Actual source code: test1.c

slepc-3.18.2 2023-01-26
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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[] = "Simple 1-D nonlinear eigenproblem.\n\n"
 12:   "This is a simplified version of ex20.\n"
 13:   "The command line options are:\n"
 14:   "  -n <n>, where <n> = number of grid subdivisions.\n";

 16: /*
 17:    Solve 1-D PDE
 18:             -u'' = lambda*u
 19:    on [0,1] subject to
 20:             u(0)=0, u'(1)=u(1)*lambda*kappa/(kappa-lambda)
 21: */

 23: #include <slepcnep.h>

 25: /*
 26:    User-defined routines
 27: */
 28: PetscErrorCode FormFunction(NEP,PetscScalar,Mat,Mat,void*);
 29: PetscErrorCode FormJacobian(NEP,PetscScalar,Mat,void*);

 31: /*
 32:    User-defined application context
 33: */
 34: typedef struct {
 35:   PetscScalar kappa;   /* ratio between stiffness of spring and attached mass */
 36:   PetscReal   h;       /* mesh spacing */
 37: } ApplicationCtx;

 39: int main(int argc,char **argv)
 40: {
 41:   NEP            nep;             /* nonlinear eigensolver context */
 42:   Mat            F,J;             /* Function and Jacobian matrices */
 43:   ApplicationCtx ctx;             /* user-defined context */
 44:   PetscInt       n=128;
 45:   PetscBool      terse;

 48:   SlepcInitialize(&argc,&argv,(char*)0,help);
 49:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 50:   PetscPrintf(PETSC_COMM_WORLD,"\n1-D Nonlinear Eigenproblem, n=%" PetscInt_FMT "\n\n",n);
 51:   ctx.h = 1.0/(PetscReal)n;
 52:   ctx.kappa = 1.0;

 54:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 55:                Prepare nonlinear eigensolver context
 56:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 58:   NEPCreate(PETSC_COMM_WORLD,&nep);

 60:   /*
 61:      Create Function and Jacobian matrices; set evaluation routines
 62:   */

 64:   MatCreate(PETSC_COMM_WORLD,&F);
 65:   MatSetSizes(F,PETSC_DECIDE,PETSC_DECIDE,n,n);
 66:   MatSetFromOptions(F);
 67:   MatSeqAIJSetPreallocation(F,3,NULL);
 68:   MatMPIAIJSetPreallocation(F,3,NULL,1,NULL);
 69:   MatSetUp(F);
 70:   NEPSetFunction(nep,F,F,FormFunction,&ctx);

 72:   MatCreate(PETSC_COMM_WORLD,&J);
 73:   MatSetSizes(J,PETSC_DECIDE,PETSC_DECIDE,n,n);
 74:   MatSetFromOptions(J);
 75:   MatSeqAIJSetPreallocation(J,3,NULL);
 76:   MatMPIAIJSetPreallocation(F,3,NULL,1,NULL);
 77:   MatSetUp(J);
 78:   NEPSetJacobian(nep,J,FormJacobian,&ctx);

 80:   NEPSetFromOptions(nep);

 82:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 83:                       Solve the eigensystem
 84:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 86:   NEPSolve(nep);

 88:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 89:                     Display solution and clean up
 90:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 92:   /* show detailed info unless -terse option is given by user */
 93:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
 94:   if (terse) NEPErrorView(nep,NEP_ERROR_RELATIVE,NULL);
 95:   else {
 96:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
 97:     NEPConvergedReasonView(nep,PETSC_VIEWER_STDOUT_WORLD);
 98:     NEPErrorView(nep,NEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
 99:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
100:   }

102:   NEPDestroy(&nep);
103:   MatDestroy(&F);
104:   MatDestroy(&J);
105:   SlepcFinalize();
106:   return 0;
107: }

109: /* ------------------------------------------------------------------- */
110: /*
111:    FormFunction - Computes Function matrix  T(lambda)

113:    Input Parameters:
114: .  nep    - the NEP context
115: .  lambda - the scalar argument
116: .  ctx    - optional user-defined context, as set by NEPSetFunction()

118:    Output Parameters:
119: .  fun - Function matrix
120: .  B   - optionally different preconditioning matrix
121: */
122: PetscErrorCode FormFunction(NEP nep,PetscScalar lambda,Mat fun,Mat B,void *ctx)
123: {
124:   ApplicationCtx *user = (ApplicationCtx*)ctx;
125:   PetscScalar    A[3],c,d;
126:   PetscReal      h;
127:   PetscInt       i,n,j[3],Istart,Iend;
128:   PetscBool      FirstBlock=PETSC_FALSE,LastBlock=PETSC_FALSE;

131:   /*
132:      Compute Function entries and insert into matrix
133:   */
134:   MatGetSize(fun,&n,NULL);
135:   MatGetOwnershipRange(fun,&Istart,&Iend);
136:   if (Istart==0) FirstBlock=PETSC_TRUE;
137:   if (Iend==n) LastBlock=PETSC_TRUE;
138:   h = user->h;
139:   c = user->kappa/(lambda-user->kappa);
140:   d = n;

