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;
 24:   PetscScalar    one = 1.0,two = 2.0,three = 3.0,dots[3],dot;

 26:   PetscInitialize(&argc,&argv,(char*)0,help);
 27:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);

 29:   /*
 30:      Create a vector, specifying only its global dimension.
 31:      When using VecCreate(), VecSetSizes() and VecSetFromOptions(), the vector format
 32:      (currently parallel, shared, or sequential) is determined at runtime.  Also, the
 33:      parallel partitioning of the vector is determined by PETSc at runtime.

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

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

 46:   */
 47:   VecCreate(PETSC_COMM_WORLD,&x);
 48:   VecSetSizes(x,PETSC_DECIDE,n);
 49:   VecSetFromOptions(x);

 51:   /*
 52:      Duplicate some work vectors (of the same format and
 53:      partitioning as the initial vector).
 54:   */
 55:   VecDuplicate(x,&y);
 56:   VecDuplicate(x,&w);

 58:   /*
 59:      Duplicate more work vectors (of the same format and
 60:      partitioning as the initial vector).  Here we duplicate
 61:      an array of vectors, which is often more convenient than
 62:      duplicating individual ones.
 63:   */
 64:   VecDuplicateVecs(x,3,&z);
 65:   /*
 66:      Set the vectors to entries to a constant value.
 67:   */
 68:   VecSet(x,one);
 69:   VecSet(y,two);
 70:   VecSet(z[0],one);
 71:   VecSet(z[1],two);
 72:   VecSet(z[2],three);
 73:   /*
 74:      Demonstrate various basic vector routines.
 75:   */
 76:   VecDot(x,y,&dot);
 77:   VecMDot(x,3,z,dots);

 79:   /*
 80:      Note: If using a complex numbers version of PETSc, then
 81:      PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
 82:      (when using real numbers) it is undefined.
 83:   */

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

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

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

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

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

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

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

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

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

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

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

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

150:   /*
151:      Free work space.  All PETSc objects should be destroyed when they
152:      are no longer needed.
153:   */
154:   VecDestroy(&x);
155:   VecDestroy(&y);
156:   VecDestroy(&w);
157:   VecDestroyVecs(3,&z);
158:   PetscFinalize();
159:   return 0;
160: }

162: /*TEST

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

169:     test:

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

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

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

186:     test:
187:         suffix: 2
188:         nsize: 2

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

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

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

208: TEST*/