Actual source code: butterfly.c

slepc-3.7.1 2016-05-27
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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: */
 21: /*
 22:    This example implements one of the problems found at
 23:        NLEVP: A Collection of Nonlinear Eigenvalue Problems,
 24:        The University of Manchester.
 25:    The details of the collection can be found at:
 26:        [1] T. Betcke et al., "NLEVP: A Collection of Nonlinear Eigenvalue
 27:            Problems", ACM Trans. Math. Software 39(2), Article 7, 2013.

 29:    The butterfly problem is a quartic PEP with T-even structure.
 30: */

 32: static char help[] = "Quartic polynomial eigenproblem with T-even structure.\n\n"
 33:   "The command line options are:\n"
 34:   "  -m <m>, grid size, the dimension of the matrices is n=m*m.\n"
 35:   "  -c <array>, problem parameters, must be 10 comma-separated real values.\n\n";

 37: #include <slepcpep.h>

 39: #define NMAT 5

 43: int main(int argc,char **argv)
 44: {
 45:   Mat            A[NMAT];         /* problem matrices */
 46:   PEP            pep;             /* polynomial eigenproblem solver context */
 47:   PetscInt       n,m=8,k,II,Istart,Iend,i,j;
 48:   PetscReal      c[10] = { 0.6, 1.3, 1.3, 0.1, 0.1, 1.2, 1.0, 1.0, 1.2, 1.0 };
 49:   PetscBool      flg;
 50:   PetscBool      terse;

 53:   SlepcInitialize(&argc,&argv,(char*)0,help);

 55:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 56:   n = m*m;
 57:   k = 10;
 58:   PetscOptionsGetRealArray(NULL,NULL,"-c",c,&k,&flg);
 59:   if (flg && k!=10) SETERRQ1(PETSC_COMM_WORLD,1,"The number of parameters -c should be 10, you provided %D",k); 
 60:   PetscPrintf(PETSC_COMM_WORLD,"\nButterfly problem, n=%D (m=%D)\n\n",n,m);

 62:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
 63:                      Compute the polynomial matrices 
 64:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 66:   /* initialize matrices */
 67:   for (i=0;i<NMAT;i++) {
 68:     MatCreate(PETSC_COMM_WORLD,&A[i]);
 69:     MatSetSizes(A[i],PETSC_DECIDE,PETSC_DECIDE,n,n);
 70:     MatSetFromOptions(A[i]);
 71:     MatSetUp(A[i]);
 72:   }
 73:   MatGetOwnershipRange(A[0],&Istart,&Iend);

 75:   /* A0 */
 76:   for (II=Istart;II<Iend;II++) {
 77:     i = II/m; j = II-i*m;
 78:     MatSetValue(A[0],II,II,4.0*c[0]/6.0+4.0*c[1]/6.0,INSERT_VALUES);
 79:     if (j>0) { MatSetValue(A[0],II,II-1,c[0]/6.0,INSERT_VALUES); }
 80:     if (j<m-1) { MatSetValue(A[0],II,II+1,c[0]/6.0,INSERT_VALUES); }
 81:     if (i>0) { MatSetValue(A[0],II,II-m,c[1]/6.0,INSERT_VALUES); }
 82:     if (i<m-1) { MatSetValue(A[0],II,II+m,c[1]/6.0,INSERT_VALUES); }
 83:   }

 85:   /* A1 */
 86:   for (II=Istart;II<Iend;II++) {
 87:     i = II/m; j = II-i*m;
 88:     if (j>0) { MatSetValue(A[1],II,II-1,c[2],INSERT_VALUES); }
 89:     if (j<m-1) { MatSetValue(A[1],II,II+1,-c[2],INSERT_VALUES); }
 90:     if (i>0) { MatSetValue(A[1],II,II-m,c[3],INSERT_VALUES); }
 91:     if (i<m-1) { MatSetValue(A[1],II,II+m,-c[3],INSERT_VALUES); }
 92:   }

 94:   /* A2 */
 95:   for (II=Istart;II<Iend;II++) {
 96:     i = II/m; j = II-i*m;
 97:     MatSetValue(A[2],II,II,-2.0*c[4]-2.0*c[5],INSERT_VALUES);
 98:     if (j>0) { MatSetValue(A[2],II,II-1,c[4],INSERT_VALUES); }
 99:     if (j<m-1) { MatSetValue(A[2],II,II+1,c[4],INSERT_VALUES); }
100:     if (i>0) { MatSetValue(A[2],II,II-m,c[5],INSERT_VALUES); }
101:     if (i<m-1) { MatSetValue(A[2],II,II+m,c[5],INSERT_VALUES); }
102:   }

104:   /* A3 */
105:   for (II=Istart;II<Iend;II++) {
106:     i = II/m; j = II-i*m;
107:     if (j>0) { MatSetValue(A[3],II,II-1,c[6],INSERT_VALUES); }
108:     if (j<m-1) { MatSetValue(A[3],II,II+1,-c[6],INSERT_VALUES); }
109:     if (i>0) { MatSetValue(A[3],II,II-m,c[7],INSERT_VALUES); }
110:     if (i<m-1) { MatSetValue(A[3],II,II+m,-c[7],INSERT_VALUES); }
111:   }

113:   /* A4 */
114:   for (II=Istart;II<Iend;II++) {
115:     i = II/m; j = II-i*m;
116:     MatSetValue(A[4],II,II,2.0*c[8]+2.0*c[9],INSERT_VALUES);
117:     if (j>0) { MatSetValue(A[4],II,II-1,-c[8],INSERT_VALUES); }
118:     if (j<m-1) { MatSetValue(A[4],II,II+1,-c[8],INSERT_VALUES); }
119:     if (i>0) { MatSetValue(A[4],II,II-m,-c[9],INSERT_VALUES); }
120:     if (i<m-1) { MatSetValue(A[4],II,II+m,-c[9],INSERT_VALUES); }
121:   }

123:   /* assemble matrices */
124:   for (i=0;i<NMAT;i++) {
125:     MatAssemblyBegin(A[i],MAT_FINAL_ASSEMBLY);
126:   }
127:   for (i=0;i<NMAT;i++) {
128:     MatAssemblyEnd(A[i],MAT_FINAL_ASSEMBLY);
129:   }

131:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
132:                 Create the eigensolver and solve the problem
133:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

135:   PEPCreate(PETSC_COMM_WORLD,&pep);
136:   PEPSetOperators(pep,NMAT,A);
137:   PEPSetFromOptions(pep);
138:   PEPSolve(pep);

140:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
141:                     Display solution and clean up
142:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
143:   
144:   /* show detailed info unless -terse option is given by user */
145:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
146:   if (terse) {
147:     PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
148:   } else {
149:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
150:     PEPReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
151:     PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
152:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
153:   }
154:   PEPDestroy(&pep);
155:   for (i=0;i<NMAT;i++) {
156:     MatDestroy(&A[i]);
157:   }
158:   SlepcFinalize();
159:   return ierr;
160: }