Date: 2022-11-02T11:47:03+00:00

Actual source code: ex10f90.F90
slepc-3.18.1 2022-11-02
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      1: !
      2: !  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3: !  SLEPc - Scalable Library for Eigenvalue Problem Computations
      4: !  Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain
      5: !
      6: !  This file is part of SLEPc.
      7: !  SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8: !  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: !
     10: !  Program usage: mpiexec -n <np> ./ex10f [-help] [-n <n>] [all SLEPc options]
     11: !
     12: !  Description: Illustrates the use of shell spectral transformations.
     13: !  The problem to be solved is the same as ex1.c and corresponds to the
     14: !  Laplacian operator in 1 dimension
     15: !
     16: !  The command line options are:
     17: !    nm <n>, where <n> is the number of grid subdivisions = matrix dimension
     18: !
     19: !  Note: this example illustrates old error checking with CHKERRA instead
     20: !  of PetscCallA()
     21: ! ----------------------------------------------------------------------
     22: !
     23: !     Module contains data needed by shell ST
     24: !
     25:       module mymoduleex10f90
     26: #include <slepc/finclude/slepceps.h>
     27:       use slepceps
     28:       implicit none

     30:       KSP myksp
     31:       end module

     33: ! ----------------------------------------------------------------------

     35:       program main
     36: #include <slepc/finclude/slepceps.h>
     37:       use slepceps
     38:       use mymoduleex10f90
     39:       implicit none

     41: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     42: !     Declarations
     43: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     44: !
     45: !  Variables:
     46: !     A     operator matrix
     47: !     eps   eigenproblem solver context

     49:       Mat            A
     50:       EPS            eps
     51:       ST             st
     52:       EPSType        tname
     53:       PetscInt       n, i, Istart, Iend, one, two, three
     54:       PetscInt       nev, row(1), col(3)
     55:       PetscScalar    val(3)
     56:       PetscBool      flg, isShell, terse
     57:       PetscMPIInt    rank
     58:       PetscErrorCode ierr

     60: !     Note: Any user-defined Fortran routines MUST be declared as external.
     61:       external STApply_User, STApplyTranspose_User, STBackTransform_User

     63: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     64: !     Beginning of program
     65: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     67:       one = 1
     68:       two = 2
     69:       three = 3
     70:       call SlepcInitialize(PETSC_NULL_CHARACTER,ierr)
     71:       if (ierr .ne. 0) then
     72:         print*,'SlepcInitialize failed'
     73:         stop
     74:       endif
     75:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRMPIA(ierr)
     76:       n = 30
     77:       call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)

     79:       if (rank .eq. 0) then
     80:         write(*,'(/A,I6/)') '1-D Laplacian Eigenproblem (shell-enabled), n=',n
     81:       endif

     83: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     84: !     Compute the operator matrix that defines the eigensystem, Ax=kx
     85: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     87:       call MatCreate(PETSC_COMM_WORLD,A,ierr);CHKERRA(ierr)
     88:       call MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n,ierr);CHKERRA(ierr)
     89:       call MatSetFromOptions(A,ierr);CHKERRA(ierr)
     90:       call MatSetUp(A,ierr);CHKERRA(ierr)

     92:       call MatGetOwnershipRange(A,Istart,Iend,ierr);CHKERRA(ierr)
     93:       if (Istart .eq. 0) then
     94:         row(1) = 0
     95:         col(1) = 0
     96:         col(2) = 1
     97:         val(1) =  2.0
     98:         val(2) = -1.0
     99:         call MatSetValues(A,one,row,two,col,val,INSERT_VALUES,ierr);CHKERRA(ierr)
    100:         Istart = Istart+1
    101:       endif
    102:       if (Iend .eq. n) then
    103:         row(1) = n-1
    104:         col(1) = n-2
    105:         col(2) = n-1
    106:         val(1) = -1.0
    107:         val(2) =  2.0
    108:         call MatSetValues(A,one,row,two,col,val,INSERT_VALUES,ierr);CHKERRA(ierr)
    109:         Iend = Iend-1
    110:       endif
    111:       val(1) = -1.0
    112:       val(2) =  2.0
    113:       val(3) = -1.0
    114:       do i=Istart,Iend-1
    115:         row(1) = i
    116:         col(1) = i-1
    117:         col(2) = i
    118:         col(3) = i+1
    119:         call MatSetValues(A,one,row,three,col,val,INSERT_VALUES,ierr);CHKERRA(ierr)
    120:       enddo

