Actual source code: ex1f.F90

  1: !
  2: !
  3: !
  4: ! -----------------------------------------------------------------------

  6:       program main
  7: #include <petsc/finclude/petscvec.h>
  8:       use petscvec
  9:       implicit none

 11: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 12: !                   Variable declarations
 13: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 14: !
 15: !  Variables:
 16: !     x, y, w - vectors
 17: !     z       - array of vectors

 19:       Vec               :: x,y,w
 20:       Vec, dimension(5) :: z
 21:       PetscReal         :: norm,v,v1,v2
 22:       PetscInt, parameter :: &
 23:         ithree = 3, &
 24:         n = 20
 25:       PetscBool         :: flg
 26:       PetscErrorCode    :: ierr
 27:       PetscMPIInt       :: rank
 28:       PetscScalar, parameter :: &
 29:         one = 1.0, &
 30:         two = 2.0, &
 31:         three = 3.0
 32:       PetscScalar :: dot
 33:       PetscScalar, dimension(3) :: dots
 34:       character(len=PETSC_MAX_PATH_LEN) ::  name
 35:       PetscReal    :: nfloat

 37: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 38: !                 Beginning of program
 39: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 41:       PetscCallA(PetscInitialize(ierr))
 42:       PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr))
 43:       nfloat = n
 44:       PetscCallMPIA(MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr))

 46: !  Create a vector, specifying only its global dimension.
 47: !  When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 48: !  the vector format (currently parallel
 49: !  or sequential) is determined at runtime.  Also, the parallel
 50: !  partitioning of the vector is determined by PETSc at runtime.
 51: !
 52: !  Routines for creating particular vector types directly are:
 53: !     VecCreateSeq() - uniprocessor vector
 54: !     VecCreateMPI() - distributed vector, where the user can
 55: !                      determine the parallel partitioning
 56: !     VecCreateShared() - parallel vector that uses shared memory
 57: !                         (available only on the SGI); otherwise,
 58: !                         is the same as VecCreateMPI()
 59: !
 60: !     VecCreate(), VecSetSizes() and VecSetFromOptions() allows one
 61: !                 to determine at runtime which version to use
 62: !                 with the options -vec_type mpi or -vec_type shared
 63: !
 64:       PetscCallA(VecCreate(PETSC_COMM_WORLD,x,ierr))
 65:       PetscCallA(VecSetSizes(x,PETSC_DECIDE,n,ierr))
 66:       PetscCallA(VecSetFromOptions(x,ierr))
 67:       PetscCallA(VecGetType(x,name,ierr))

 69: !  Duplicate some work vectors (of the same format and
 70: !  partitioning as the initial vector).

 72:       PetscCallA(VecDuplicate(x,y,ierr))
 73:       PetscCallA(VecDuplicate(x,w,ierr))

 75: !  Duplicate more work vectors (of the same format and
 76: !  partitioning as the initial vector).  Here we duplicate
 77: !  an array of vectors, which is often more convenient than
 78: !  duplicating individual ones.

 80:       PetscCallA(VecDuplicateVecs(x,ithree,z,ierr))

 82: !  Set the vectors to entries to a constant value.

 84:       PetscCallA(VecSet(x,one,ierr))

 86:       PetscCallA(VecSet(y,two,ierr))
 87:       PetscCallA(VecSet(z(1),one,ierr))
 88:       PetscCallA(VecSet(z(2),two,ierr))
 89:       PetscCallA(VecSet(z(3),three,ierr))

 91: !  Demonstrate various basic vector routines.

 93:       PetscCallA(VecDot(x,x,dot,ierr))
 94:       PetscCallA(VecMDot(x,ithree,z,dots,ierr))

 96: !  Note: If using a complex numbers version of PETSc, then
 97: !  PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
 98: !  (when using real numbers) it is undefined.

100:       if (rank .eq. 0) then
101: #if defined(PETSC_USE_COMPLEX)
102:          write(6,100) int(PetscRealPart(dot))
103:          write(6,110) int(PetscRealPart(dots(1))),int(PetscRealPart(dots(2))),int(PetscRealPart(dots(3)))
104: #else
105:          write(6,100) int(dot)
106:          write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
107: #endif
108:          write(6,120)
109:       endif
110:  100  format ('Vector length ',i6)
111:  110  format ('Vector length ',3(i6))
112:  120  format ('All other values should be near zero')

