Date: 2022-03-04T17:37:28+00:00

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*/

      9: /*
     10:   Include "petscvec.h" so that we can use vectors.  Note that this file
     11:   automatically includes:
     12:      petscsys.h       - base PETSc routines   petscis.h     - index sets
     13:      petscviewer.h - viewers
     14: */

     16: #include <petscvec.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Vec            x,y,w;               /* vectors */
     21:   Vec            *z;                    /* array of vectors */
     22:   PetscReal      norm,v,v1,v2,maxval;
     23:   PetscInt       n = 20,maxind;
     25:   PetscScalar    one = 1.0,two = 2.0,three = 3.0,dots[3],dot;

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

     30:   /*
     31:      Create a vector, specifying only its global dimension.
     32:      When using VecCreate(), VecSetSizes() and VecSetFromOptions(), the vector format
     33:      (currently parallel, shared, or sequential) is determined at runtime.  Also, the
     34:      parallel partitioning of the vector is determined by PETSc at runtime.

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

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

     47:   */
     48:   VecCreate(PETSC_COMM_WORLD,&x);
     49:   VecSetSizes(x,PETSC_DECIDE,n);
     50:   VecSetFromOptions(x);

     52:   /*
     53:      Duplicate some work vectors (of the same format and
     54:      partitioning as the initial vector).
     55:   */
     56:   VecDuplicate(x,&y);
     57:   VecDuplicate(x,&w);

     59:   /*
     60:      Duplicate more work vectors (of the same format and
     61:      partitioning as the initial vector).  Here we duplicate
     62:      an array of vectors, which is often more convenient than
     63:      duplicating individual ones.
     64:   */
     65:   VecDuplicateVecs(x,3,&z);
     66:   /*
     67:      Set the vectors to entries to a constant value.
     68:   */
     69:   VecSet(x,one);
     70:   VecSet(y,two);
     71:   VecSet(z[0],one);
     72:   VecSet(z[1],two);
     73:   VecSet(z[2],three);
     74:   /*
     75:      Demonstrate various basic vector routines.
     76:   */
     77:   VecDot(x,y,&dot);
     78:   VecMDot(x,3,z,dots);

     80:   /*
     81:      Note: If using a complex numbers version of PETSc, then
     82:      PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
     83:      (when using real numbers) it is undefined.
     84:   */

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

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

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

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

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

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

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

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

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

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

    137:   dots[0] = one;
    138:   dots[1] = three;
    139:   dots[2] = two;

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

    151:   /*
    152:      Free work space.  All PETSc objects should be destroyed when they
    153:      are no longer needed.
    154:   */
    155:   VecDestroy(&x);
    156:   VecDestroy(&y);
    157:   VecDestroy(&w);
    158:   VecDestroyVecs(3,&z);
    159:   PetscFinalize();
    160:   return ierr;
    161: }

    163: /*TEST

    165:   testset:
    166:     output_file: output/ex1_1.out
    167:     # This is a test where the exact numbers are critical
    168:     diff_args: -j

    170:     test:

    172:     test:
    173:         suffix: cuda
    174:         args: -vec_type cuda
    175:         requires: cuda

    177:     test:
    178:         suffix: kokkos
    179:         args: -vec_type kokkos
    180:         requires: kokkos_kernels

    182:     test:
    183:         suffix: hip
    184:         args: -vec_type hip
    185:         requires: hip

    187:     test:
    188:         suffix: 2
    189:         nsize: 2

    191:     test:
    192:         suffix: 2_cuda
    193:         nsize: 2
    194:         args: -vec_type cuda
    195:         requires: cuda

    197:     test:
    198:         suffix: 2_kokkos
    199:         nsize: 2
    200:         args: -vec_type kokkos
    201:         requires: kokkos_kernels

    203:     test:
    204:         suffix: 2_hip
    205:         nsize: 2
    206:         args: -vec_type hip
    207:         requires: hip

    209: TEST*/