Actual source code: dvdgd2.c

slepc-3.7.0 2016-05-16
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  1: /*
  2:   SLEPc eigensolver: "davidson"

  4:   Step: improve the eigenvectors X with GD2

  6:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  7:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  8:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

 10:    This file is part of SLEPc.

 12:    SLEPc is free software: you can redistribute it and/or modify it under  the
 13:    terms of version 3 of the GNU Lesser General Public License as published by
 14:    the Free Software Foundation.

 16:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 17:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 18:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 19:    more details.

 21:    You  should have received a copy of the GNU Lesser General  Public  License
 22:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 23:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 24: */

 26:  #include davidson.h

 28: typedef struct {
 29:   PetscInt size_X;
 30: } dvdImprovex_gd2;

 34: static PetscErrorCode dvd_improvex_gd2_d(dvdDashboard *d)
 35: {
 36:   PetscErrorCode  ierr;
 37:   dvdImprovex_gd2 *data = (dvdImprovex_gd2*)d->improveX_data;

 40:   /* Free local data and objects */
 41:   PetscFree(data);
 42:   return(0);
 43: }

 47: static PetscErrorCode dvd_improvex_gd2_gen(dvdDashboard *d,PetscInt r_s,PetscInt r_e,PetscInt *size_D)
 48: {
 49:   dvdImprovex_gd2 *data = (dvdImprovex_gd2*)d->improveX_data;
 50:   PetscErrorCode  ierr;
 51:   PetscInt        i,j,n,s,ld,k,lv,kv,max_size_D;
 52:   PetscScalar     *pX,*b;
 53:   Vec             *Ax,*Bx,v,*x;
 54:   Mat             M;
 55:   BV              X;

 58:   /* Compute the number of pairs to improve */
 59:   BVGetActiveColumns(d->eps->V,&lv,&kv);
 60:   max_size_D = d->eps->ncv-kv;
 61:   n = PetscMin(PetscMin(data->size_X*2,max_size_D),(r_e-r_s)*2)/2;
 62: #if !defined(PETSC_USE_COMPLEX)
 63:   /* If the last eigenvalue is a complex conjugate pair, n is increased by one */
 64:   for (i=0; i<n; i++) {
 65:     if (d->eigi[i] != 0.0) i++;
 66:   }
 67:   if (i > n) {
 68:     n = PetscMin(PetscMin(data->size_X*2,max_size_D),(n+1)*2)/2;
 69:     if (i > n) n--;
 70:   }
 71: #endif

 73:   /* Quick exit */
 74:   if (max_size_D == 0 || r_e-r_s <= 0 || n == 0) {
 75:    *size_D = 0;
 76:     return(0);
 77:   }

 79:   BVDuplicateResize(d->eps->V,4,&X);
 80:   MatCreateSeqDense(PETSC_COMM_SELF,4,2,NULL,&M);

 82:   /* Compute the eigenvectors of the selected pairs */
 83:   for (i=0;i<n;) {
 84:     k = r_s+i;
 85:     DSVectors(d->eps->ds,DS_MAT_X,&k,NULL);
 86:     i = k+1; /* skip complex conjugate pairs */
 87:   }
 88:   DSGetArray(d->eps->ds,DS_MAT_X,&pX);
 89:   DSGetLeadingDimension(d->eps->ds,&ld);

 91:   SlepcVecPoolGetVecs(d->auxV,n,&Ax);
 92:   SlepcVecPoolGetVecs(d->auxV,n,&Bx);

 94:   /* Bx <- B*X(i) */
 95:   if (d->BX) {
 96:     /* Compute the norms of the eigenvectors */
 97:     if (d->correctXnorm) {
 98:       dvd_improvex_compute_X(d,r_s,r_s+n,Bx,pX,ld);
 99:     } else {
100:       for (i=0;i<n;i++) d->nX[r_s+i] = 1.0;
101:     }
102:     for (i=0;i<n;i++) {
103:       BVMultVec(d->BX,1.0,0.0,Bx[i],&pX[ld*(r_s+i)]);
104:     }
105:   } else if (d->B) {
106:     SlepcVecPoolGetVecs(d->auxV,1,&x);
107:     for (i=0;i<n;i++) {
108:       /* auxV(0) <- X(i) */
109:       dvd_improvex_compute_X(d,r_s+i,r_s+i+1,x,pX,ld);
110:       /* Bx(i) <- B*auxV(0) */
111:       MatMult(d->B,x[0],Bx[i]);
112:     }
113:     SlepcVecPoolRestoreVecs(d->auxV,1,&x);
114:   } else {
115:     /* Bx <- X */
116:     dvd_improvex_compute_X(d,r_s,r_s+n,Bx,pX,ld);
117:   }

119:   /* Ax <- A*X(i) */
120:   for (i=0;i<n;i++) {
121:     BVMultVec(d->AX,1.0,0.0,Ax[i],&pX[ld*(i+r_s)]);
122:   }

124:   DSRestoreArray(d->eps->ds,DS_MAT_X,&pX);

