Date: 2026-03-31T13:23:19+00:00

Actual source code: test4.c

      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[] = "Test ST with four matrices.\n\n";

     13: #include <slepcst.h>

     15: int main(int argc,char **argv)
     16: {
     17:   Mat            A,B,C,D,mat[4];
     18:   ST             st;
     19:   KSP            ksp;
     20:   Vec            v,w;
     21:   STType         type;
     22:   PetscScalar    sigma;
     23:   PetscInt       n=10,i,Istart,Iend;

     25:   PetscFunctionBeginUser;
     26:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
     27:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     28:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nTest ST with four matrices, n=%" PetscInt_FMT "\n\n",n));
     29:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     30:      Compute the operator matrices
     31:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     33:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     34:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n));
     35:   PetscCall(MatSetFromOptions(A));

     37:   PetscCall(MatCreate(PETSC_COMM_WORLD,&B));
     38:   PetscCall(MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,n,n));
     39:   PetscCall(MatSetFromOptions(B));

     41:   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
     42:   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
     43:   PetscCall(MatSetFromOptions(C));

     45:   PetscCall(MatCreate(PETSC_COMM_WORLD,&D));
     46:   PetscCall(MatSetSizes(D,PETSC_DECIDE,PETSC_DECIDE,n,n));
     47:   PetscCall(MatSetFromOptions(D));

     49:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
     50:   for (i=Istart;i<Iend;i++) {
     51:     PetscCall(MatSetValue(A,i,i,2.0,INSERT_VALUES));
     52:     if (i>0) {
     53:       PetscCall(MatSetValue(A,i,i-1,-1.0,INSERT_VALUES));
     54:       PetscCall(MatSetValue(B,i,i,(PetscScalar)i,INSERT_VALUES));
     55:     } else PetscCall(MatSetValue(B,i,i,-1.0,INSERT_VALUES));
     56:     if (i<n-1) PetscCall(MatSetValue(A,i,i+1,-1.0,INSERT_VALUES));
     57:     PetscCall(MatSetValue(C,i,n-i-1,1.0,INSERT_VALUES));
     58:     PetscCall(MatSetValue(D,i,i,i*.1,INSERT_VALUES));
     59:     if (i==0) PetscCall(MatSetValue(D,0,n-1,1.0,INSERT_VALUES));
     60:     if (i==n-1) PetscCall(MatSetValue(D,n-1,0,1.0,INSERT_VALUES));
     61:   }

     63:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
     64:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
     65:   PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
     66:   PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY));
     67:   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
     68:   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
     69:   PetscCall(MatAssemblyBegin(D,MAT_FINAL_ASSEMBLY));
     70:   PetscCall(MatAssemblyEnd(D,MAT_FINAL_ASSEMBLY));
     71:   PetscCall(MatCreateVecs(A,&v,&w));
     72:   PetscCall(VecSet(v,1.0));

     74:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     75:                 Create the spectral transformation object
     76:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     78:   PetscCall(STCreate(PETSC_COMM_WORLD,&st));
     79:   mat[0] = A;
     80:   mat[1] = B;
     81:   mat[2] = C;
     82:   mat[3] = D;
     83:   PetscCall(STSetMatrices(st,4,mat));
     84:   PetscCall(STGetKSP(st,&ksp));
     85:   PetscCall(KSPSetTolerances(ksp,100*PETSC_MACHINE_EPSILON,PETSC_CURRENT,PETSC_CURRENT,PETSC_CURRENT));
     86:   PetscCall(STSetFromOptions(st));

     88:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     89:               Apply the transformed operator for several ST's
     90:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     92:   /* shift, sigma=0.0 */
     93:   PetscCall(STSetUp(st));
     94:   PetscCall(STGetType(st,&type));
     95:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"ST type %s\n",type));
     96:   for (i=0;i<4;i++) {
     97:     PetscCall(STMatMult(st,i,v,w));
     98:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"k= %" PetscInt_FMT "\n",i));
     99:     PetscCall(VecView(w,NULL));
    100:   }
    101:   PetscCall(STMatSolve(st,v,w));
    102:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"solve\n"));
    103:   PetscCall(VecView(w,NULL));

    105:   /* shift, sigma=0.1 */
    106:   sigma = 0.1;
    107:   PetscCall(STSetShift(st,sigma));
    108:   PetscCall(STGetShift(st,&sigma));
    109:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma)));
    110:   for (i=0;i<4;i++) {
    111:     PetscCall(STMatMult(st,i,v,w));
    112:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"k= %" PetscInt_FMT "\n",i));
    113:     PetscCall(VecView(w,NULL));
    114:   }
    115:   PetscCall(STMatSolve(st,v,w));
    116:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"solve\n"));
    117:   PetscCall(VecView(w,NULL));

    119:   /* sinvert, sigma=0.1 */
    120:   PetscCall(STPostSolve(st));
    121:   PetscCall(STSetType(st,STSINVERT));
    122:   PetscCall(STGetType(st,&type));
    123:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"ST type %s\n",type));
    124:   PetscCall(STGetShift(st,&sigma));
    125:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma)));
    126:   for (i=0;i<4;i++) {
    127:     PetscCall(STMatMult(st,i,v,w));
    128:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"k= %" PetscInt_FMT "\n",i));
    129:     PetscCall(VecView(w,NULL));
    130:   }
    131:   PetscCall(STMatSolve(st,v,w));
    132:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"solve\n"));
    133:   PetscCall(VecView(w,NULL));

    135:   /* sinvert, sigma=-0.5 */
    136:   sigma = -0.5;
    137:   PetscCall(STSetShift(st,sigma));
    138:   PetscCall(STGetShift(st,&sigma));
    139:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma)));
    140:   for (i=0;i<4;i++) {
    141:     PetscCall(STMatMult(st,i,v,w));
    142:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"k= %" PetscInt_FMT "\n",i));
    143:     PetscCall(VecView(w,NULL));
    144:   }
    145:   PetscCall(STMatSolve(st,v,w));
    146:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"solve\n"));
    147:   PetscCall(VecView(w,NULL));

    149:   PetscCall(STDestroy(&st));
    150:   PetscCall(MatDestroy(&A));
    151:   PetscCall(MatDestroy(&B));
    152:   PetscCall(MatDestroy(&C));
    153:   PetscCall(MatDestroy(&D));
    154:   PetscCall(VecDestroy(&v));
    155:   PetscCall(VecDestroy(&w));
    156:   PetscCall(SlepcFinalize());
    157:   return 0;
    158: }

    160: /*TEST

    162:    test:
    163:       suffix: 1
    164:       args: -st_transform -st_matmode {{copy shell}}
    165:       requires: !single

    167:    test:
    168:       suffix: 2
    169:       args: -st_matmode {{copy shell}}

    171: TEST*/