114:       PetscCallA(VecScale(x,two,ierr))
115:       PetscCallA(VecNorm(x,NORM_2,norm,ierr))
116:       v = abs(norm-2.0*sqrt(nfloat))
117:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
118:       if (rank == 0) write(6,130) v
119:  130  format ('VecScale ',1pe9.2)

121:       PetscCallA(VecCopy(x,w,ierr))
122:       PetscCallA(VecNorm(w,NORM_2,norm,ierr))
123:       v = abs(norm-2.0*sqrt(nfloat))
124:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
125:       if (rank == 0) write(6,140) v
126:  140  format ('VecCopy ',1pe9.2)

128:       PetscCallA(VecAXPY(y,three,x,ierr))
129:       PetscCallA(VecNorm(y,NORM_2,norm,ierr))
130:       v = abs(norm-8.0*sqrt(nfloat))
131:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
132:       if (rank == 0) write(6,150) v
133:  150  format ('VecAXPY ',1pe9.2)

135:       PetscCallA(VecAYPX(y,two,x,ierr))
136:       PetscCallA(VecNorm(y,NORM_2,norm,ierr))
137:       v = abs(norm-18.0*sqrt(nfloat))
138:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
139:       if (rank == 0) write(6,160) v
140:  160  format ('VecAYXP ',1pe9.2)

142:       PetscCallA(VecSwap(x,y,ierr))
143:       PetscCallA(VecNorm(y,NORM_2,norm,ierr))
144:       v = abs(norm-2.0*sqrt(nfloat))
145:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
146:       if (rank == 0) write(6,170) v
147:  170  format ('VecSwap ',1pe9.2)

149:       PetscCallA(VecNorm(x,NORM_2,norm,ierr))
150:       v = abs(norm-18.0*sqrt(nfloat))
151:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
152:       if (rank == 0) write(6,180) v
153:  180  format ('VecSwap ',1pe9.2)

155:       PetscCallA(VecWAXPY(w,two,x,y,ierr))
156:       PetscCallA(VecNorm(w,NORM_2,norm,ierr))
157:       v = abs(norm-38.0*sqrt(nfloat))
158:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
159:       if (rank == 0) write(6,190) v
160:  190  format ('VecWAXPY ',1pe9.2)

162:       PetscCallA(VecPointwiseMult(w,y,x,ierr))
163:       PetscCallA(VecNorm(w,NORM_2,norm,ierr))
164:       v = abs(norm-36.0*sqrt(nfloat))
165:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
166:       if (rank == 0) write(6,200) v
167:  200  format ('VecPointwiseMult ',1pe9.2)

169:       PetscCallA(VecPointwiseDivide(w,x,y,ierr))
170:       PetscCallA(VecNorm(w,NORM_2,norm,ierr))
171:       v = abs(norm-9.0*sqrt(nfloat))
172:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
173:       if (rank == 0) write(6,210) v
174:  210  format ('VecPointwiseDivide ',1pe9.2)

176:       dots(1) = one
177:       dots(2) = three
178:       dots(3) = two
179:       PetscCallA(VecSet(x,one,ierr))
180:       PetscCallA(VecMAXPY(x,ithree,dots,z,ierr))
181:       PetscCallA(VecNorm(z(1),NORM_2,norm,ierr))
182:       v = abs(norm-sqrt(nfloat))
183:       if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
184:       PetscCallA(VecNorm(z(2),NORM_2,norm,ierr))
185:       v1 = abs(norm-2.0*sqrt(nfloat))
186:       if (v1 .gt. -PETSC_SMALL .and. v1 .lt. PETSC_SMALL) v1 = 0.0
187:       PetscCallA(VecNorm(z(3),NORM_2,norm,ierr))
188:       v2 = abs(norm-3.0*sqrt(nfloat))
189:       if (v2 .gt. -PETSC_SMALL .and. v2 .lt. PETSC_SMALL) v2 = 0.0
190:       if (rank .eq. 0) write(6,220) v,v1,v2
191:  220  format ('VecMAXPY ',3(2x,1pe9.2))

193: !  Free work space.  All PETSc objects should be destroyed when they
194: !  are no longer needed.

196:       PetscCallA(VecDestroy(x,ierr))
197:       PetscCallA(VecDestroy(y,ierr))
198:       PetscCallA(VecDestroy(w,ierr))
199:       PetscCallA(VecDestroyVecs(ithree,z,ierr))
200:       PetscCallA(PetscFinalize(ierr))

202:       end

204: !
205: !/*TEST
206: !
207: !     test:
208: !       suffix: 1
209: !
210: !     test:
211: !       suffix: 2
212: !       nsize: 2
213: !
214: !TEST*/