Actual source code: ex44.c

slepc-3.17.0 2022-03-31
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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:   SlepcInitialize(&argc,&argv,(char*)0,help);

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

 36:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 37:                         Load the matrix from file
 38:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 39:     PetscPrintf(PETSC_COMM_WORLD,"\nEigenproblem stored in file.\n\n");
 40: #if defined(PETSC_USE_COMPLEX)
 41:     PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrix from a binary file...\n");
 42: #else
 43:     PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrix from a binary file...\n");
 44: #endif
 45:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
 46:     MatCreate(PETSC_COMM_WORLD,&A);
 47:     MatSetFromOptions(A);
 48:     MatLoad(A,viewer);
 49:     PetscViewerDestroy(&viewer);

 51:   } else {

 53:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 54:           Generate Brusselator matrix
 55:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 56:     PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 57:     PetscPrintf(PETSC_COMM_WORLD,"\nBrusselator wave model, n=%" PetscInt_FMT "\n\n",n);

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

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

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

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

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

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

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

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

110:   EPSSolve(eps);
111:   EPSGetType(eps,&type);
112:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
113:   EPSGetDimensions(eps,&nev,NULL,NULL);
114:   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:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
122:   if (terse) EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
123:   else {
124:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
125:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
126:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
127:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
128:   }
129:   EPSDestroy(&eps);
130:   MatDestroy(&A);
131:   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:
149:       suffix: 2_feast
150:       args: -eps_type feast -eps_interval -103,-90 -terse
151:       requires: feast !single

153: TEST*/