Date: 2013-07-02T14:40:20+00:00

Actual source code: ex1f90.F
petsc-3.4.2 2013-07-02

      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
     12:       implicit none

     14: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     15: !                    Include files
     16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     17: !
     18: !  The following include statements are required for Fortran programs
     19: !  that use PETSc vectors:
     20: !     petscsys.h       - base PETSc routines
     21: !     petscvec.h    - vectors
     22: !     petscvec.h90  - to allow access to Fortran90 features of vectors
     23: !
     24: !  Additional include statements may be needed if using additional
     25: !  PETSc routines in a Fortran program, e.g.,
     26: !     petscviewer.h - viewers
     27: !     petscis.h     - index sets
     28: !
     29: #include <finclude/petscsys.h>
     30: #include <finclude/petscvec.h>
     31: #include <finclude/petscvec.h90>
     32: !
     33: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     34: !                   Variable declarations
     35: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     36: !
     37: !  Variables:
     38: !     x, y, w - vectors
     39: !     z       - array of vectors
     40: !
     41:       Vec              x,y,w
     42:       Vec, pointer :: z(:)
     43:       double precision norm,v,v1,v2
     44:       PetscInt         n,ithree
     45:       PetscErrorCode   ierr
     46:       PetscMPIInt      rank
     47:       PetscBool        flg
     48:       PetscScalar      one,two,three
     49:       PetscScalar      dots(3),dot

     51: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     52: !                 Beginning of program
     53: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     55:       call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
     56:       one   = 1.0
     57:       two   = 2.0
     58:       three = 3.0
     59:       n     = 20
     60:       ithree = 3

     62:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
     63:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)

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

     76:       call VecCreate(PETSC_COMM_WORLD,x,ierr)
     77:       call VecSetSizes(x,PETSC_DECIDE,n,ierr)
     78:       call VecSetFromOptions(x,ierr)

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

     83:       call VecDuplicate(x,y,ierr)
     84:       call VecDuplicate(x,w,ierr)

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

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

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

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

    101: !  Demonstrate various basic vector routines.

    103:       call VecDot(x,x,dot,ierr)
    104:       call VecMDot(x,ithree,z,dots,ierr)

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

    110:       if (rank .eq. 0) then
    111: #if defined(PETSC_USE_COMPLEX)
    112:          write(6,100) int(PetscRealPart(dot))
    113:          write(6,110) int(PetscRealPart(dots(1))),                               &
    114:      &                int(PetscRealPart(dots(2))),                               &
    115:      &                int(PetscRealPart(dots(3)))
    116: #else
    117:          write(6,100) int(dot)
    118:          write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
    119: #endif
    120:          write(6,120)
    121:       endif
    122:  100  format ("Vector length ",i6)
    123:  110  format ("Vector length ",3(i6))
    124:  120  format ("All other values should be near zero")

    126:       call VecScale(x,two,ierr)
    127:       call VecNorm(x,NORM_2,norm,ierr)
    128:       v = norm-2.0*sqrt(dble(n))
    129:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    130:       if (rank .eq. 0) write(6,130) v
    131:  130  format ("VecScale ",1pe8.2)

    133:       call VecCopy(x,w,ierr)
    134:       call VecNorm(w,NORM_2,norm,ierr)
    135:       v = norm-2.0*sqrt(dble(n))
    136:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    137:       if (rank .eq. 0) write(6,140) v
    138:  140  format ("VecCopy ",1pe8.2)

    140:       call VecAXPY(y,three,x,ierr)
    141:       call VecNorm(y,NORM_2,norm,ierr)
    142:       v = norm-8.0*sqrt(dble(n))
    143:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    144:       if (rank .eq. 0) write(6,150) v
    145:  150  format ("VecAXPY ",1pe8.2)

    147:       call VecAYPX(y,two,x,ierr)
    148:       call VecNorm(y,NORM_2,norm,ierr)
    149:       v = norm-18.0*sqrt(dble(n))
    150:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    151:       if (rank .eq. 0) write(6,160) v
    152:  160  format ("VecAYXP ",1pe8.2)

    154:       call VecSwap(x,y,ierr)
    155:       call VecNorm(y,NORM_2,norm,ierr)
    156:       v = norm-2.0*sqrt(dble(n))
    157:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    158:       if (rank .eq. 0) write(6,170) v
    159:  170  format ("VecSwap ",1pe8.2)

    161:       call VecNorm(x,NORM_2,norm,ierr)
    162:       v = norm-18.0*sqrt(dble(n))
    163:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    164:       if (rank .eq. 0) write(6,180) v
    165:  180  format ("VecSwap ",1pe8.2)

    167:       call VecWAXPY(w,two,x,y,ierr)
    168:       call VecNorm(w,NORM_2,norm,ierr)
    169:       v = norm-38.0*sqrt(dble(n))
    170:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    171:       if (rank .eq. 0) write(6,190) v
    172:  190  format ("VecWAXPY ",1pe8.2)

    174:       call VecPointwiseMult(w,y,x,ierr)
    175:       call VecNorm(w,NORM_2,norm,ierr)
    176:       v = norm-36.0*sqrt(dble(n))
    177:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    178:       if (rank .eq. 0) write(6,200) v
    179:  200  format ("VecPointwiseMult ",1pe8.2)

    181:       call VecPointwiseDivide(w,x,y,ierr)
    182:       call VecNorm(w,NORM_2,norm,ierr)
    183:       v = norm-9.0*sqrt(dble(n))
    184:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    185:       if (rank .eq. 0) write(6,210) v
    186:  210  format ("VecPointwiseDivide ",1pe8.2)

    189:       dots(1) = one
    190:       dots(2) = three
    191:       dots(3) = two
    192:       call VecSet(x,one,ierr)
    193:       call VecMAXPY(x,ithree,dots,z,ierr)
    194:       call VecNorm(z(1),NORM_2,norm,ierr)
    195:       v = norm-sqrt(dble(n))
    196:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    197:       call VecNorm(z(2),NORM_2,norm,ierr)
    198:       v1 = norm-2.0*sqrt(dble(n))
    199:       if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
    200:       call VecNorm(z(3),NORM_2,norm,ierr)
    201:       v2 = norm-3.0*sqrt(dble(n))
    202:       if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
    203:       if (rank .eq. 0) write(6,220) v,v1,v2
    204:  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)
    210:       call VecDestroy(y,ierr)
    211:       call VecDestroy(w,ierr)
    212:       call VecDestroyVecsF90(ithree,z,ierr)
    213:       call PetscFinalize(ierr)

    215:       end