    122:       call MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY,ierr);CHKERRA(ierr)
    123:       call MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY,ierr);CHKERRA(ierr)

    125: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    126: !     Create the eigensolver and set various options
    127: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    129: !     ** Create eigensolver context
    130:       call EPSCreate(PETSC_COMM_WORLD,eps,ierr);CHKERRA(ierr)

    132: !     ** Set operators. In this case, it is a standard eigenvalue problem
    133:       call EPSSetOperators(eps,A,PETSC_NULL_MAT,ierr);CHKERRA(ierr)
    134:       call EPSSetProblemType(eps,EPS_NHEP,ierr);CHKERRA(ierr)

    136: !     ** Set solver parameters at runtime
    137:       call EPSSetFromOptions(eps,ierr);CHKERRA(ierr)

    139: !     ** Initialize shell spectral transformation if selected by user
    140:       call EPSGetST(eps,st,ierr);CHKERRA(ierr)
    141:       call PetscObjectTypeCompare(st,STSHELL,isShell,ierr);CHKERRA(ierr)

    143:       if (isShell) then
    144: !       ** Change sorting criterion since this ST example computes values
    145: !       ** closest to 0
    146:         call EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL,ierr);CHKERRA(ierr)

    148: !       ** In Fortran, instead of a context for the user-defined spectral transform
    149: !       ** we use a module containing any application-specific data, initialized here
    150:         call KSPCreate(PETSC_COMM_WORLD,myksp,ierr);CHKERRA(ierr)
    151:         call KSPAppendOptionsPrefix(myksp,"st_",ierr);CHKERRA(ierr)

    153: !       ** (Required) Set the user-defined routine for applying the operator
    154:         call STShellSetApply(st,STApply_User,ierr);CHKERRA(ierr)

    156: !       ** (Optional) Set the user-defined routine for applying the transposed operator
    157:         call STShellSetApplyTranspose(st,STApplyTranspose_User,ierr);CHKERRA(ierr)

    159: !       ** (Optional) Set the user-defined routine for back-transformation
    160:         call STShellSetBackTransform(st,STBackTransform_User,ierr);CHKERRA(ierr)

    162: !       ** (Optional) Set a name for the transformation, used for STView()
    163:         call PetscObjectSetName(st,'MyTransformation',ierr);CHKERRA(ierr)

    165: !       ** (Optional) Do any setup required for the new transformation
    166:         call KSPSetOperators(myksp,A,A,ierr);CHKERRA(ierr)
    167:         call KSPSetFromOptions(myksp,ierr);CHKERRA(ierr)
    168:       endif

    170: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    171: !     Solve the eigensystem
    172: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    174:       call EPSSolve(eps,ierr);CHKERRA(ierr)

    176: !     ** Optional: Get some information from the solver and display it
    177:       call EPSGetType(eps,tname,ierr);CHKERRA(ierr)
    178:       if (rank .eq. 0) then
    179:         write(*,'(A,A,/)') ' Solution method: ', tname
    180:       endif
    181:       call EPSGetDimensions(eps,nev,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,ierr);CHKERRA(ierr)
    182:       if (rank .eq. 0) then
    183:         write(*,'(A,I2)') ' Number of requested eigenvalues:',nev
    184:       endif

