Actual source code: ex16f.F90

      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> ./ex16f [-help] [-n <n>] [-m <m>] [SLEPc opts]
     11: !
     12: !  Description: Simple example that solves a quadratic eigensystem with PEP.
     13: !  This is the Fortran90 equivalent to ex16.c
     14: !
     15: !  The command line options are:
     16: !    -n <n>, where <n> = number of grid subdivisions in x dimension
     17: !    -m <m>, where <m> = number of grid subdivisions in y dimension
     18: !
     19: ! ----------------------------------------------------------------------
     20: !
     21:       program main
     22: #include <slepc/finclude/slepcpep.h>
     23:       use slepcpep
     24:       implicit none

     26: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     27: !     Declarations
     28: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     29: !
     30: !  Variables:
     31: !     M,C,K  problem matrices
     32: !     pep    polynomial eigenproblem solver context

     34:       Mat            M, C, K, A(3)
     35:       PEP            pep
     36:       PEPType        tname
     37:       PetscInt       N, nx, ny, i, j, Istart, Iend, II
     38:       PetscInt       nev, ithree
     39:       PetscMPIInt    rank
     40:       PetscErrorCode ierr
     41:       PetscBool      flg, terse
     42:       PetscScalar    mone, two, four, val

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

     48:       PetscCallA(SlepcInitialize(PETSC_NULL_CHARACTER,ierr))
     49:       PetscCallMPIA(MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr))
     50:       nx = 10
     51:       PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',nx,flg,ierr))
     52:       PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-m',ny,flg,ierr))
     53:       if (.not. flg) then
     54:         ny = nx
     55:       endif
     56:       N = nx*ny
     57:       if (rank .eq. 0) then
     58:         write(*,100) N, nx, ny
     59:       endif
     60:  100  format (/'Quadratic Eigenproblem, N=',I6,' (',I4,'x',I4,' grid)')

     62: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     63: !     Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     64: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     66: !     ** K is the 2-D Laplacian
     67:       PetscCallA(MatCreate(PETSC_COMM_WORLD,K,ierr))
     68:       PetscCallA(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr))
     69:       PetscCallA(MatSetFromOptions(K,ierr))
     70:       PetscCallA(MatGetOwnershipRange(K,Istart,Iend,ierr))
     71:       mone = -1.0
     72:       four = 4.0
     73:       do II=Istart,Iend-1
     74:         i = II/nx
     75:         j = II-i*nx
     76:         if (i .gt. 0) then
     77:           PetscCallA(MatSetValue(K,II,II-nx,mone,INSERT_VALUES,ierr))
     78:         endif
     79:         if (i .lt. ny-1) then
     80:           PetscCallA(MatSetValue(K,II,II+nx,mone,INSERT_VALUES,ierr))
     81:         endif
     82:         if (j .gt. 0) then
     83:           PetscCallA(MatSetValue(K,II,II-1,mone,INSERT_VALUES,ierr))
     84:         endif
     85:         if (j .lt. nx-1) then
     86:           PetscCallA(MatSetValue(K,II,II+1,mone,INSERT_VALUES,ierr))
     87:         endif
     88:         PetscCallA(MatSetValue(K,II,II,four,INSERT_VALUES,ierr))
     89:       end do
     90:       PetscCallA(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY,ierr))
     91:       PetscCallA(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY,ierr))

     93: !     ** C is the 1-D Laplacian on horizontal lines
     94:       PetscCallA(MatCreate(PETSC_COMM_WORLD,C,ierr))
     95:       PetscCallA(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr))
     96:       PetscCallA(MatSetFromOptions(C,ierr))
     97:       PetscCallA(MatGetOwnershipRange(C,Istart,Iend,ierr))
     98:       two = 2.0
     99:       do II=Istart,Iend-1
    100:         i = II/nx
    101:         j = II-i*nx
    102:         if (j .gt. 0) then
    103:           PetscCallA(MatSetValue(C,II,II-1,mone,INSERT_VALUES,ierr))
    104:         endif
    105:         if (j .lt. nx-1) then
    106:           PetscCallA(MatSetValue(C,II,II+1,mone,INSERT_VALUES,ierr))
    107:         endif
    108:         PetscCallA(MatSetValue(C,II,II,two,INSERT_VALUES,ierr))
    109:       end do
    110:       PetscCallA(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY,ierr))
    111:       PetscCallA(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY,ierr))

    113: !     ** M is a diagonal matrix
    114:       PetscCallA(MatCreate(PETSC_COMM_WORLD,M,ierr))
    115:       PetscCallA(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr))
    116:       PetscCallA(MatSetFromOptions(M,ierr))
    117:       PetscCallA(MatGetOwnershipRange(M,Istart,Iend,ierr))
    118:       do II=Istart,Iend-1
    119:         val = II+1
    120:         PetscCallA(MatSetValue(M,II,II,val,INSERT_VALUES,ierr))
    121:       end do
    122:       PetscCallA(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY,ierr))
    123:       PetscCallA(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY,ierr))

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

    129: !     ** Create eigensolver context
    130:       PetscCallA(PEPCreate(PETSC_COMM_WORLD,pep,ierr))

    132: !     ** Set matrices and problem type
    133:       A(1) = K
    134:       A(2) = C
    135:       A(3) = M
    136:       ithree = 3
    137:       PetscCallA(PEPSetOperators(pep,ithree,A,ierr))
    138:       PetscCallA(PEPSetProblemType(pep,PEP_GENERAL,ierr))

    140: !     ** Set solver parameters at runtime
    141:       PetscCallA(PEPSetFromOptions(pep,ierr))

    143: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    144: !     Solve the eigensystem
    145: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    147:       PetscCallA(PEPSolve(pep,ierr))

    149: !     ** Optional: Get some information from the solver and display it
    150:       PetscCallA(PEPGetType(pep,tname,ierr))
    151:       if (rank .eq. 0) then
    152:         write(*,120) tname
    153:       endif
    154:  120  format (' Solution method: ',A)
    155:       PetscCallA(PEPGetDimensions(pep,nev,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,ierr))
    156:       if (rank .eq. 0) then
    157:         write(*,130) nev
    158:       endif
    159:  130  format (' Number of requested eigenvalues:',I4)

    161: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    162: !     Display solution and clean up
    163: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    165: !     ** show detailed info unless -terse option is given by user
    166:       PetscCallA(PetscOptionsHasName(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-terse',terse,ierr))
    167:       if (terse) then
    168:         PetscCallA(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_NULL_VIEWER,ierr))
    169:       else
    170:         PetscCallA(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL,ierr))
    171:         PetscCallA(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD,ierr))
    172:         PetscCallA(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD,ierr))
    173:         PetscCallA(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD,ierr))
    174:       endif
    175:       PetscCallA(PEPDestroy(pep,ierr))
    176:       PetscCallA(MatDestroy(K,ierr))
    177:       PetscCallA(MatDestroy(C,ierr))
    178:       PetscCallA(MatDestroy(M,ierr))
    179:       PetscCallA(SlepcFinalize(ierr))
    180:       end

    182: !/*TEST
    183: !
    184: !   test:
    185: !      suffix: 1
    186: !      args: -pep_nev 4 -pep_ncv 19 -terse
    187: !      requires: !complex
    188: !
    189: !TEST*/