Actual source code: ex1.c

      2: static char help[] = "Basic vector routines.\n\n";

      4: /*T
      5:    Concepts: vectors^basic routines;
      6:    Processors: n
      7: T*/

     11: /*
     12:   Include "petscvec.h" so that we can use vectors.  Note that this file
     13:   automatically includes:
     14:      petscsys.h       - base PETSc routines   petscis.h     - index sets
     15:      petscviewer.h - viewers
     16: */

     18: #include <petscvec.h>

     20: int main(int argc,char **argv)
     21: {
     22:   Vec            x,y,w;               /* vectors */
     23:   Vec            *z;                    /* array of vectors */
     24:   PetscReal      norm,v,v1,v2,maxval;
     25:   PetscInt       n = 20,maxind;
     27:   PetscScalar    one = 1.0,two = 2.0,three = 3.0,dots[3],dot;

     29:   PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
     30:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);

     32:   /*
     33:      Create a vector, specifying only its global dimension.
     34:      When using VecCreate(), VecSetSizes() and VecSetFromOptions(), the vector format
     35:      (currently parallel, shared, or sequential) is determined at runtime.  Also, the
     36:      parallel partitioning of the vector is determined by PETSc at runtime.

     38:      Routines for creating particular vector types directly are:
     39:         VecCreateSeq() - uniprocessor vector
     40:         VecCreateMPI() - distributed vector, where the user can
     41:                          determine the parallel partitioning
     42:         VecCreateShared() - parallel vector that uses shared memory
     43:                             (available only on the SGI); otherwise,
     44:                             is the same as VecCreateMPI()

     46:      With VecCreate(), VecSetSizes() and VecSetFromOptions() the option -vec_type mpi or
     47:      -vec_type shared causes the particular type of vector to be formed.

     49:   */
     50:   VecCreate(PETSC_COMM_WORLD,&x);
     51:   VecSetSizes(x,PETSC_DECIDE,n);
     52:   VecSetFromOptions(x);

     54:   /*
     55:      Duplicate some work vectors (of the same format and
     56:      partitioning as the initial vector).
     57:   */
     58:   VecDuplicate(x,&y);
     59:   VecDuplicate(x,&w);

     61:   /*
     62:      Duplicate more work vectors (of the same format and
     63:      partitioning as the initial vector).  Here we duplicate
     64:      an array of vectors, which is often more convenient than
     65:      duplicating individual ones.
     66:   */
     67:   VecDuplicateVecs(x,3,&z);
     68:   /*
     69:      Set the vectors to entries to a constant value.
     70:   */
     71:   VecSet(x,one);
     72:   VecSet(y,two);
     73:   VecSet(z[0],one);
     74:   VecSet(z[1],two);
     75:   VecSet(z[2],three);
     76:   /*
     77:      Demonstrate various basic vector routines.
     78:   */
     79:   VecDot(x,y,&dot);
     80:   VecMDot(x,3,z,dots);

     82:   /*
     83:      Note: If using a complex numbers version of PETSc, then
     84:      PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
     85:      (when using real numbers) it is undefined.
     86:   */

     88:   PetscPrintf(PETSC_COMM_WORLD,"Vector length %D\n",n);
     89:   VecMax(x,&maxind,&maxval);
     90:   PetscPrintf(PETSC_COMM_WORLD,"VecMax %g, VecInd %D\n",(double)maxval,maxind);

     92:   VecMin(x,&maxind,&maxval);
     93:   PetscPrintf(PETSC_COMM_WORLD,"VecMin %g, VecInd %D\n",(double)maxval,maxind);
     94:   PetscPrintf(PETSC_COMM_WORLD,"All other values should be near zero\n");

     97:   VecScale(x,two);
     98:   VecNorm(x,NORM_2,&norm);
     99:   v    = norm-2.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    100:   PetscPrintf(PETSC_COMM_WORLD,"VecScale %g\n",(double)v);

    103:   VecCopy(x,w);
    104:   VecNorm(w,NORM_2,&norm);
    105:   v    = norm-2.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    106:   PetscPrintf(PETSC_COMM_WORLD,"VecCopy  %g\n",(double)v);

