Actual source code: ex20f90.F90

petsc-master 2016-08-29
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  1: !
  2: !
  3: !/*T
  4: !   Concepts: vectors^using basic vector routines;
  5: !   Concepts: Fortran90^using basic vector routines;
  6: !   Processors: n
  7: !T*/
  8: !
  9: ! -----------------------------------------------------------------------

 11:       program main

 13: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 14: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 15: !
 16: !
 17: !     This examples uses Fortran 90 MODULES instead of include files
 18: !   see the manual page UsingFortran
 19: !
 20: #define PETSC_USE_FORTRAN_MODULES
 21:  #include <petsc/finclude/petscsysdef.h>
 22:  #include <petsc/finclude/petscvecdef.h>
 23: #if defined(PETSC_USE_FORTRAN_MODULES)
 24:       use petscvec
 25: #endif
 26:       implicit none
 27: #if !defined(PETSC_USE_FORTRAN_MODULES)
 28:  #include <petsc/finclude/petscsys.h>
 29:  #include <petsc/finclude/petscvec.h>
 30: #include <petsc/finclude/petscvec.h90>

 32: #endif
 33: !
 34: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 35: !                   Variable declarations
 36: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 37: !
 38: !  Variables:
 39: !     x, y, w - vectors
 40: !     z       - array of vectors
 41: !
 42: #if defined(PETSC_USE_FORTRAN_DATATYPES)
 43:       type(Vec)       x,y,w
 44:       type(Vec), pointer :: z(:)
 45: #else
 46:       Vec              x,y,w
 47:       Vec, pointer :: z(:)
 48: #endif
 49:       PetscReal norm,v,v1,v2
 50:       PetscInt  n,ithree
 51:       PetscErrorCode ierr
 52:       PetscMPIInt  rank
 53:       PetscBool       flg
 54:       PetscScalar      one,two,three
 55:       PetscScalar      dots(3),dot
 56:       PetscReal        nfloat

 58: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 59: !                 Beginning of program
 60: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 62:       call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
 63:       one   = 1.0
 64:       two   = 2.0
 65:       three = 3.0
 66:       n     = 20
 67:       ithree = 3

 69:       call PetscOptionsGetInt(PETSC_NULL_OBJECT,PETSC_NULL_CHARACTER,         &
 70:      &                        '-n',n,flg,ierr)
 71:       nfloat = n
 72:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)

 74: !  Create a vector, specifying only its global dimension.
 75: !  When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 76: !  the vector format (currently parallel
 77: !  or sequential) is determined at runtime.  Also, the parallel
 78: !  partitioning of the vector is determined by PETSc at runtime.
 79: !
 80: !  Routines for creating particular vector types directly are:
 81: !     VecCreateSeq() - uniprocessor vector
 82: !     VecCreateMPI() - distributed vector, where the user can
 83: !                      determine the parallel partitioning

 85:       call VecCreate(PETSC_COMM_WORLD,x,ierr)
 86:       call VecSetSizes(x,PETSC_DECIDE,n,ierr)
 87:       call VecSetFromOptions(x,ierr)

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

 92:       call VecDuplicate(x,y,ierr)
 93:       call VecDuplicate(x,w,ierr)

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

100:       call VecDuplicateVecsF90(x,ithree,z,ierr)

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

104:       call VecSet(x,one,ierr)
105:       call VecSet(y,two,ierr)
106:       call VecSet(z(1),one,ierr)
107:       call VecSet(z(2),two,ierr)
108:       call VecSet(z(3),three,ierr)

110: !  Demonstrate various basic vector routines.

