Actual source code: ex44.c

slepc-3.22.1 2024-10-28
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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: */

 11: static char help[] = "Compute rightmost eigenvalues with Lyapunov inverse iteration.\n\n"
 12:   "Loads matrix from a file or builds the same problem as ex36.c (with fixed parameters).\n\n"
 13:   "The command line options are:\n"
 14:   "  -file <filename>, where <filename> = matrix file in PETSc binary form.\n"
 15:   "  -shift <sigma>, shift to make the matrix stable.\n"
 16:   "  -n <n>, block dimension of the 2x2 block matrix (if matrix is generated).\n\n";

 18: #include <slepceps.h>

 20: int main(int argc,char **argv)
 21: {
 22:   Mat            A;               /* operator matrix */
 23:   EPS            eps;             /* eigenproblem solver context */
 24:   EPSType        type;
 25:   PetscScalar    alpha,beta,tau1,tau2,delta1,delta2,L,h,sigma=0.0;
 26:   PetscInt       n=30,i,Istart,Iend,nev;
 27:   char           filename[PETSC_MAX_PATH_LEN];
 28:   PetscViewer    viewer;
 29:   PetscBool      flg,terse;

 31:   PetscFunctionBeginUser;
 32:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));

 34:   PetscCall(PetscOptionsGetString(NULL,NULL,"-file",filename,sizeof(filename),&flg));
 35:   if (flg) {

 37:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 38:                         Load the matrix from file
 39:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 40:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nEigenproblem stored in file.\n\n"));
 41: #if defined(PETSC_USE_COMPLEX)
 42:     PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrix from a binary file...\n"));
 43: #else
 44:     PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrix from a binary file...\n"));
 45: #endif
 46:     PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer));
 47:     PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
 48:     PetscCall(MatSetFromOptions(A));
 49:     PetscCall(MatLoad(A,viewer));
 50:     PetscCall(PetscViewerDestroy(&viewer));

 52:   } else {

 54:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 55:           Generate Brusselator matrix
 56:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 57:     PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 58:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nBrusselator wave model, n=%" PetscInt_FMT "\n\n",n));

 60:     alpha  = 2.0;
 61:     beta   = 5.45;
 62:     delta1 = 0.008;
 63:     delta2 = 0.004;
 64:     L      = 0.51302;

 66:     h = 1.0 / (PetscReal)(n+1);
 67:     tau1 = delta1 / ((h*L)*(h*L));
 68:     tau2 = delta2 / ((h*L)*(h*L));

 70:     PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
 71:     PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,2*n,2*n));
 72:     PetscCall(MatSetFromOptions(A));

 74:     PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
 75:     for (i=Istart;i<Iend;i++) {
 76:       if (i<n) {  /* upper blocks */
 77:         if (i>0) PetscCall(MatSetValue(A,i,i-1,tau1,INSERT_VALUES));
 78:         if (i<n-1) PetscCall(MatSetValue(A,i,i+1,tau1,INSERT_VALUES));
 79:         PetscCall(MatSetValue(A,i,i,-2.0*tau1+beta-1.0,INSERT_VALUES));
 80:         PetscCall(MatSetValue(A,i,i+n,alpha*alpha,INSERT_VALUES));
 81:       } else {  /* lower blocks */
 82:         if (i>n) PetscCall(MatSetValue(A,i,i-1,tau2,INSERT_VALUES));
 83:         if (i<2*n-1) PetscCall(MatSetValue(A,i,i+1,tau2,INSERT_VALUES));
 84:         PetscCall(MatSetValue(A,i,i,-2.0*tau2-alpha*alpha,INSERT_VALUES));
 85:         PetscCall(MatSetValue(A,i,i-n,-beta,INSERT_VALUES));
 86:       }
 87:     }
 88:     PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
 89:     PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
 90:   }

 92:   /* Shift the matrix to make it stable, A-sigma*I */
 93:   PetscCall(PetscOptionsGetScalar(NULL,NULL,"-shift",&sigma,NULL));
 94:   PetscCall(MatShift(A,-sigma));

 96:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 97:                 Create the eigensolver and set various options
 98:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

100:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
101:   PetscCall(EPSSetOperators(eps,A,NULL));
102:   PetscCall(EPSSetProblemType(eps,EPS_NHEP));
103:   PetscCall(EPSSetWhichEigenpairs(eps,EPS_LARGEST_REAL));
104:   PetscCall(EPSSetFromOptions(eps));

106:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
107:                       Solve the eigensystem
108:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

110:   PetscCall(EPSSolve(eps));
111:   PetscCall(EPSGetType(eps,&type));
112:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type));
113:   PetscCall(EPSGetDimensions(eps,&nev,NULL,NULL));
114:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev));

116:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
117:                     Display solution and clean up
118:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

120:   /* show detailed info unless -terse option is given by user */
121:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
122:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
123:   else {
124:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
125:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
126:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
127:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
128:   }
129:   PetscCall(EPSDestroy(&eps));
130:   PetscCall(MatDestroy(&A));
131:   PetscCall(SlepcFinalize());
132:   return 0;
133: }

135: /*TEST

137:    testset:
138:       args: -eps_nev 6 -shift 0.1 -eps_type {{krylovschur lyapii}} -eps_tol 1e-7 -terse
139:       requires: double
140:       filter: grep -v method | sed -e "s/-0.09981-2.13938i, -0.09981+2.13938i/-0.09981+2.13938i, -0.09981-2.13938i/" | sed -e "s/-0.77192-2.52712i, -0.77192+2.52712i/-0.77192+2.52712i, -0.77192-2.52712i/" | sed -e "s/-1.88445-3.02666i, -1.88445+3.02666i/-1.88445+3.02666i, -1.88445-3.02666i/"
141:       output_file: output/ex44_1.out
142:       test:
143:          suffix: 1
144:       test:
145:          suffix: 2
146:          args: -eps_lyapii_ranks 8,20 -options_left no

148: TEST*/