Actual source code: acoustic_wave_2d.c

slepc-3.16.1 2021-11-17
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2021, 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 acoustic_wave_2d problem is a 2-D version of acoustic_wave_1d, also
 19:    scaled for real arithmetic.
 20: */

 22: static char help[] = "Quadratic eigenproblem from an acoustics application (2-D).\n\n"
 23:   "The command line options are:\n"
 24:   "  -m <m>, where <m> = grid size, the matrices have dimension m*(m-1).\n"
 25:   "  -z <z>, where <z> = impedance (default 1.0).\n\n";

 27: #include <slepcpep.h>

 29: int main(int argc,char **argv)
 30: {
 31:   Mat            M,C,K,A[3];      /* problem matrices */
 32:   PEP            pep;             /* polynomial eigenproblem solver context */
 33:   PetscInt       m=6,n,II,Istart,Iend,i,j;
 34:   PetscScalar    z=1.0;
 35:   PetscReal      h;
 36:   char           str[50];
 37:   PetscBool      terse;

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

 42:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 43:   if (m<2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"m must be at least 2");
 44:   PetscOptionsGetScalar(NULL,NULL,"-z",&z,NULL);
 45:   h = 1.0/m;
 46:   n = m*(m-1);
 47:   SlepcSNPrintfScalar(str,sizeof(str),z,PETSC_FALSE);
 48:   PetscPrintf(PETSC_COMM_WORLD,"\nAcoustic wave 2-D, n=%D (m=%D), z=%s\n\n",n,m,str);

 50:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 51:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
 52:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 54:   /* K has a pattern similar to the 2D Laplacian */
 55:   MatCreate(PETSC_COMM_WORLD,&K);
 56:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
 57:   MatSetFromOptions(K);
 58:   MatSetUp(K);

 60:   MatGetOwnershipRange(K,&Istart,&Iend);
 61:   for (II=Istart;II<Iend;II++) {
 62:     i = II/m; j = II-i*m;
 63:     if (i>0) { MatSetValue(K,II,II-m,(j==m-1)?-0.5:-1.0,INSERT_VALUES); }
 64:     if (i<m-2) { MatSetValue(K,II,II+m,(j==m-1)?-0.5:-1.0,INSERT_VALUES); }
 65:     if (j>0) { MatSetValue(K,II,II-1,-1.0,INSERT_VALUES); }
 66:     if (j<m-1) { MatSetValue(K,II,II+1,-1.0,INSERT_VALUES); }
 67:     MatSetValue(K,II,II,(j==m-1)?2.0:4.0,INSERT_VALUES);
 68:   }

 70:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
 71:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

 73:   /* C is the zero matrix except for a few nonzero elements on the diagonal */
 74:   MatCreate(PETSC_COMM_WORLD,&C);
 75:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
 76:   MatSetFromOptions(C);
 77:   MatSetUp(C);

 79:   MatGetOwnershipRange(C,&Istart,&Iend);
 80:   for (i=Istart;i<Iend;i++) {
 81:     if (i%m==m-1) {
 82:       MatSetValue(C,i,i,-2*PETSC_PI*h/z,INSERT_VALUES);
 83:     }
 84:   }
 85:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 86:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 88:   /* M is a diagonal matrix */
 89:   MatCreate(PETSC_COMM_WORLD,&M);
 90:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
 91:   MatSetFromOptions(M);
 92:   MatSetUp(M);

 94:   MatGetOwnershipRange(M,&Istart,&Iend);
 95:   for (i=Istart;i<Iend;i++) {
 96:     if (i%m==m-1) {
 97:       MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES);
 98:     } else {
 99:       MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES);
100:     }
101:   }
102:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
103:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

105:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
106:                 Create the eigensolver and solve the problem
107:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

109:   PEPCreate(PETSC_COMM_WORLD,&pep);
110:   A[0] = K; A[1] = C; A[2] = M;
111:   PEPSetOperators(pep,3,A);
112:   PEPSetFromOptions(pep);
113:   PEPSolve(pep);

115:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116:                     Display solution and clean up
117:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

119:   /* show detailed info unless -terse option is given by user */
120:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
121:   if (terse) {
122:     PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
123:   } else {
124:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
125:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
126:     PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
127:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
128:   }
129:   PEPDestroy(&pep);
130:   MatDestroy(&M);
131:   MatDestroy(&C);
132:   MatDestroy(&K);
133:   SlepcFinalize();
134:   return ierr;
135: }

137: /*TEST

139:    testset:
140:       args: -pep_nev 2 -pep_ncv 18 -terse
141:       output_file: output/acoustic_wave_2d_1.out
142:       filter: sed -e "s/2.60936i/2.60937i/g" | sed -e "s/2.60938i/2.60937i/g"
143:       test:
144:          suffix: 1
145:          args: -pep_type {{qarnoldi linear}}
146:       test:
147:          suffix: 1_toar
148:          args: -pep_type toar -pep_toar_locking 0

150:    test:
151:       suffix: 2
152:       args: -pep_nev 2 -pep_ncv 18 -pep_type stoar -pep_hermitian -pep_scale scalar -st_type sinvert -terse

154: TEST*/