    108:   VecAXPY(y,three,x);
    109:   VecNorm(y,NORM_2,&norm);
    110:   v    = norm-8.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    111:   PetscPrintf(PETSC_COMM_WORLD,"VecAXPY %g\n",(double)v);

    113:   VecAYPX(y,two,x);
    114:   VecNorm(y,NORM_2,&norm);
    115:   v    = norm-18.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    116:   PetscPrintf(PETSC_COMM_WORLD,"VecAYPX %g\n",(double)v);

    118:   VecSwap(x,y);
    119:   VecNorm(y,NORM_2,&norm);
    120:   v    = norm-2.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    121:   PetscPrintf(PETSC_COMM_WORLD,"VecSwap  %g\n",(double)v);
    122:   VecNorm(x,NORM_2,&norm);
    123:   v = norm-18.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    124:   PetscPrintf(PETSC_COMM_WORLD,"VecSwap  %g\n",(double)v);

    126:   VecWAXPY(w,two,x,y);
    127:   VecNorm(w,NORM_2,&norm);
    128:   v    = norm-38.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    129:   PetscPrintf(PETSC_COMM_WORLD,"VecWAXPY %g\n",(double)v);

    131:   VecPointwiseMult(w,y,x);
    132:   VecNorm(w,NORM_2,&norm);
    133:   v    = norm-36.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    134:   PetscPrintf(PETSC_COMM_WORLD,"VecPointwiseMult %g\n",(double)v);

    136:   VecPointwiseDivide(w,x,y);
    137:   VecNorm(w,NORM_2,&norm);
    138:   v    = norm-9.0*PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    139:   PetscPrintf(PETSC_COMM_WORLD,"VecPointwiseDivide %g\n",(double)v);

    141:   dots[0] = one;
    142:   dots[1] = three;
    143:   dots[2] = two;

    145:   VecSet(x,one);
    146:   VecMAXPY(x,3,dots,z);
    147:   VecNorm(z[0],NORM_2,&norm);
    148:   v    = norm-PetscSqrtReal((PetscReal)n); if (v > -PETSC_SMALL && v < PETSC_SMALL) v = 0.0;
    149:   VecNorm(z[1],NORM_2,&norm);
    150:   v1   = norm-2.0*PetscSqrtReal((PetscReal)n); if (v1 > -PETSC_SMALL && v1 < PETSC_SMALL) v1 = 0.0;
    151:   VecNorm(z[2],NORM_2,&norm);
    152:   v2   = norm-3.0*PetscSqrtReal((PetscReal)n); if (v2 > -PETSC_SMALL && v2 < PETSC_SMALL) v2 = 0.0;
    153:   PetscPrintf(PETSC_COMM_WORLD,"VecMAXPY %g %g %g \n",(double)v,(double)v1,(double)v2);

    155:   /*
    156:      Free work space.  All PETSc objects should be destroyed when they
    157:      are no longer needed.
    158:   */
    159:   VecDestroy(&x);
    160:   VecDestroy(&y);
    161:   VecDestroy(&w);
    162:   VecDestroyVecs(3,&z);
    163:   PetscFinalize();
    164:   return ierr;
    165: }

    167: /*TEST

    169:   testset:
    170:     output_file: output/ex1_1.out
    171:     # This is a test where the exact numbers are critical
    172:     diff_args: -j

    174:     test:

    176:     test:
    177:         suffix: cuda
    178:         args: -vec_type cuda
    179:         requires: cuda

    181:     test:
    182:         suffix: kokkos
    183:         args: -vec_type kokkos
    184:         requires: kokkos_kernels

    186:     test:
    187:         suffix: hip
    188:         args: -vec_type hip
    189:         requires: hip

    191:     test:
    192:         suffix: 2
    193:         nsize: 2

    195:     test:
    196:         suffix: 2_cuda
    197:         nsize: 2
    198:         args: -vec_type cuda
    199:         requires: cuda

    201:     test:
    202:         suffix: 2_kokkos
    203:         nsize: 2
    204:         args: -vec_type kokkos
    205:         requires: kokkos_kernels

    207:     test:
    208:         suffix: 2_hip
    209:         nsize: 2
    210:         args: -vec_type hip
    211:         requires: hip

    213: TEST*/