1: #include <../src/tao/complementarity/impls/ssls/ssls.h>

  5: PetscErrorCode TaoSetUp_SSFLS(Tao tao)
  6: {
  7:   TAO_SSLS       *ssls = (TAO_SSLS *)tao->data;

 11:   VecDuplicate(tao->solution,&tao->gradient);
 12:   VecDuplicate(tao->solution,&tao->stepdirection);
 13:   VecDuplicate(tao->solution,&ssls->w);
 14:   VecDuplicate(tao->solution,&ssls->ff);
 15:   VecDuplicate(tao->solution,&ssls->dpsi);
 16:   VecDuplicate(tao->solution,&ssls->da);
 17:   VecDuplicate(tao->solution,&ssls->db);
 18:   VecDuplicate(tao->solution,&ssls->t1);
 19:   VecDuplicate(tao->solution,&ssls->t2);
 20:   if (!tao->XL) {
 21:     VecDuplicate(tao->solution,&tao->XL);
 22:   }
 23:   if (!tao->XU) {
 24:     VecDuplicate(tao->solution,&tao->XU);
 25:   }
 26:   TaoLineSearchSetVariableBounds(tao->linesearch,tao->XL,tao->XU);
 27:   return(0);
 28: }

 32: static PetscErrorCode TaoSolve_SSFLS(Tao tao)
 33: {
 34:   TAO_SSLS                     *ssls = (TAO_SSLS *)tao->data;
 35:   PetscReal                    psi, ndpsi, normd, innerd, t=0;
 36:   PetscReal                    delta, rho;
 37:   TaoConvergedReason           reason;
 38:   TaoLineSearchConvergedReason ls_reason;
 39:   PetscErrorCode               ierr;

 42:   /* Assume that Setup has been called!
 43:      Set the structure for the Jacobian and create a linear solver. */
 44:   delta = ssls->delta;
 45:   rho = ssls->rho;

 47:   TaoComputeVariableBounds(tao);
 48:   /* Project solution inside bounds */
 49:   VecMedian(tao->XL,tao->solution,tao->XU,tao->solution);
 50:   TaoLineSearchSetObjectiveAndGradientRoutine(tao->linesearch,Tao_SSLS_FunctionGradient,tao);
 51:   TaoLineSearchSetObjectiveRoutine(tao->linesearch,Tao_SSLS_Function,tao);

 53:   /* Calculate the function value and fischer function value at the
 54:      current iterate */
 55:   TaoLineSearchComputeObjectiveAndGradient(tao->linesearch,tao->solution,&psi,ssls->dpsi);
 56:   VecNorm(ssls->dpsi,NORM_2,&ndpsi);

 58:   while (PETSC_TRUE) {
 59:     ierr=PetscInfo3(tao, "iter: %D, merit: %g, ndpsi: %g\n",tao->niter, (double)ssls->merit, (double)ndpsi);
 60:     /* Check the termination criteria */
 61:     TaoMonitor(tao,tao->niter,ssls->merit,ndpsi,0.0,t,&reason);
 62:     if (reason!=TAO_CONTINUE_ITERATING) break;
 63:     tao->niter++;

 65:     /* Calculate direction.  (Really negative of newton direction.  Therefore,
 66:        rest of the code uses -d.) */
 67:     KSPSetOperators(tao->ksp,tao->jacobian,tao->jacobian_pre);
 68:     KSPSolve(tao->ksp,ssls->ff,tao->stepdirection);
 69:     KSPGetIterationNumber(tao->ksp,&tao->ksp_its);
 70:     tao->ksp_tot_its+=tao->ksp_its;

 72:     VecCopy(tao->stepdirection,ssls->w);
 73:     VecScale(ssls->w,-1.0);
 74:     VecBoundGradientProjection(ssls->w,tao->solution,tao->XL,tao->XU,ssls->w);

 76:     VecNorm(ssls->w,NORM_2,&normd);
 77:     VecDot(ssls->w,ssls->dpsi,&innerd);

