Date: 2022-03-31T04:46:30+00:00

Actual source code: ex20f90.F90

      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: !
     19: #include <petsc/finclude/petscvec.h>
     20:       use petscvec
     21:       implicit none

     23: !
     24: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     25: !                   Variable declarations
     26: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     27: !
     28: !  Variables:
     29: !     x, y, w - vectors
     30: !     z       - array of vectors
     31: !
     32:       type(tVec)       x,y,w
     33:       type(tVec), pointer :: z(:)

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

     44: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     45: !                 Beginning of program
     46: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

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

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

     61:       call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)
     62:       nfloat = n
     63:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(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);CHKERRA(ierr)
     77:       call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
     78:       call VecSetFromOptions(x,ierr);CHKERRA(ierr)

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

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

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

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

    101: !  Demonstrate various basic vector routines.

    103:       call VecDot(x,x,dot,ierr);CHKERRA(ierr)
    104:       call VecMDot(x,ithree,z,dots,ierr);CHKERRA(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))),int(PetscRealPart(dots(2))),int(PetscRealPart(dots(3)))
    114: #else
    115:          write(6,100) int(dot)
    116:          write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
    117: #endif
    118:          write(6,120)
    119:       endif
    120:  100  format ('Vector length ',i6)
    121:  110  format ('Vector length ',3(i6))
    122:  120  format ('All other values should be near zero')

    124:       call VecScale(x,two,ierr);CHKERRA(ierr)
    125:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
    126:       v = abs(norm-2.0*sqrt(nfloat))
    127:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    128:       if (rank .eq. 0) write(6,130) v
    129:  130  format ('VecScale ',1pe9.2)

    131:       call VecCopy(x,w,ierr);CHKERRA(ierr)
    132:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    133:       v = abs(norm-2.0*sqrt(nfloat))
    134:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    135:       if (rank .eq. 0) write(6,140) v
    136:  140  format ('VecCopy ',1pe9.2)

    138:       call VecAXPY(y,three,x,ierr);CHKERRA(ierr)
    139:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    140:       v = abs(norm-8.0*sqrt(nfloat))
    141:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    142:       if (rank .eq. 0) write(6,150) v
    143:  150  format ('VecAXPY ',1pe9.2)

    145:       call VecAYPX(y,two,x,ierr);CHKERRA(ierr)
    146:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    147:       v = abs(norm-18.0*sqrt(nfloat))
    148:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    149:       if (rank .eq. 0) write(6,160) v
    150:  160  format ('VecAYXP ',1pe9.2)

    152:       call VecSwap(x,y,ierr);CHKERRA(ierr)
    153:       call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
    154:       v = abs(norm-2.0*sqrt(nfloat))
    155:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    156:       if (rank .eq. 0) write(6,170) v
    157:  170  format ('VecSwap ',1pe9.2)

    159:       call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
    160:       v = abs(norm-18.0*sqrt(nfloat))
    161:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    162:       if (rank .eq. 0) write(6,180) v
    163:  180  format ('VecSwap ',1pe9.2)

    165:       call VecWAXPY(w,two,x,y,ierr);CHKERRA(ierr)
    166:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    167:       v = abs(norm-38.0*sqrt(nfloat))
    168:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    169:       if (rank .eq. 0) write(6,190) v
    170:  190  format ('VecWAXPY ',1pe9.2)

    172:       call VecPointwiseMult(w,y,x,ierr);CHKERRA(ierr)
    173:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    174:       v = abs(norm-36.0*sqrt(nfloat))
    175:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    176:       if (rank .eq. 0) write(6,200) v
    177:  200  format ('VecPointwiseMult ',1pe9.2)

    179:       call VecPointwiseDivide(w,x,y,ierr);CHKERRA(ierr)
    180:       call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
    181:       v = abs(norm-9.0*sqrt(nfloat))
    182:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    183:       if (rank .eq. 0) write(6,210) v
    184:  210  format ('VecPointwiseDivide ',1pe9.2)

    186:       dots(1) = one
    187:       dots(2) = three
    188:       dots(3) = two
    189:       call VecSet(x,one,ierr);CHKERRA(ierr)
    190:       call VecMAXPY(x,ithree,dots,z,ierr);CHKERRA(ierr)
    191:       call VecNorm(z(1),NORM_2,norm,ierr);CHKERRA(ierr)
    192:       v = abs(norm-sqrt(nfloat))
    193:       if (v .gt. -tol .and. v .lt. tol) v = 0.0
    194:       call VecNorm(z(2),NORM_2,norm,ierr);CHKERRA(ierr)
    195:       v1 = abs(norm-2.0*sqrt(nfloat))
    196:       if (v1 .gt. -tol .and. v1 .lt. tol) v1 = 0.0
    197:       call VecNorm(z(3),NORM_2,norm,ierr);CHKERRA(ierr)
    198:       v2 = abs(norm-3.0*sqrt(nfloat))
    199:       if (v2 .gt. -tol .and. v2 .lt. tol) v2 = 0.0
    200:       if (rank .eq. 0) write(6,220) v,v1,v2
    201:  220  format ('VecMAXPY ',3(1pe9.2))

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

    206:       call VecDestroy(x,ierr);CHKERRA(ierr)
    207:       call VecDestroy(y,ierr);CHKERRA(ierr)
    208:       call VecDestroy(w,ierr);CHKERRA(ierr)
    209:       call VecDestroyVecsF90(ithree,z,ierr);CHKERRA(ierr)
    210:       call PetscFinalize(ierr)

    212:       end

    214: !/*TEST
    215: !
    216: !     test:
    217: !
    218: !TEST*/