Actual source code: test1.c

slepc-3.17.2 2022-08-09
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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;

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

 53:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 54:                Prepare nonlinear eigensolver context
 55:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 57:   NEPCreate(PETSC_COMM_WORLD,&nep);

 59:   /*
 60:      Create Function and Jacobian matrices; set evaluation routines
 61:   */

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

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

 79:   NEPSetFromOptions(nep);

 81:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 82:                       Solve the eigensystem
 83:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 85:   NEPSolve(nep);

 87:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 88:                     Display solution and clean up
 89:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

108: /* ------------------------------------------------------------------- */
109: /*
110:    FormFunction - Computes Function matrix  T(lambda)

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

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

130:   /*
131:      Compute Function entries and insert into matrix
132:   */
133:   MatGetSize(fun,&n,NULL);
134:   MatGetOwnershipRange(fun,&Istart,&Iend);
135:   if (Istart==0) FirstBlock=PETSC_TRUE;
136:   if (Iend==n) LastBlock=PETSC_TRUE;
137:   h = user->h;
138:   c = user->kappa/(lambda-user->kappa);
139:   d = n;

141:   /*
142:      Interior grid points
143:   */
144:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
145:     j[0] = i-1; j[1] = i; j[2] = i+1;
146:     A[0] = A[2] = -d-lambda*h/6.0; A[1] = 2.0*(d-lambda*h/3.0);
147:     MatSetValues(fun,1,&i,3,j,A,INSERT_VALUES);
148:   }

150:   /*
151:      Boundary points
152:   */
153:   if (FirstBlock) {
154:     i = 0;
155:     j[0] = 0; j[1] = 1;
156:     A[0] = 2.0*(d-lambda*h/3.0); A[1] = -d-lambda*h/6.0;
157:     MatSetValues(fun,1,&i,2,j,A,INSERT_VALUES);
158:   }

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

167:   /*
168:      Assemble matrix
169:   */
170:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
171:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
172:   if (fun != B) {
173:     MatAssemblyBegin(fun,MAT_FINAL_ASSEMBLY);
174:     MatAssemblyEnd(fun,MAT_FINAL_ASSEMBLY);
175:   }
176:   PetscFunctionReturn(0);
177: }

179: /* ------------------------------------------------------------------- */
180: /*
181:    FormJacobian - Computes Jacobian matrix  T'(lambda)

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

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

201:   /*
202:      Compute Jacobian entries and insert into matrix
203:   */
204:   MatGetSize(jac,&n,NULL);
205:   MatGetOwnershipRange(jac,&Istart,&Iend);
206:   if (Istart==0) FirstBlock=PETSC_TRUE;
207:   if (Iend==n) LastBlock=PETSC_TRUE;
208:   h = user->h;
209:   c = user->kappa/(lambda-user->kappa);

211:   /*
212:      Interior grid points
213:   */
214:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
215:     j[0] = i-1; j[1] = i; j[2] = i+1;
216:     A[0] = A[2] = -h/6.0; A[1] = -2.0*h/3.0;
217:     MatSetValues(jac,1,&i,3,j,A,INSERT_VALUES);
218:   }

220:   /*
221:      Boundary points
222:   */
223:   if (FirstBlock) {
224:     i = 0;
225:     j[0] = 0; j[1] = 1;
226:     A[0] = -2.0*h/3.0; A[1] = -h/6.0;
227:     MatSetValues(jac,1,&i,2,j,A,INSERT_VALUES);
228:   }

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

237:   /*
238:      Assemble matrix
239:   */
240:   MatAssemblyBegin(jac,MAT_FINAL_ASSEMBLY);
241:   MatAssemblyEnd(jac,MAT_FINAL_ASSEMBLY);
242:   PetscFunctionReturn(0);
243: }

245: /*TEST

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

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

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

274: TEST*/