Actual source code: test6.c

slepc-3.18.0 2022-10-01
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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:    Example based on spring problem in NLEVP collection [1]. See the parameters
 12:    meaning at Example 2 in [2].

 14:    [1] T. Betcke, N. J. Higham, V. Mehrmann, C. Schroder, and F. Tisseur,
 15:        NLEVP: A Collection of Nonlinear Eigenvalue Problems, MIMS EPrint
 16:        2010.98, November 2010.
 17:    [2] F. Tisseur, Backward error and condition of polynomial eigenvalue
 18:        problems, Linear Algebra and its Applications, 309 (2000), pp. 339--361,
 19:        April 2000.
 20: */

 22: static char help[] = "Tests multiple calls to PEPSolve with different matrix of different size.\n\n"
 23:   "This is based on the spring problem from NLEVP collection.\n\n"
 24:   "The command line options are:\n"
 25:   "  -n <n> ... number of grid subdivisions.\n"
 26:   "  -mu <value> ... mass (default 1).\n"
 27:   "  -tau <value> ... damping constant of the dampers (default 10).\n"
 28:   "  -kappa <value> ... damping constant of the springs (default 5).\n"
 29:   "  -initv ... set an initial vector.\n\n";

 31: #include <slepcpep.h>

 33: int main(int argc,char **argv)
 34: {
 35:   Mat            M,C,K,A[3];      /* problem matrices */
 36:   PEP            pep;             /* polynomial eigenproblem solver context */
 37:   PetscInt       n=30,Istart,Iend,i,nev;
 38:   PetscReal      mu=1.0,tau=10.0,kappa=5.0;
 39:   PetscBool      terse=PETSC_FALSE;

 42:   SlepcInitialize(&argc,&argv,(char*)0,help);

 44:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 45:   PetscOptionsGetReal(NULL,NULL,"-mu",&mu,NULL);
 46:   PetscOptionsGetReal(NULL,NULL,"-tau",&tau,NULL);
 47:   PetscOptionsGetReal(NULL,NULL,"-kappa",&kappa,NULL);

 49:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 50:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
 51:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 53:   /* K is a tridiagonal */
 54:   MatCreate(PETSC_COMM_WORLD,&K);
 55:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
 56:   MatSetFromOptions(K);
 57:   MatSetUp(K);

 59:   MatGetOwnershipRange(K,&Istart,&Iend);
 60:   for (i=Istart;i<Iend;i++) {
 61:     if (i>0) MatSetValue(K,i,i-1,-kappa,INSERT_VALUES);
 62:     MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES);
 63:     if (i<n-1) MatSetValue(K,i,i+1,-kappa,INSERT_VALUES);
 64:   }

 66:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
 67:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

 69:   /* C is a tridiagonal */
 70:   MatCreate(PETSC_COMM_WORLD,&C);
 71:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
 72:   MatSetFromOptions(C);
 73:   MatSetUp(C);

 75:   MatGetOwnershipRange(C,&Istart,&Iend);
 76:   for (i=Istart;i<Iend;i++) {
 77:     if (i>0) MatSetValue(C,i,i-1,-tau,INSERT_VALUES);
 78:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
 79:     if (i<n-1) MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
 80:   }

 82:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 83:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 85:   /* M is a diagonal matrix */
 86:   MatCreate(PETSC_COMM_WORLD,&M);
 87:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
 88:   MatSetFromOptions(M);
 89:   MatSetUp(M);
 90:   MatGetOwnershipRange(M,&Istart,&Iend);
 91:   for (i=Istart;i<Iend;i++) MatSetValue(M,i,i,mu,INSERT_VALUES);
 92:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
 93:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

 95:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 96:                 Create the eigensolver and set various options
 97:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 99:   PEPCreate(PETSC_COMM_WORLD,&pep);
100:   A[0] = K; A[1] = C; A[2] = M;
101:   PEPSetOperators(pep,3,A);
102:   PEPSetProblemType(pep,PEP_GENERAL);
103:   PEPSetTolerances(pep,PETSC_SMALL,PETSC_DEFAULT);
104:   PEPSetFromOptions(pep);

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

110:   PEPSolve(pep);
111:   PEPGetDimensions(pep,&nev,NULL,NULL);
112:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);

114:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
115:                       Display solution of first solve
116:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
117:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
118:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
119:   else {
120:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
121:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
122:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
123:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
124:   }
125:   MatDestroy(&M);
126:   MatDestroy(&C);
127:   MatDestroy(&K);

129:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
130:      Compute the eigensystem, (k^2*M+k*C+K)x=0 for bigger n
131:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

133:   n *= 2;
134:   /* K is a tridiagonal */
135:   MatCreate(PETSC_COMM_WORLD,&K);
136:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
137:   MatSetFromOptions(K);
138:   MatSetUp(K);

140:   MatGetOwnershipRange(K,&Istart,&Iend);
141:   for (i=Istart;i<Iend;i++) {
142:     if (i>0) MatSetValue(K,i,i-1,-kappa,INSERT_VALUES);
143:     MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES);
144:     if (i<n-1) MatSetValue(K,i,i+1,-kappa,INSERT_VALUES);
145:   }

147:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
148:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

150:   /* C is a tridiagonal */
151:   MatCreate(PETSC_COMM_WORLD,&C);
152:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
153:   MatSetFromOptions(C);
154:   MatSetUp(C);

156:   MatGetOwnershipRange(C,&Istart,&Iend);
157:   for (i=Istart;i<Iend;i++) {
158:     if (i>0) MatSetValue(C,i,i-1,-tau,INSERT_VALUES);
159:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
160:     if (i<n-1) MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
161:   }

163:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
164:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

166:   /* M is a diagonal matrix */
167:   MatCreate(PETSC_COMM_WORLD,&M);
168:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
169:   MatSetFromOptions(M);
170:   MatSetUp(M);
171:   MatGetOwnershipRange(M,&Istart,&Iend);
172:   for (i=Istart;i<Iend;i++) MatSetValue(M,i,i,mu,INSERT_VALUES);
173:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
174:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

176:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
177:        Solve again, calling PEPReset() since matrix size has changed
178:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
179:   /* PEPReset(pep); */  /* not required, will be called in PEPSetOperators() */
180:   A[0] = K; A[1] = C; A[2] = M;
181:   PEPSetOperators(pep,3,A);
182:   PEPSolve(pep);

184:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
185:                     Display solution and clean up
186:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
187:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
188:   else {
189:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
190:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
191:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
192:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
193:   }
194:   PEPDestroy(&pep);
195:   MatDestroy(&M);
196:   MatDestroy(&C);
197:   MatDestroy(&K);
198:   SlepcFinalize();
199:   return 0;
200: }

202: /*TEST

204:    test:
205:       suffix: 1
206:       args: -pep_type {{toar qarnoldi linear}} -pep_nev 4 -terse
207:       requires: double

209:    test:
210:       suffix: 2
211:       args: -pep_type stoar -pep_hermitian -pep_nev 4 -terse
212:       requires: !single

214: TEST*/