Actual source code: gun.c

slepc-main 2024-12-17
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-, 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: {
 36:   Mat            A[NMAT];         /* problem matrices */
 37:   FN             f[NMAT];         /* functions to define the nonlinear operator */
 38:   FN             ff[2];           /* auxiliary functions to define the nonlinear operator */
 39:   NEP            nep;             /* nonlinear eigensolver context */
 40:   PetscBool      terse,flg;
 41:   const char*    string[NMAT]={"-K","-M","-W1","-W2"};
 42:   char           filename[PETSC_MAX_PATH_LEN];
 43:   PetscScalar    numer[2],sigma;
 44:   PetscInt       i;
 45:   PetscViewer    viewer;

 47:   PetscFunctionBeginUser;
 48:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));

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

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

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

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

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

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

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

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

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

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

111:   PetscCall(NEPSolve(nep));

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

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

136: /*TEST

138:    build:
139:       requires: complex

141:    test:
142:       suffix: 1
143:       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
144:       requires: double complex datafilespath !defined(PETSC_USE_64BIT_INDICES) !defined(PETSCTEST_VALGRIND)
145:       timeoutfactor: 10

147: TEST*/