Date: 2018-10-23T10:32:45+00:00

Actual source code: test1.c
slepc-3.10.1 2018-10-23
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2018, 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);if (ierr) return ierr;
     49:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     50:   PetscPrintf(PETSC_COMM_WORLD,"\n1-D Nonlinear Eigenproblem, n=%D\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) {
     95:     NEPErrorView(nep,NEP_ERROR_RELATIVE,NULL);
     96:   } else {
     97:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
     98:     NEPReasonView(nep,PETSC_VIEWER_STDOUT_WORLD);
     99:     NEPErrorView(nep,NEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    100:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    101:   }

    103:   NEPDestroy(&nep);
    104:   MatDestroy(&F);
    105:   MatDestroy(&J);
    106:   SlepcFinalize();
    107:   return ierr;
    108: }

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

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

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

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

    144:   /*
    145:      Interior grid points
    146:   */
    147:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
    148:     j[0] = i-1; j[1] = i; j[2] = i+1;
    149:     A[0] = A[2] = -d-lambda*h/6.0; A[1] = 2.0*(d-lambda*h/3.0);
    150:     MatSetValues(fun,1,&i,3,j,A,INSERT_VALUES);
    151:   }

    153:   /*
    154:      Boundary points
    155:   */
    156:   if (FirstBlock) {
    157:     i = 0;
    158:     j[0] = 0; j[1] = 1;
    159:     A[0] = 2.0*(d-lambda*h/3.0); A[1] = -d-lambda*h/6.0;
    160:     MatSetValues(fun,1,&i,2,j,A,INSERT_VALUES);
    161:   }

    163:   if (LastBlock) {
    164:     i = n-1;
    165:     j[0] = n-2; j[1] = n-1;
    166:     A[0] = -d-lambda*h/6.0; A[1] = d-lambda*h/3.0+lambda*c;
    167:     MatSetValues(fun,1,&i,2,j,A,INSERT_VALUES);
    168:   }

    170:   /*
    171:      Assemble matrix
    172:   */
    173:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
    174:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
    175:   if (fun != B) {
    176:     MatAssemblyBegin(fun,MAT_FINAL_ASSEMBLY);
    177:     MatAssemblyEnd(fun,MAT_FINAL_ASSEMBLY);
    178:   }
    179:   return(0);
    180: }

    182: /* ------------------------------------------------------------------- */
    183: /*
    184:    FormJacobian - Computes Jacobian matrix  T'(lambda)

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

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

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

    215:   /*
    216:      Interior grid points
    217:   */
    218:   for (i=(FirstBlock? Istart+1: Istart);i<(LastBlock? Iend-1: Iend);i++) {
    219:     j[0] = i-1; j[1] = i; j[2] = i+1;
    220:     A[0] = A[2] = -h/6.0; A[1] = -2.0*h/3.0;
    221:     MatSetValues(jac,1,&i,3,j,A,INSERT_VALUES);
    222:   }

    224:   /*
    225:      Boundary points
    226:   */
    227:   if (FirstBlock) {
    228:     i = 0;
    229:     j[0] = 0; j[1] = 1;
    230:     A[0] = -2.0*h/3.0; A[1] = -h/6.0;
    231:     MatSetValues(jac,1,&i,2,j,A,INSERT_VALUES);
    232:   }

    234:   if (LastBlock) {
    235:     i = n-1;
    236:     j[0] = n-2; j[1] = n-1;
    237:     A[0] = -h/6.0; A[1] = -h/3.0-c*c;
    238:     MatSetValues(jac,1,&i,2,j,A,INSERT_VALUES);
    239:   }

    241:   /*
    242:      Assemble matrix
    243:   */
    244:   MatAssemblyBegin(jac,MAT_FINAL_ASSEMBLY);
    245:   MatAssemblyEnd(jac,MAT_FINAL_ASSEMBLY);
    246:   return(0);
    247: }

    249: /*TEST

    251:    test:
    252:       suffix: 1
    253:       args: -nep_type {{rii slp}} -nep_target 21 -terse
    254:       requires: !single

    256:    test:
    257:       suffix: 2_cuda
    258:       args: -nep_type {{rii slp}} -nep_target 21 -mat_type aijcusparse -terse
    259:       requires: veccuda
    260:       output_file: output/test1_1.out

    262: TEST*/