Actual source code: ex1f90.F90
petsc-3.12.4 2020-02-04
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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
     12:  #include <petsc/finclude/petscvec.h>
     13:       use petscvec
     14:       implicit none

     16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     17: !                   Variable declarations
     18: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     19: !
     20: !  Variables:
     21: !     x, y, w - vectors
     22: !     z       - array of vectors
     23: !
     24:       Vec              x,y,w
     25:       Vec, pointer :: z(:)
     26:       PetscReal norm,v,v1,v2
     27:       PetscInt         n,ithree
     28:       PetscErrorCode   ierr
     29:       PetscMPIInt      rank
     30:       PetscBool        flg
     31:       PetscScalar      one,two,three
     32:       PetscScalar      dots(3),dot
     33:       PetscReal        nfloat

     35: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     36: !                 Beginning of program
     37: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     39:       call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
     40:       if (ierr .ne. 0) then
     41:         print*,'Unable to initialize PETSc'
     42:         stop
     43:       endif
     44:       one   = 1.0
     45:       two   = 2.0
     46:       three = 3.0
     47:       n     = 20
     48:       ithree = 3

     50:       call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)
     51:       nfloat = n
     52:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(ierr)

     54: !  Create a vector, specifying only its global dimension.
     55: !  When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
     56: !  the vector format (currently parallel
     57: !  or sequential) is determined at runtime.  Also, the parallel
     58: !  partitioning of the vector is determined by PETSc at runtime.
     59: !
     60: !  Routines for creating particular vector types directly are:
     61: !     VecCreateSeq() - uniprocessor vector
     62: !     VecCreateMPI() - distributed vector, where the user can
     63: !                      determine the parallel partitioning

     65:       call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr)
     66:       call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
     67:       call VecSetFromOptions(x,ierr);CHKERRA(ierr)

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

     72:       call VecDuplicate(x,y,ierr);CHKERRA(ierr)
     73:       call VecDuplicate(x,w,ierr);CHKERRA(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:       call VecDuplicateVecsF90(x,ithree,z,ierr);CHKERRA(ierr)

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

     84:       call VecSet(x,one,ierr);CHKERRA(ierr)
     85:       call VecSet(y,two,ierr);CHKERRA(ierr)
     86:       call VecSet(z(1),one,ierr);CHKERRA(ierr)
     87:       call VecSet(z(2),two,ierr);CHKERRA(ierr)
     88:       call VecSet(z(3),three,ierr);CHKERRA(ierr)

     90: !  Demonstrate various basic vector routines.

     92:       call VecDot(x,x,dot,ierr);CHKERRA(ierr)
     93:       call VecMDot(x,ithree,z,dots,ierr);CHKERRA(ierr)

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

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

    113:       call VecScale(x,two,ierr);CHKERRA(ierr)
    114:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
    115:       v = abs(norm-2.0*sqrt(nfloat))
    116:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    117:       if (rank .eq. 0) write(6,130) v
    118:  130  format ('VecScale ',1pe9.2)

    120:       call VecCopy(x,w,ierr);CHKERRA(ierr)
    121:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    122:       v = abs(norm-2.0*sqrt(nfloat))
    123:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    124:       if (rank .eq. 0) write(6,140) v
    125:  140  format ('VecCopy ',1pe9.2)

    127:       call VecAXPY(y,three,x,ierr);CHKERRA(ierr)
    128:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    129:       v = abs(norm-8.0*sqrt(nfloat))
    130:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    131:       if (rank .eq. 0) write(6,150) v
    132:  150  format ('VecAXPY ',1pe9.2)

    134:       call VecAYPX(y,two,x,ierr);CHKERRA(ierr)
    135:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    136:       v = abs(norm-18.0*sqrt(nfloat))
    137:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    138:       if (rank .eq. 0) write(6,160) v
    139:  160  format ('VecAYXP ',1pe9.2)

    141:       call VecSwap(x,y,ierr);CHKERRA(ierr)
    142:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    143:       v = abs(norm-2.0*sqrt(nfloat))
    144:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    145:       if (rank .eq. 0) write(6,170) v
    146:  170  format ('VecSwap ',1pe9.2)

    148:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
    149:       v = abs(norm-18.0*sqrt(nfloat))
    150:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    151:       if (rank .eq. 0) write(6,180) v
    152:  180  format ('VecSwap ',1pe9.2)

    154:       call VecWAXPY(w,two,x,y,ierr);CHKERRA(ierr)
    155:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    156:       v = abs(norm-38.0*sqrt(nfloat))
    157:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    158:       if (rank .eq. 0) write(6,190) v
    159:  190  format ('VecWAXPY ',1pe9.2)

    161:       call VecPointwiseMult(w,y,x,ierr);CHKERRA(ierr)
    162:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    163:       v = abs(norm-36.0*sqrt(nfloat))
    164:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    165:       if (rank .eq. 0) write(6,200) v
    166:  200  format ('VecPointwiseMult ',1pe9.2)

    168:       call VecPointwiseDivide(w,x,y,ierr);CHKERRA(ierr)
    169:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    170:       v = abs(norm-9.0*sqrt(nfloat))
    171:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    172:       if (rank .eq. 0) write(6,210) v
    173:  210  format ('VecPointwiseDivide ',1pe9.2)

    176:       dots(1) = one
    177:       dots(2) = three
    178:       dots(3) = two
    179:       call VecSet(x,one,ierr);CHKERRA(ierr)
    180:       call VecMAXPY(x,ithree,dots,z,ierr);CHKERRA(ierr)
    181:       call VecNorm(z(1),NORM_2,norm,ierr);CHKERRA(ierr)
    182:       v = abs(norm-sqrt(nfloat))
    183:       if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
    184:       call VecNorm(z(2),NORM_2,norm,ierr);CHKERRA(ierr)
    185:       v1 = abs(norm-2.0*sqrt(nfloat))
    186:       if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
    187:       call VecNorm(z(3),NORM_2,norm,ierr);CHKERRA(ierr)
    188:       v2 = abs(norm-3.0*sqrt(nfloat))
    189:       if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
    190:       if (rank .eq. 0) write(6,220) v,v1,v2
    191:  220  format ('VecMAXPY ',3(1pe9.2))

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

    196:       call VecDestroy(x,ierr);CHKERRA(ierr)
    197:       call VecDestroy(y,ierr);CHKERRA(ierr)
    198:       call VecDestroy(w,ierr);CHKERRA(ierr)
    199:       call VecDestroyVecsF90(ithree,z,ierr);CHKERRA(ierr)
    200:       call PetscFinalize(ierr)

    202:       end

    204: !
    205: !/*TEST
    206: !
    207: !     test:
    208: !       nsize: 2
    209: !
    210: !TEST*/