Date: 2021-02-01T14:42:03+00:00

Actual source code: ex7.c
slepc-3.14.2 2021-02-01
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2020, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: static char help[] = "Solves a generalized eigensystem Ax=kBx with matrices loaded from a file.\n"
     12:   "The command line options are:\n"
     13:   "  -f1 <filename> -f2 <filename>, PETSc binary files containing A and B.\n"
     14:   "  -evecs <filename>, output file to save computed eigenvectors.\n"
     15:   "  -ninitial <nini>, number of user-provided initial guesses.\n"
     16:   "  -finitial <filename>, binary file containing <nini> vectors.\n"
     17:   "  -nconstr <ncon>, number of user-provided constraints.\n"
     18:   "  -fconstr <filename>, binary file containing <ncon> vectors.\n\n";

     20: #include <slepceps.h>

     22: int main(int argc,char **argv)
     23: {
     24:   Mat            A,B;             /* matrices */
     25:   EPS            eps;             /* eigenproblem solver context */
     26:   ST             st;
     27:   KSP            ksp;
     28:   EPSType        type;
     29:   PetscReal      tol;
     30:   Vec            xr,xi,*Iv,*Cv;
     31:   PetscInt       nev,maxit,i,its,lits,nconv,nini=0,ncon=0;
     32:   char           filename[PETSC_MAX_PATH_LEN];
     33:   PetscViewer    viewer;
     34:   PetscBool      flg,evecs,ishermitian,terse;

     37:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;

     39:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     40:         Load the matrices that define the eigensystem, Ax=kBx
     41:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     43:   PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized eigenproblem stored in file.\n\n");
     44:   PetscOptionsGetString(NULL,NULL,"-f1",filename,sizeof(filename),&flg);
     45:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a file name for matrix A with the -f1 option");

     47: #if defined(PETSC_USE_COMPLEX)
     48:   PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrices from binary files...\n");
     49: #else
     50:   PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrices from binary files...\n");
     51: #endif
     52:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
     53:   MatCreate(PETSC_COMM_WORLD,&A);
     54:   MatSetFromOptions(A);
     55:   MatLoad(A,viewer);
     56:   PetscViewerDestroy(&viewer);

     58:   PetscOptionsGetString(NULL,NULL,"-f2",filename,sizeof(filename),&flg);
     59:   if (flg) {
     60:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
     61:     MatCreate(PETSC_COMM_WORLD,&B);
     62:     MatSetFromOptions(B);
     63:     MatLoad(B,viewer);
     64:     PetscViewerDestroy(&viewer);
     65:   } else {
     66:     PetscPrintf(PETSC_COMM_WORLD," Matrix B was not provided, setting B=I\n\n");
     67:     B = NULL;
     68:   }

     70:   MatCreateVecs(A,NULL,&xr);
     71:   MatCreateVecs(A,NULL,&xi);

     73:   /*
     74:      Read user constraints if available
     75:   */
     76:   PetscOptionsGetInt(NULL,NULL,"-nconstr",&ncon,&flg);
     77:   if (flg) {
     78:     if (ncon<=0) SETERRQ(PETSC_COMM_WORLD,1,"The number of constraints must be >0");
     79:     PetscOptionsGetString(NULL,NULL,"-fconstr",filename,sizeof(filename),&flg);
     80:     if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must specify the name of the file storing the constraints");
     81:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
     82:     VecDuplicateVecs(xr,ncon,&Cv);
     83:     for (i=0;i<ncon;i++) {
     84:       VecLoad(Cv[i],viewer);
     85:     }
     86:     PetscViewerDestroy(&viewer);
     87:   }

     89:   /*
     90:      Read initial guesses if available
     91:   */
     92:   PetscOptionsGetInt(NULL,NULL,"-ninitial",&nini,&flg);
     93:   if (flg) {
     94:     if (nini<=0) SETERRQ(PETSC_COMM_WORLD,1,"The number of initial vectors must be >0");
     95:     PetscOptionsGetString(NULL,NULL,"-finitial",filename,sizeof(filename),&flg);
     96:     if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must specify the name of the file containing the initial vectors");
     97:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
     98:     VecDuplicateVecs(xr,nini,&Iv);
     99:     for (i=0;i<nini;i++) {
    100:       VecLoad(Iv[i],viewer);
    101:     }
    102:     PetscViewerDestroy(&viewer);
    103:   }