126:   for (i=0,s=0;i<n;i+=s) {
127: #if !defined(PETSC_USE_COMPLEX)
128:     if (d->eigi[r_s+i] != 0.0) {
129:        /* [Ax_i Ax_i+1 Bx_i Bx_i+1]*= [   1        0
130:                                           0        1
131:                                        -eigr_i -eigi_i
132:                                         eigi_i -eigr_i] */
133:       MatDenseGetArray(M,&b);
134:       b[0] = b[5] = 1.0/d->nX[r_s+i];
135:       b[2] = b[7] = -d->eigr[r_s+i]/d->nX[r_s+i];
136:       b[6] = -(b[3] = d->eigi[r_s+i]/d->nX[r_s+i]);
137:       b[1] = b[4] = 0.0;
138:       MatDenseRestoreArray(M,&b);
139:       BVInsertVec(X,0,Ax[i]);
140:       BVInsertVec(X,1,Ax[i+1]);
141:       BVInsertVec(X,2,Bx[i]);
142:       BVInsertVec(X,3,Bx[i+1]);
143:       BVSetActiveColumns(X,0,4);
144:       BVMultInPlace(X,M,0,2);
145:       BVCopyVec(X,0,Ax[i]);
146:       BVCopyVec(X,1,Ax[i+1]);
147:       s = 2;
148:     } else
149: #endif
150:     {
151:       /* [Ax_i Bx_i]*= [ 1/nX_i    conj(eig_i/nX_i)
152:                        -eig_i/nX_i     1/nX_i       ] */
153:       MatDenseGetArray(M,&b);
154:       b[0] = 1.0/d->nX[r_s+i];
155:       b[1] = -d->eigr[r_s+i]/d->nX[r_s+i];
156:       b[4] = PetscConj(d->eigr[r_s+i]/d->nX[r_s+i]);
157:       b[5] = 1.0/d->nX[r_s+i];
158:       MatDenseRestoreArray(M,&b);
159:       BVInsertVec(X,0,Ax[i]);
160:       BVInsertVec(X,1,Bx[i]);
161:       BVSetActiveColumns(X,0,2);
162:       BVMultInPlace(X,M,0,2);
163:       BVCopyVec(X,0,Ax[i]);
164:       BVCopyVec(X,1,Bx[i]);
165:       s = 1;
166:     }
167:     for (j=0;j<s;j++) d->nX[r_s+i+j] = 1.0;

169:     /* Ax = R <- P*(Ax - eig_i*Bx) */
170:     d->calcpairs_proj_res(d,r_s+i,r_s+i+s,&Ax[i]);

172:     /* Check if the first eigenpairs are converged */
173:     if (i == 0) {
174:       d->preTestConv(d,0,s,s,&d->npreconv);
175:       if (d->npreconv > 0) break;
176:     }
177:   }

179:   /* D <- K*[Ax Bx] */
180:   if (d->npreconv == 0) {
181:     for (i=0;i<n;i++) {
182:       BVGetColumn(d->eps->V,kv+i,&v);
183:       d->improvex_precond(d,r_s+i,Ax[i],v);
184:       BVRestoreColumn(d->eps->V,kv+i,&v);
185:     }
186:     for (i=n;i<n*2;i++) {
187:       BVGetColumn(d->eps->V,kv+i,&v);
188:       d->improvex_precond(d,r_s+i-n,Bx[i-n],v);
189:       BVRestoreColumn(d->eps->V,kv+i,&v);
190:     }
191:     *size_D = 2*n;
192: #if !defined(PETSC_USE_COMPLEX)
193:     if (d->eigi[r_s] != 0.0) {
194:       s = 4;
195:     } else
196: #endif
197:     {
198:       s = 2;
199:     }
200:     /* Prevent that short vectors are discarded in the orthogonalization */
201:     for (i=0; i<s && i<*size_D; i++) {
202:       if (d->eps->errest[d->nconv+r_s+i] > PETSC_MACHINE_EPSILON && d->eps->errest[d->nconv+r_s+i] < PETSC_MAX_REAL) {
203:         BVScaleColumn(d->eps->V,i+kv,1.0/d->eps->errest[d->nconv+r_s+i]);
204:       }
205:     }
206:   } else *size_D = 0;

208:   SlepcVecPoolRestoreVecs(d->auxV,n,&Bx);
209:   SlepcVecPoolRestoreVecs(d->auxV,n,&Ax);
210:   BVDestroy(&X);
211:   MatDestroy(&M);
212:   return(0);
213: }

217: PetscErrorCode dvd_improvex_gd2(dvdDashboard *d,dvdBlackboard *b,KSP ksp,PetscInt max_bs)
218: {
219:   PetscErrorCode  ierr;
220:   dvdImprovex_gd2 *data;
221:   PC              pc;

224:   /* Setting configuration constrains */
225:   /* If the arithmetic is real and the problem is not Hermitian, then
226:      the block size is incremented in one */
227: #if !defined(PETSC_USE_COMPLEX)
228:   if (!DVD_IS(d->sEP, DVD_EP_HERMITIAN)) {
229:     max_bs++;
230:     b->max_size_P = PetscMax(b->max_size_P,2);
231:   } else
232: #endif
233:   {
234:     b->max_size_P = PetscMax(b->max_size_P,1);
235:   }
236:   b->max_size_X = PetscMax(b->max_size_X,max_bs);

238:   /* Setup the preconditioner */
239:   if (ksp) {
240:     KSPGetPC(ksp,&pc);
241:     dvd_static_precond_PC(d,b,pc);
242:   } else {
243:     dvd_static_precond_PC(d,b,0);
244:   }

246:   /* Setup the step */
247:   if (b->state >= DVD_STATE_CONF) {
248:     PetscNewLog(d->eps,&data);
249:     d->improveX_data = data;
250:     data->size_X = b->max_size_X;
251:     d->improveX = dvd_improvex_gd2_gen;

253:     EPSDavidsonFLAdd(&d->destroyList,dvd_improvex_gd2_d);
254:   }
255:   return(0);
256: }