 79:     /* Make sure that we have a descent direction */
 80:     if (innerd >= -delta*PetscPowReal(normd, rho)) {
 81:       PetscInfo(tao, "newton direction not descent\n");
 82:       VecCopy(ssls->dpsi,tao->stepdirection);
 83:       VecDot(ssls->w,ssls->dpsi,&innerd);
 84:     }

 86:     VecScale(tao->stepdirection, -1.0);
 87:     innerd = -innerd;

 89:     TaoLineSearchSetInitialStepLength(tao->linesearch,1.0);
 90:     TaoLineSearchApply(tao->linesearch,tao->solution,&psi,ssls->dpsi,tao->stepdirection,&t,&ls_reason);
 91:     VecNorm(ssls->dpsi,NORM_2,&ndpsi);
 92:   }
 93:   return(0);
 94: }

 98: PetscErrorCode TaoDestroy_SSFLS(Tao tao)
 99: {
100:   TAO_SSLS       *ssls = (TAO_SSLS *)tao->data;

104:   VecDestroy(&ssls->ff);
105:   VecDestroy(&ssls->w);
106:   VecDestroy(&ssls->dpsi);
107:   VecDestroy(&ssls->da);
108:   VecDestroy(&ssls->db);
109:   VecDestroy(&ssls->t1);
110:   VecDestroy(&ssls->t2);
111:   PetscFree(tao->data);
112:   return(0);
113: }

115: /* ---------------------------------------------------------- */
116: /*MC
117:    TAOSSFLS - Semi-smooth feasible linesearch algorithm for solving
118:        complementarity constraints

120:    Options Database Keys:
121: + -tao_ssls_delta - descent test fraction
122: - -tao_ssls_rho - descent test power

124:    Level: beginner
125: M*/

129: PETSC_EXTERN PetscErrorCode TaoCreate_SSFLS(Tao tao)
130: {
131:   TAO_SSLS       *ssls;
133:   const char     *armijo_type = TAOLINESEARCHARMIJO;

136:   PetscNewLog(tao,&ssls);
137:   tao->data = (void*)ssls;
138:   tao->ops->solve=TaoSolve_SSFLS;
139:   tao->ops->setup=TaoSetUp_SSFLS;
140:   tao->ops->view=TaoView_SSLS;
141:   tao->ops->setfromoptions = TaoSetFromOptions_SSLS;
142:   tao->ops->destroy = TaoDestroy_SSFLS;

144:   ssls->delta = 1e-10;
145:   ssls->rho = 2.1;

147:   TaoLineSearchCreate(((PetscObject)tao)->comm,&tao->linesearch);
148:   TaoLineSearchSetType(tao->linesearch,armijo_type);
149:   TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);
150:   TaoLineSearchSetFromOptions(tao->linesearch);
151:   /* Linesearch objective and objectivegradient routines are  set in solve routine */
152:   KSPCreate(((PetscObject)tao)->comm,&tao->ksp);
153:   KSPSetOptionsPrefix(tao->ksp,tao->hdr.prefix);

155:   /* Override default settings (unless already changed) */
156:   if (!tao->max_it_changed) tao->max_it = 2000;
157:   if (!tao->max_funcs_changed) tao->max_funcs = 4000;
158:   if (!tao->fatol_changed) tao->fatol = 0;
159:   if (!tao->frtol_changed) tao->frtol = 0;
160:   if (!tao->gttol_changed) tao->gttol = 0;
161:   if (!tao->grtol_changed) tao->grtol = 0;
162: #if defined(PETSC_USE_REAL_SINGLE)
163:   if (!tao->gatol_changed) tao->gatol = 1.0e-6;
164:   if (!tao->fmin_changed)  tao->fmin = 1.0e-4;
165: #else
166:   if (!tao->gatol_changed) tao->gatol = 1.0e-16;
167:   if (!tao->fmin_changed)  tao->fmin = 1.0e-8;
168: #endif
169:   return(0);
170: }