMVM(Tao tao)
    291: {
    292:   TAO_BLMVM      *blmP;
    293:   const char     *morethuente_type = TAOLINESEARCHMT;

    297:   tao->ops->setup = TaoSetup_BLMVM;
    298:   tao->ops->solve = TaoSolve_BLMVM;
    299:   tao->ops->view = TaoView_BLMVM;
    300:   tao->ops->setfromoptions = TaoSetFromOptions_BLMVM;
    301:   tao->ops->destroy = TaoDestroy_BLMVM;
    302:   tao->ops->computedual = TaoComputeDual_BLMVM;

    304:   PetscNewLog(tao,&blmP);
    305:   blmP->H0 = NULL;
    306:   tao->data = (void*)blmP;

    308:   /* Override default settings (unless already changed) */
    309:   if (!tao->max_it_changed) tao->max_it = 2000;
    310:   if (!tao->max_funcs_changed) tao->max_funcs = 4000;

    312:   TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);
    313:   TaoLineSearchSetType(tao->linesearch, morethuente_type);
    314:   TaoLineSearchUseTaoRoutines(tao->linesearch,tao);
    315:   TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);
    316:   return(0);
    317: }

    321: PETSC_EXTERN PetscErrorCode TaoLMVMSetH0(Tao tao, Mat H0)
    322: {
    323:   TAO_LMVM       *lmP;
    324:   TAO_BLMVM      *blmP;
    325:   const TaoType  type;
    326:   PetscBool is_lmvm, is_blmvm;

    330:   TaoGetType(tao, &type);
    331:   PetscStrcmp(type, TAOLMVM,  &is_lmvm);
    332:   PetscStrcmp(type, TAOBLMVM, &is_blmvm);

    334:   if (is_lmvm) {
    335:     lmP = (TAO_LMVM *)tao->data;
    336:     PetscObjectReference((PetscObject)H0);
    337:     lmP->H0 = H0;
    338:   } else if (is_blmvm) {
    339:     blmP = (TAO_BLMVM *)tao->data;
    340:     PetscObjectReference((PetscObject)H0);
    341:     blmP->H0 = H0;
    342:   } else SETERRQ(PetscObjectComm((PetscObject)tao), PETSC_ERR_ARG_WRONGSTATE, "This routine applies to TAO_LMVM and TAO_BLMVM.");

    344:   return(0);
    345: }

    349: PETSC_EXTERN PetscErrorCode TaoLMVMGetH0(Tao tao, Mat *H0)
    350: {
    351:   TAO_LMVM       *lmP;
    352:   TAO_BLMVM      *blmP;
    353:   const TaoType  type;
    354:   PetscBool      is_lmvm, is_blmvm;
    355:   Mat            M;

    359:   TaoGetType(tao, &type);
    360:   PetscStrcmp(type, TAOLMVM,  &is_lmvm);
    361:   PetscStrcmp(type, TAOBLMVM, &is_blmvm);

    363:   if (is_lmvm) {
    364:     lmP = (TAO_LMVM *)tao->data;
    365:     M = lmP->M;
    366:   } else if (is_blmvm) {
    367:     blmP = (TAO_BLMVM *)tao->data;
    368:     M = blmP->M;
    369:   } else SETERRQ(PetscObjectComm((PetscObject)tao), PETSC_ERR_ARG_WRONGSTATE, "This routine applies to TAO_LMVM and TAO_BLMVM.");

    371:   MatLMVMGetH0(M, H0);
    372:   return(0);
    373: }

    377: PETSC_EXTERN PetscErrorCode TaoLMVMGetH0KSP(Tao tao, KSP *ksp)
    378: {
    379:   TAO_LMVM       *lmP;
    380:   TAO_BLMVM      *blmP;
    381:   const TaoType  type;
    382:   PetscBool      is_lmvm, is_blmvm;
    383:   Mat            M;

    386:   TaoGetType(tao, &type);
    387:   PetscStrcmp(type, TAOLMVM,  &is_lmvm);
    388:   PetscStrcmp(type, TAOBLMVM, &is_blmvm);

    390:   if (is_lmvm) {
    391:     lmP = (TAO_LMVM *)tao->data;
    392:     M = lmP->M;
    393:   } else if (is_blmvm) {
    394:     blmP = (TAO_BLMVM *)tao->data;
    395:     M = blmP->M;
    396:   } else SETERRQ(PetscObjectComm((PetscObject)tao), PETSC_ERR_ARG_WRONGSTATE, "This routine applies to TAO_LMVM and TAO_BLMVM.");

    398:   MatLMVMGetH0KSP(M, ksp);
    399:   return(0);
    400: }