    186: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    187: !     Display solution and clean up
    188: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    190: !     ** show detailed info unless -terse option is given by user
    191:       call PetscOptionsHasName(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-terse',terse,ierr);CHKERRA(ierr)
    192:       if (terse) then
    193:         call EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_NULL_VIEWER,ierr);CHKERRA(ierr)
    194:       else
    195:         call PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL,ierr);CHKERRA(ierr)
    196:         call EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD,ierr);CHKERRA(ierr)
    197:         call EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD,ierr);CHKERRA(ierr)
    198:         call PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD,ierr);CHKERRA(ierr)
    199:       endif
    200:       if (isShell) then
    201:         call KSPDestroy(myksp,ierr);CHKERRA(ierr)
    202:       endif
    203:       call EPSDestroy(eps,ierr);CHKERRA(ierr)
    204:       call MatDestroy(A,ierr);CHKERRA(ierr)
    205:       call SlepcFinalize(ierr)
    206:       end

    208: ! -------------------------------------------------------------------
    209: !
    210: !   STApply_User - This routine demonstrates the use of a user-provided spectral
    211: !   transformation. The transformation implemented in this code is just OP=A^-1.
    212: !
    213: !   Input Parameters:
    214: !   st - spectral transformation context
    215: !   x - input vector
    216: !
    217: !   Output Parameter:
    218: !   y - output vector
    219: !
    220:       subroutine STApply_User(st,x,y,ierr)
    221: #include <slepc/finclude/slepceps.h>
    222:       use slepceps
    223:       use mymoduleex10f90
    224:       implicit none

    226:       ST             st
    227:       Vec            x,y
    228:       PetscErrorCode ierr

    230:       call KSPSolve(myksp,x,y,ierr);CHKERRQ(ierr)

    232:       return
    233:       end

    235: ! -------------------------------------------------------------------
    236: !
    237: !   STApplyTranspose_User - This is not required unless using a two-sided eigensolver
    238: !
    239: !   Input Parameters:
    240: !   st - spectral transformation context
    241: !   x - input vector
    242: !
    243: !   Output Parameter:
    244: !   y - output vector
    245: !
    246:       subroutine STApplyTranspose_User(st,x,y,ierr)
    247: #include <slepc/finclude/slepceps.h>
    248:       use slepceps
    249:       use mymoduleex10f90
    250:       implicit none

    252:       ST             st
    253:       Vec            x,y
    254:       PetscErrorCode ierr

    256:       call KSPSolveTranspose(myksp,x,y,ierr);CHKERRQ(ierr)

    258:       return
    259:       end

    261: ! -------------------------------------------------------------------
    262: !
    263: !   STBackTransform_User - This routine demonstrates the use of a user-provided spectral
    264: !   transformation
    265: !
    266: !   Input Parameters:
    267: !   st - spectral transformation context
    268: !   n  - number of eigenvalues to transform
    269: !
    270: !   Output Parameters:
    271: !   eigr - real part of eigenvalues
    272: !   eigi - imaginary part of eigenvalues
    273: !
    274:       subroutine STBackTransform_User(st,n,eigr,eigi,ierr)
    275: #include <slepc/finclude/slepceps.h>
    276:       use slepceps
    277:       use mymoduleex10f90
    278:       implicit none

    280:       ST             st
    281:       PetscInt       n, j
    282:       PetscScalar    eigr(*), eigi(*)
    283:       PetscErrorCode ierr

    285:       do j=1,n
    286:         eigr(j) = 1.0 / eigr(j)
    287:       enddo
    288:       ierr = 0

    290:       return
    291:       end

    293: !/*TEST
    294: !
    295: !   testset:
    296: !      args: -eps_nev 5 -eps_non_hermitian -terse
    297: !      output_file: output/ex10_1.out
    298: !      test:
    299: !         suffix: 1_sinvert
    300: !         args: -st_type sinvert
    301: !      test:
    302: !         suffix: 1_shell
    303: !         args: -st_type shell
    304: !         requires: !single
    305: !
    306: !TEST*/