    105:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    106:                 Create the eigensolver and set various options
    107:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    109:   /*
    110:      Create eigensolver context
    111:   */
    112:   EPSCreate(PETSC_COMM_WORLD,&eps);

    114:   /*
    115:      Set operators. In this case, it is a generalized eigenvalue problem
    116:   */
    117:   EPSSetOperators(eps,A,B);

    119:   /*
    120:      If the user provided initial guesses or constraints, pass them here
    121:   */
    122:   EPSSetInitialSpace(eps,nini,Iv);
    123:   EPSSetDeflationSpace(eps,ncon,Cv);

    125:   /*
    126:      Set solver parameters at runtime
    127:   */
    128:   EPSSetFromOptions(eps);

    130:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    131:                       Solve the eigensystem
    132:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    134:   EPSSolve(eps);

    136:   /*
    137:      Optional: Get some information from the solver and display it
    138:   */
    139:   EPSGetIterationNumber(eps,&its);
    140:   PetscPrintf(PETSC_COMM_WORLD," Number of iterations of the method: %D\n",its);
    141:   EPSGetST(eps,&st);
    142:   STGetKSP(st,&ksp);
    143:   KSPGetTotalIterations(ksp,&lits);
    144:   PetscPrintf(PETSC_COMM_WORLD," Number of linear iterations of the method: %D\n",lits);
    145:   EPSGetType(eps,&type);
    146:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
    147:   EPSGetDimensions(eps,&nev,NULL,NULL);
    148:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
    149:   EPSGetTolerances(eps,&tol,&maxit);
    150:   PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%D\n",(double)tol,maxit);

    152:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    153:                     Display solution and clean up
    154:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    156:   /*
    157:      Show detailed info unless -terse option is given by user
    158:    */
    159:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    160:   if (terse) {
    161:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
    162:   } else {
    163:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    164:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
    165:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    166:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    167:   }

    169:   /*
    170:      Save eigenvectors, if requested
    171:   */
    172:   PetscOptionsGetString(NULL,NULL,"-evecs",filename,sizeof(filename),&evecs);
    173:   EPSGetConverged(eps,&nconv);
    174:   if (nconv>0 && evecs) {
    175:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_WRITE,&viewer);
    176:     EPSIsHermitian(eps,&ishermitian);
    177:     for (i=0;i<nconv;i++) {
    178:       EPSGetEigenvector(eps,i,xr,xi);
    179:       VecView(xr,viewer);
    180: #if !defined(PETSC_USE_COMPLEX)
    181:       if (!ishermitian) { VecView(xi,viewer); }
    182: #endif
    183:     }
    184:     PetscViewerDestroy(&viewer);
    185:   }

    187:   /*
    188:      Free work space
    189:   */
    190:   EPSDestroy(&eps);
    191:   MatDestroy(&A);
    192:   MatDestroy(&B);
    193:   VecDestroy(&xr);
    194:   VecDestroy(&xi);
    195:   if (nini > 0) {
    196:     VecDestroyVecs(nini,&Iv);
    197:   }
    198:   if (ncon > 0) {
    199:     VecDestroyVecs(ncon,&Cv);
    200:   }
    201:   SlepcFinalize();
    202:   return ierr;
    203: }

    205: /*TEST

    207:    test:
    208:       suffix: 1
    209:       args: -f1 ${SLEPC_DIR}/share/slepc/datafiles/matrices/bfw62a.petsc -f2 ${SLEPC_DIR}/share/slepc/datafiles/matrices/bfw62b.petsc -eps_nev 4 -terse
    210:       requires: double !complex !define(PETSC_USE_64BIT_INDICES)

    212:    test:
    213:       suffix: ciss_1
    214:       args: -f1 ${DATAFILESPATH}/matrices/complex/mhd1280a.petsc -f2 ${DATAFILESPATH}/matrices/complex/mhd1280b.petsc -eps_type ciss -eps_ciss_usest 0 -eps_ciss_quadrule chebyshev -rg_type ring -rg_ring_center 0 -rg_ring_radius .49 -rg_ring_width 0.2 -rg_ring_startangle .25 -rg_ring_endangle .49 -terse
    215:       requires: complex datafilespath !define(PETSC_USE_64BIT_INDICES)
    216:       timeoutfactor: 2

    218: TEST*/