142:   /*
143:      Interior grid points
144:   */
145:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
146:     j[0] = i-1; j[1] = i; j[2] = i+1;
147:     A[0] = A[2] = -d-lambda*h/6.0; A[1] = 2.0*(d-lambda*h/3.0);
148:     MatSetValues(fun,1,&i,3,j,A,INSERT_VALUES);
149:   }

151:   /*
152:      Boundary points
153:   */
154:   if (FirstBlock) {
155:     i = 0;
156:     j[0] = 0; j[1] = 1;
157:     A[0] = 2.0*(d-lambda*h/3.0); A[1] = -d-lambda*h/6.0;
158:     MatSetValues(fun,1,&i,2,j,A,INSERT_VALUES);
159:   }

161:   if (LastBlock) {
162:     i = n-1;
163:     j[0] = n-2; j[1] = n-1;
164:     A[0] = -d-lambda*h/6.0; A[1] = d-lambda*h/3.0+lambda*c;
165:     MatSetValues(fun,1,&i,2,j,A,INSERT_VALUES);
166:   }

168:   /*
169:      Assemble matrix
170:   */
171:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
172:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
173:   if (fun != B) {
174:     MatAssemblyBegin(fun,MAT_FINAL_ASSEMBLY);
175:     MatAssemblyEnd(fun,MAT_FINAL_ASSEMBLY);
176:   }
177:   return 0;
178: }

180: /* ------------------------------------------------------------------- */
181: /*
182:    FormJacobian - Computes Jacobian matrix  T'(lambda)

184:    Input Parameters:
185: .  nep    - the NEP context
186: .  lambda - the scalar argument
187: .  ctx    - optional user-defined context, as set by NEPSetJacobian()

189:    Output Parameters:
190: .  jac - Jacobian matrix
191: .  B   - optionally different preconditioning matrix
192: */
193: PetscErrorCode FormJacobian(NEP nep,PetscScalar lambda,Mat jac,void *ctx)
194: {
195:   ApplicationCtx *user = (ApplicationCtx*)ctx;
196:   PetscScalar    A[3],c;
197:   PetscReal      h;
198:   PetscInt       i,n,j[3],Istart,Iend;
199:   PetscBool      FirstBlock=PETSC_FALSE,LastBlock=PETSC_FALSE;

202:   /*
203:      Compute Jacobian entries and insert into matrix
204:   */
205:   MatGetSize(jac,&n,NULL);
206:   MatGetOwnershipRange(jac,&Istart,&Iend);
207:   if (Istart==0) FirstBlock=PETSC_TRUE;
208:   if (Iend==n) LastBlock=PETSC_TRUE;
209:   h = user->h;
210:   c = user->kappa/(lambda-user->kappa);

212:   /*
213:      Interior grid points
214:   */
215:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
216:     j[0] = i-1; j[1] = i; j[2] = i+1;
217:     A[0] = A[2] = -h/6.0; A[1] = -2.0*h/3.0;
218:     MatSetValues(jac,1,&i,3,j,A,INSERT_VALUES);
219:   }

221:   /*
222:      Boundary points
223:   */
224:   if (FirstBlock) {
225:     i = 0;
226:     j[0] = 0; j[1] = 1;
227:     A[0] = -2.0*h/3.0; A[1] = -h/6.0;
228:     MatSetValues(jac,1,&i,2,j,A,INSERT_VALUES);
229:   }

231:   if (LastBlock) {
232:     i = n-1;
233:     j[0] = n-2; j[1] = n-1;
234:     A[0] = -h/6.0; A[1] = -h/3.0-c*c;
235:     MatSetValues(jac,1,&i,2,j,A,INSERT_VALUES);
236:   }

238:   /*
239:      Assemble matrix
240:   */
241:   MatAssemblyBegin(jac,MAT_FINAL_ASSEMBLY);
242:   MatAssemblyEnd(jac,MAT_FINAL_ASSEMBLY);
243:   return 0;
244: }

246: /*TEST

248:    testset:
249:       args: -nep_type {{rii slp}} -nep_target 21 -terse -nep_view_vectors ::ascii_info
250:       filter: sed -e "s/\(0x[0-9a-fA-F]*\)/objectid/" | sed -e "s/[+-]0\.0*i//g"
251:       test:
252:          suffix: 1_real
253:          requires: !single !complex
254:       test:
255:          suffix: 1
256:          requires: !single complex

258:    test:
259:       suffix: 2_cuda
260:       args: -nep_type {{rii slp}} -nep_target 21 -mat_type aijcusparse -terse
261:       requires: cuda !single
262:       filter: sed -e "s/[+-]0\.0*i//"
263:       output_file: output/test3_1.out

265:    testset:
266:       args: -nep_type slp -nep_two_sided -nep_target 21 -terse -nep_view_vectors ::ascii_info
267:       filter: sed -e "s/\(0x[0-9a-fA-F]*\)/objectid/"
268:       test:
269:          suffix: 3_real
270:          requires: !single !complex
271:       test:
272:          suffix: 3
273:          requires: !single complex

275: TEST*/