112:       call VecDot(x,x,dot,ierr)
113:       call VecMDot(x,ithree,z,dots,ierr)

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

119:       if (rank .eq. 0) then
120: #if defined(PETSC_USE_COMPLEX)
121:          write(6,100) int(PetscRealPart(dot))
122:          write(6,110) int(PetscRealPart(dots(1))),                               &
123:      &                int(PetscRealPart(dots(2))),                               &
124:      &                int(PetscRealPart(dots(3)))
125: #else
126:          write(6,100) int(dot)
127:          write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
128: #endif
129:          write(6,120)
130:       endif
131:  100  format ('Vector length ',i6)
132:  110  format ('Vector length ',3(i6))
133:  120  format ('All other values should be near zero')

135:       call VecScale(x,two,ierr)
136:       call VecNorm(x,NORM_2,norm,ierr)
137:       v = abs(norm-2.0*sqrt(nfloat))
138:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
139:       if (rank .eq. 0) write(6,130) v
140:  130  format ('VecScale ',1pe8.2)

142:       call VecCopy(x,w,ierr)
143:       call VecNorm(w,NORM_2,norm,ierr)
144:       v = abs(norm-2.0*sqrt(nfloat))
145:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
146:       if (rank .eq. 0) write(6,140) v
147:  140  format ('VecCopy ',1pe8.2)

149:       call VecAXPY(y,three,x,ierr)
150:       call VecNorm(y,NORM_2,norm,ierr)
151:       v = abs(norm-8.0*sqrt(nfloat))
152:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
153:       if (rank .eq. 0) write(6,150) v
154:  150  format ('VecAXPY ',1pe8.2)

156:       call VecAYPX(y,two,x,ierr)
157:       call VecNorm(y,NORM_2,norm,ierr)
158:       v = abs(norm-18.0*sqrt(nfloat))
159:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
160:       if (rank .eq. 0) write(6,160) v
161:  160  format ('VecAYXP ',1pe8.2)

163:       call VecSwap(x,y,ierr)
164:       call VecNorm(y,NORM_2,norm,ierr)
165:       v = abs(norm-2.0*sqrt(nfloat))
166:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
167:       if (rank .eq. 0) write(6,170) v
168:  170  format ('VecSwap ',1pe8.2)

170:       call VecNorm(x,NORM_2,norm,ierr)
171:       v = abs(norm-18.0*sqrt(nfloat))
172:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
173:       if (rank .eq. 0) write(6,180) v
174:  180  format ('VecSwap ',1pe8.2)

176:       call VecWAXPY(w,two,x,y,ierr)
177:       call VecNorm(w,NORM_2,norm,ierr)
178:       v = abs(norm-38.0*sqrt(nfloat))
179:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
180:       if (rank .eq. 0) write(6,190) v
181:  190  format ('VecWAXPY ',1pe8.2)

183:       call VecPointwiseMult(w,y,x,ierr)
184:       call VecNorm(w,NORM_2,norm,ierr)
185:       v = abs(norm-36.0*sqrt(nfloat))
186:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
187:       if (rank .eq. 0) write(6,200) v
188:  200  format ('VecPointwiseMult ',1pe8.2)

190:       call VecPointwiseDivide(w,x,y,ierr)
191:       call VecNorm(w,NORM_2,norm,ierr)
192:       v = abs(norm-9.0*sqrt(nfloat))
193:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
194:       if (rank .eq. 0) write(6,210) v
195:  210  format ('VecPointwiseDivide ',1pe8.2)


198:       dots(1) = one
199:       dots(2) = three
200:       dots(3) = two
201:       call VecSet(x,one,ierr)
202:       call VecMAXPY(x,ithree,dots,z,ierr)
203:       call VecNorm(z(1),NORM_2,norm,ierr)
204:       v = abs(norm-sqrt(nfloat))
205:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
206:       call VecNorm(z(2),NORM_2,norm,ierr)
207:       v1 = abs(norm-2.0*sqrt(nfloat))
208:       if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
209:       call VecNorm(z(3),NORM_2,norm,ierr)
210:       v2 = abs(norm-3.0*sqrt(nfloat))
211:       if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
212:       if (rank .eq. 0) write(6,220) v,v1,v2
213:  220  format ('VecMAXPY ',3(1pe8.2))


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

219:       call VecDestroy(x,ierr)
220:       call VecDestroy(y,ierr)
221:       call VecDestroy(w,ierr)
222:       call VecDestroyVecsF90(ithree,z,ierr)
223:       call PetscFinalize(ierr)

225:       end