Actual source code: ex20f90.F90

petsc-master 2017-11-20
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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:  #include <petsc/finclude/petscvec.h>
 21:       use petscvec
 22:       implicit none

 24: !
 25: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 26: !                   Variable declarations
 27: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 28: !
 29: !  Variables:
 30: !     x, y, w - vectors
 31: !     z       - array of vectors
 32: !
 33:       type(tVec)       x,y,w
 34:       type(tVec), pointer :: z(:)

 36:       PetscReal norm,v,v1,v2,tol
 37:       PetscInt  n,ithree
 38:       PetscErrorCode ierr
 39:       PetscMPIInt  rank
 40:       PetscBool       flg
 41:       PetscScalar      one,two,three
 42:       PetscScalar      dots(3),dot
 43:       PetscReal        nfloat

 45: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 46: !                 Beginning of program
 47: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 49:       call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
 50:       if (ierr .ne. 0) then
 51:          print*,'Unable to initialize PETSc'
 52:          stop
 53:       endif

 55:       tol   = 1.e-10_PETSC_REAL_KIND
 56:       one   = 1.0
 57:       two   = 2.0
 58:       three = 3.0
 59:       n     = 20
 60:       ithree = 3

 62:       call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)
 63:       nfloat = n
 64:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(ierr)

 66: !  Create a vector, specifying only its global dimension.
 67: !  When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 68: !  the vector format (currently parallel
 69: !  or sequential) is determined at runtime.  Also, the parallel
 70: !  partitioning of the vector is determined by PETSc at runtime.
 71: !
 72: !  Routines for creating particular vector types directly are:
 73: !     VecCreateSeq() - uniprocessor vector
 74: !     VecCreateMPI() - distributed vector, where the user can
 75: !                      determine the parallel partitioning

 77:       call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr)
 78:       call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
 79:       call VecSetFromOptions(x,ierr);CHKERRA(ierr)

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

 84:       call VecDuplicate(x,y,ierr);CHKERRA(ierr)
 85:       call VecDuplicate(x,w,ierr);CHKERRA(ierr)

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

 92:       call VecDuplicateVecsF90(x,ithree,z,ierr);CHKERRA(ierr)

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

 96:       call VecSet(x,one,ierr);CHKERRA(ierr)
 97:       call VecSet(y,two,ierr);CHKERRA(ierr)
 98:       call VecSet(z(1),one,ierr);CHKERRA(ierr)
 99:       call VecSet(z(2),two,ierr);CHKERRA(ierr)
100:       call VecSet(z(3),three,ierr);CHKERRA(ierr)

102: !  Demonstrate various basic vector routines.

104:       call VecDot(x,x,dot,ierr);CHKERRA(ierr)
105:       call VecMDot(x,ithree,z,dots,ierr);CHKERRA(ierr)

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

111:       if (rank .eq. 0) then
112: #if defined(PETSC_USE_COMPLEX)
113:          write(6,100) int(PetscRealPart(dot))
114:          write(6,110) int(PetscRealPart(dots(1))),int(PetscRealPart(dots(2))),int(PetscRealPart(dots(3)))
115: #else
116:          write(6,100) int(dot)
117:          write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
118: #endif
119:          write(6,120)
120:       endif
121:  100  format ('Vector length ',i6)
122:  110  format ('Vector length ',3(i6))
123:  120  format ('All other values should be near zero')

125:       call VecScale(x,two,ierr);CHKERRA(ierr)
126:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
127:       v = abs(norm-2.0*sqrt(nfloat))
128:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
129:       if (rank .eq. 0) write(6,130) v
130:  130  format ('VecScale ',1pe8.2)

132:       call VecCopy(x,w,ierr);CHKERRA(ierr)
133:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
134:       v = abs(norm-2.0*sqrt(nfloat))
135:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
136:       if (rank .eq. 0) write(6,140) v
137:  140  format ('VecCopy ',1pe8.2)

139:       call VecAXPY(y,three,x,ierr);CHKERRA(ierr)
140:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
141:       v = abs(norm-8.0*sqrt(nfloat))
142:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
143:       if (rank .eq. 0) write(6,150) v
144:  150  format ('VecAXPY ',1pe8.2)

146:       call VecAYPX(y,two,x,ierr);CHKERRA(ierr)
147:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
148:       v = abs(norm-18.0*sqrt(nfloat))
149:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
150:       if (rank .eq. 0) write(6,160) v
151:  160  format ('VecAYXP ',1pe8.2)

153:       call VecSwap(x,y,ierr);CHKERRA(ierr)
154:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
155:       v = abs(norm-2.0*sqrt(nfloat))
156:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
157:       if (rank .eq. 0) write(6,170) v
158:  170  format ('VecSwap ',1pe8.2)

160:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
161:       v = abs(norm-18.0*sqrt(nfloat))
162:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
163:       if (rank .eq. 0) write(6,180) v
164:  180  format ('VecSwap ',1pe8.2)

166:       call VecWAXPY(w,two,x,y,ierr);CHKERRA(ierr)
167:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
168:       v = abs(norm-38.0*sqrt(nfloat))
169:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
170:       if (rank .eq. 0) write(6,190) v
171:  190  format ('VecWAXPY ',1pe8.2)

173:       call VecPointwiseMult(w,y,x,ierr);CHKERRA(ierr)
174:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
175:       v = abs(norm-36.0*sqrt(nfloat))
176:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
177:       if (rank .eq. 0) write(6,200) v
178:  200  format ('VecPointwiseMult ',1pe8.2)

180:       call VecPointwiseDivide(w,x,y,ierr);CHKERRA(ierr)
181:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
182:       v = abs(norm-9.0*sqrt(nfloat))
183:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
184:       if (rank .eq. 0) write(6,210) v
185:  210  format ('VecPointwiseDivide ',1pe8.2)


188:       dots(1) = one
189:       dots(2) = three
190:       dots(3) = two
191:       call VecSet(x,one,ierr);CHKERRA(ierr)
192:       call VecMAXPY(x,ithree,dots,z,ierr);CHKERRA(ierr)
193:       call VecNorm(z(1),NORM_2,norm,ierr);CHKERRA(ierr)
194:       v = abs(norm-sqrt(nfloat))
195:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
196:       call VecNorm(z(2),NORM_2,norm,ierr);CHKERRA(ierr)
197:       v1 = abs(norm-2.0*sqrt(nfloat))
198:       if (v1 .gt. -tol .and. v1 .lt. tol) v1 = 0.0
199:       call VecNorm(z(3),NORM_2,norm,ierr);CHKERRA(ierr)
200:       v2 = abs(norm-3.0*sqrt(nfloat))
201:       if (v2 .gt. -tol .and. v2 .lt. tol) v2 = 0.0
202:       if (rank .eq. 0) write(6,220) v,v1,v2
203:  220  format ('VecMAXPY ',3(1pe8.2))


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

209:       call VecDestroy(x,ierr);CHKERRA(ierr)
210:       call VecDestroy(y,ierr);CHKERRA(ierr)
211:       call VecDestroy(w,ierr);CHKERRA(ierr)
212:       call VecDestroyVecsF90(ithree,z,ierr);CHKERRA(ierr)
213:       call PetscFinalize(ierr)

215:       end