Date: 2021-02-01T14:42:19+00:00

Actual source code: gun.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: */
     10: /*
     11:    This example implements one of the problems found at
     12:        NLEVP: A Collection of Nonlinear Eigenvalue Problems,
     13:        The University of Manchester.
     14:    The details of the collection can be found at:
     15:        [1] T. Betcke et al., "NLEVP: A Collection of Nonlinear Eigenvalue
     16:            Problems", ACM Trans. Math. Software 39(2), Article 7, 2013.

     18:    The gun problem arises from model of a radio-frequency gun cavity, with
     19:    the complex nonlinear function
     20:    T(lambda) = K-lambda*M+i*lambda^(1/2)*W1+i*(lambda-108.8774^2)^(1/2)*W2

     22:    Data files can be downloaded from https://slepc.upv.es/datafiles
     23: */

     25: static char help[] = "Radio-frequency gun cavity.\n\n"
     26:   "The command line options are:\n"
     27:   "-K <filename1> -M <filename2> -W1 <filename3> -W2 <filename4>, where filename1,..,filename4 are files containing the matrices in PETSc binary form defining the GUN problem.\n\n";

     29: #include <slepcnep.h>

     31: #define NMAT 4
     32: #define SIGMA 108.8774

     34: int main(int argc,char **argv)
     35: {
     37:   Mat            A[NMAT];         /* problem matrices */
     38:   FN             f[NMAT];         /* functions to define the nonlinear operator */
     39:   FN             ff[2];           /* auxiliary functions to define the nonlinear operator */
     40:   NEP            nep;             /* nonlinear eigensolver context */
     41:   PetscBool      terse,flg;
     42:   const char*    string[NMAT]={"-K","-M","-W1","-W2"};
     43:   char           filename[PETSC_MAX_PATH_LEN];
     44:   PetscScalar    numer[2],sigma;
     45:   PetscInt       i;
     46:   PetscViewer    viewer;

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

     50:   PetscPrintf(PETSC_COMM_WORLD,"GUN problem\n\n");
     51: #if !defined(PETSC_USE_COMPLEX)
     52:   SETERRQ(PETSC_COMM_WORLD,1,"This example requires complex scalars!");
     53: #endif

     55:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     56:                        Load the problem matrices
     57:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     59:   for (i=0;i<NMAT;i++) {
     60:     PetscOptionsGetString(NULL,NULL,string[i],filename,sizeof(filename),&flg);
     61:     if (!flg) SETERRQ1(PETSC_COMM_WORLD,1,"Must indicate a filename with the %s option",string[i]);
     62:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
     63:     MatCreate(PETSC_COMM_WORLD,&A[i]);
     64:     MatSetFromOptions(A[i]);
     65:     MatLoad(A[i],viewer);
     66:     PetscViewerDestroy(&viewer);
     67:   }

     69:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     70:                        Create the problem functions
     71:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     73:   /* f1=1 */
     74:   FNCreate(PETSC_COMM_WORLD,&f[0]);
     75:   FNSetType(f[0],FNRATIONAL);
     76:   numer[0] = 1.0;
     77:   FNRationalSetNumerator(f[0],1,numer);

     79:   /* f2=-lambda */
     80:   FNCreate(PETSC_COMM_WORLD,&f[1]);
     81:   FNSetType(f[1],FNRATIONAL);
     82:   numer[0] = -1.0; numer[1] = 0.0;
     83:   FNRationalSetNumerator(f[1],2,numer);

     85:   /* f3=i*sqrt(lambda) */
     86:   FNCreate(PETSC_COMM_WORLD,&f[2]);
     87:   FNSetType(f[2],FNSQRT);
     88:   FNSetScale(f[2],1.0,PETSC_i);

     90:   /* f4=i*sqrt(lambda-sigma^2) */
     91:   sigma = SIGMA*SIGMA;
     92:   FNCreate(PETSC_COMM_WORLD,&ff[0]);
     93:   FNSetType(ff[0],FNSQRT);
     94:   FNCreate(PETSC_COMM_WORLD,&ff[1]);
     95:   FNSetType(ff[1],FNRATIONAL);
     96:   numer[0] = 1.0; numer[1] = -sigma;
     97:   FNRationalSetNumerator(ff[1],2,numer);
     98:   FNCreate(PETSC_COMM_WORLD,&f[3]);
     99:   FNSetType(f[3],FNCOMBINE);
    100:   FNCombineSetChildren(f[3],FN_COMBINE_COMPOSE,ff[1],ff[0]);
    101:   FNSetScale(f[3],1.0,PETSC_i);

    103:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    104:                 Create the eigensolver and solve the problem
    105:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    107:   NEPCreate(PETSC_COMM_WORLD,&nep);
    108:   NEPSetSplitOperator(nep,4,A,f,DIFFERENT_NONZERO_PATTERN);
    109:   NEPSetFromOptions(nep);

    111:   NEPSolve(nep);

    113:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    114:                     Display solution and clean up
    115:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    117:   /* show detailed info unless -terse option is given by user */
    118:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    119:   if (terse) {
    120:     NEPErrorView(nep,NEP_ERROR_RELATIVE,NULL);
    121:   } else {
    122:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    123:     NEPConvergedReasonView(nep,PETSC_VIEWER_STDOUT_WORLD);
    124:     NEPErrorView(nep,NEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    125:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    126:   }
    127:   NEPDestroy(&nep);
    128:   for (i=0;i<NMAT;i++) {
    129:     MatDestroy(&A[i]);
    130:     FNDestroy(&f[i]);
    131:   }
    132:   for (i=0;i<2;i++) {
    133:     FNDestroy(&ff[i]);
    134:   }
    135:   SlepcFinalize();
    136:   return ierr;
    137: }

    139: /*TEST

    141:    build:
    142:       requires: complex

    144:    test:
    145:       suffix: 1
    146:       args: -K ${DATAFILESPATH}/matrices/complex/gun_K.petsc -M ${DATAFILESPATH}/matrices/complex/gun_M.petsc -W1 ${DATAFILESPATH}/matrices/complex/gun_W1.petsc -W2 ${DATAFILESPATH}/matrices/complex/gun_W2.petsc -nep_type nleigs -rg_type polygon -rg_polygon_vertices 12500-1i,120500-1i,120500+30000i,70000+30000i -nep_target 65000 -nep_nev 24 -terse
    147:       requires: complex datafilespath !define(PETSC_USE_64BIT_INDICES)
    148:       timeoutfactor: 10

    150: TEST*/