Actual source code: test2.c

slepc-3.7.4 2017-05-17
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.

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

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

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Test BV orthogonalization functions.\n\n";

 24: #include <slepcbv.h>

 28: int main(int argc,char **argv)
 29: {
 31:   BV             X,Y,Z;
 32:   Mat            M,R;
 33:   Vec            v,t,e;
 34:   PetscInt       i,j,n=20,k=8;
 35:   PetscViewer    view;
 36:   PetscBool      verbose;
 37:   PetscReal      norm;
 38:   PetscScalar    alpha;

 40:   SlepcInitialize(&argc,&argv,(char*)0,help);
 41:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 42:   PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
 43:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
 44:   PetscPrintf(PETSC_COMM_WORLD,"Test BV orthogonalization with %D columns of length %D.\n",k,n);

 46:   /* Create template vector */
 47:   VecCreate(PETSC_COMM_WORLD,&t);
 48:   VecSetSizes(t,PETSC_DECIDE,n);
 49:   VecSetFromOptions(t);

 51:   /* Create BV object X */
 52:   BVCreate(PETSC_COMM_WORLD,&X);
 53:   PetscObjectSetName((PetscObject)X,"X");
 54:   BVSetSizesFromVec(X,t,k);
 55:   BVSetFromOptions(X);

 57:   /* Set up viewer */
 58:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&view);
 59:   if (verbose) {
 60:     PetscViewerPushFormat(view,PETSC_VIEWER_ASCII_MATLAB);
 61:   }

 63:   /* Fill X entries */
 64:   for (j=0;j<k;j++) {
 65:     BVGetColumn(X,j,&v);
 66:     VecSet(v,0.0);
 67:     for (i=0;i<=n/2;i++) {
 68:       if (i+j<n) {
 69:         alpha = (3.0*i+j-2)/(2*(i+j+1));
 70:         VecSetValue(v,i+j,alpha,INSERT_VALUES);
 71:       }
 72:     }
 73:     VecAssemblyBegin(v);
 74:     VecAssemblyEnd(v);
 75:     BVRestoreColumn(X,j,&v);
 76:   }
 77:   if (verbose) {
 78:     BVView(X,view);
 79:   }

 81:   /* Create copies on Y and Z */
 82:   BVDuplicate(X,&Y);
 83:   PetscObjectSetName((PetscObject)Y,"Y");
 84:   BVCopy(X,Y);
 85:   BVDuplicate(X,&Z);
 86:   PetscObjectSetName((PetscObject)Z,"Z");
 87:   BVCopy(X,Z);

 89:   /* Test BVOrthogonalizeColumn */
 90:   for (j=0;j<k;j++) {
 91:     BVOrthogonalizeColumn(X,j,NULL,&norm,NULL);
 92:     alpha = 1.0/norm;
 93:     BVScaleColumn(X,j,alpha);
 94:   }
 95:   if (verbose) {
 96:     BVView(X,view);
 97:   }

 99:   /* Check orthogonality */
100:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&M);
101:   BVDot(X,X,M);
102:   MatShift(M,-1.0);
103:   MatNorm(M,NORM_1,&norm);
104:   if (norm<100*PETSC_MACHINE_EPSILON) {
105:     PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality < 100*eps\n");
106:   } else {
107:     PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality: %g\n",(double)norm);
108:   }

110:   /* Test BVOrthogonalize */
111:   MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&R);
112:   PetscObjectSetName((PetscObject)R,"R");
113:   BVOrthogonalize(Y,R);
114:   if (verbose) {
115:     BVView(Y,view);
116:     MatView(R,view);
117:   }

119:   /* Check orthogonality */
120:   BVDot(Y,Y,M);
121:   MatShift(M,-1.0);
122:   MatNorm(M,NORM_1,&norm);
123:   if (norm<100*PETSC_MACHINE_EPSILON) {
124:     PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality < 100*eps\n");
125:   } else {
126:     PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality: %g\n",(double)norm);
127:   }

129:   /* Check residual */
130:   BVMult(Z,-1.0,1.0,Y,R);
131:   BVNorm(Z,NORM_FROBENIUS,&norm);
132:   if (norm<100*PETSC_MACHINE_EPSILON) {
133:     PetscPrintf(PETSC_COMM_WORLD,"Residual ||X-QR|| < 100*eps\n");
134:   } else {
135:     PetscPrintf(PETSC_COMM_WORLD,"Residual ||X-QR||: %g\n",(double)norm);
136:   }

138:   /* Test BVOrthogonalizeVec */
139:   VecDuplicate(t,&e);
140:   VecSet(e,1.0);
141:   BVOrthogonalizeVec(X,e,NULL,&norm,NULL);
142:   PetscPrintf(PETSC_COMM_WORLD,"Norm of ones(n,1) after orthogonalizing against X: %g\n",(double)norm);

144:   MatDestroy(&M);
145:   MatDestroy(&R);
146:   BVDestroy(&X);
147:   BVDestroy(&Y);
148:   BVDestroy(&Z);
149:   VecDestroy(&e);
150:   VecDestroy(&t);
151:   SlepcFinalize();
152:   return ierr;
153: }