Date: 2015-09-03T15:05:48+00:00

Actual source code: ex16f90.F90
slepc-3.6.1 2015-09-03
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      1: !  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      2: !  SLEPc - Scalable Library for Eigenvalue Problem Computations
      3: !  Copyright (c) 2002-2015, Universitat Politecnica de Valencia, Spain
      4: !
      5: !  This file is part of SLEPc.
      6: !
      7: !  SLEPc is free software: you can redistribute it and/or modify it under  the
      8: !  terms of version 3 of the GNU Lesser General Public License as published by
      9: !  the Free Software Foundation.
     10: !
     11: !  SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
     12: !  WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
     13: !  FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
     14: !  more details.
     15: !
     16: !  You  should have received a copy of the GNU Lesser General  Public  License
     17: !  along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     18: !  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     19: !
     20: !  Program usage: mpirun -np n ex16f90 [-help] [-n <n>] [-m <m>] [SLEPc opts]
     21: !
     22: !  Description: Simple example that solves a quadratic eigensystem with the
     23: !  PEP object. This is the Fortran90 equivalent to ex16.c
     24: !
     25: !  The command line options are:
     26: !    -n <n>, where <n> = number of grid subdivisions in x dimension
     27: !    -m <m>, where <m> = number of grid subdivisions in y dimension
     28: !
     29: ! ----------------------------------------------------------------------
     30: !
     31:       program main

     33: #include <slepc/finclude/slepcpepdef.h>
     34:       use slepcpep

     36:       implicit none

     38: ! For usage without modules, uncomment the following lines and remove
     39: ! the previous lines between 'program main' and 'implicit none'
     40: !
     41: !#include <petsc/finclude/petsc.h>
     42: !#include <slepc/finclude/slepc.h>

     44: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     45: !     Declarations
     46: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     47: !
     48: !  Variables:
     49: !     M,C,K  problem matrices
     50: !     pep    polynomial eigenproblem solver context

     52: #if defined(PETSC_USE_FORTRAN_DATATYPES)
     53:       type(Mat)      M, C, K, A(3)
     54:       type(PEP)      pep
     55: #else
     56:       Mat            M, C, K, A(3)
     57:       PEP            pep
     58: #endif
     59:       PEPType        tname
     60:       PetscInt       N, nx, ny, i, j, Istart, Iend, II
     61:       PetscInt       nev, ithree
     62:       PetscMPIInt    rank
     63:       PetscErrorCode ierr
     64:       PetscBool      flg, terse
     65:       PetscScalar    one, mone, four

     67: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     68: !     Beginning of program
     69: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     71:       call SlepcInitialize(PETSC_NULL_CHARACTER,ierr)
     72:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
     73:       nx = 10
     74:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',nx,flg,ierr)
     75:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-m',ny,flg,ierr)
     76:       if (.not. flg) then
     77:         ny = nx
     78:       endif
     79:       N = nx*ny
     80:       if (rank .eq. 0) then
     81:         write(*,100) N, nx, ny
     82:       endif
     83:  100  format (/'Quadratic Eigenproblem, N=',I6,' (',I4,'x',I4,' grid)')

     85: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     86: !     Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     87: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     89: !     ** K is the 2-D Laplacian
     90:       call MatCreate(PETSC_COMM_WORLD,K,ierr)
     91:       call MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr)
     92:       call MatSetFromOptions(K,ierr)
     93:       call MatSetUp(K,ierr)
     94:       call MatGetOwnershipRange(K,Istart,Iend,ierr)
     95:       mone = -1.0
     96:       four = 4.0
     97:       do II=Istart,Iend-1
     98:         i = II/nx
     99:         j = II-i*nx
    100:         if (i .gt. 0) then
    101:           call MatSetValue(K,II,II-nx,mone,INSERT_VALUES,ierr)
    102:         endif
    103:         if (i .lt. ny-1) then
    104:           call MatSetValue(K,II,II+nx,mone,INSERT_VALUES,ierr)
    105:         endif
    106:         if (j .gt. 0) then
    107:           call MatSetValue(K,II,II-1,mone,INSERT_VALUES,ierr)
    108:         endif
    109:         if (j .lt. nx-1) then
    110:           call MatSetValue(K,II,II+1,mone,INSERT_VALUES,ierr)
    111:         endif
    112:         call MatSetValue(K,II,II,four,INSERT_VALUES,ierr)
    113:       end do
    114:       call MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY,ierr)
    115:       call MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY,ierr)

    117: !     ** C is the zero matrix
    118:       call MatCreate(PETSC_COMM_WORLD,C,ierr)
    119:       call MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr)
    120:       call MatSetFromOptions(C,ierr)
    121:       call MatSetUp(C,ierr)
    122:       call MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY,ierr)
    123:       call MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY,ierr)

    125: !     ** M is the identity matrix
    126:       call MatCreate(PETSC_COMM_WORLD,M,ierr)
    127:       call MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr)
    128:       call MatSetFromOptions(M,ierr)
    129:       call MatSetUp(M,ierr)
    130:       call MatGetOwnershipRange(M,Istart,Iend,ierr)
    131:       one = 1.0
    132:       do II=Istart,Iend-1
    133:         call MatSetValue(M,II,II,one,INSERT_VALUES,ierr)
    134:       end do
    135:       call MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY,ierr)
    136:       call MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY,ierr)

    138: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    139: !     Create the eigensolver and set various options
    140: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    142: !     ** Create eigensolver context
    143:       call PEPCreate(PETSC_COMM_WORLD,pep,ierr)

    145: !     ** Set matrices and problem type
    146:       A(1) = K
    147:       A(2) = C
    148:       A(3) = M
    149:       ithree = 3
    150:       call PEPSetOperators(pep,ithree,A,ierr)
    151:       call PEPSetProblemType(pep,PEP_GENERAL,ierr)

    153: !     ** Set solver parameters at runtime
    154:       call PEPSetFromOptions(pep,ierr)

    156: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    157: !     Solve the eigensystem
    158: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    160:       call PEPSolve(pep,ierr)

    162: !     ** Optional: Get some information from the solver and display it
    163:       call PEPGetType(pep,tname,ierr)
    164:       if (rank .eq. 0) then
    165:         write(*,120) tname
    166:       endif
    167:  120  format (' Solution method: ',A)
    168:       call PEPGetDimensions(pep,nev,PETSC_NULL_INTEGER,                 &
    169:      &                      PETSC_NULL_INTEGER,ierr)
    170:       if (rank .eq. 0) then
    171:         write(*,130) nev
    172:       endif
    173:  130  format (' Number of requested eigenvalues:',I4)

    175: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    176: !     Display solution and clean up
    177: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    179: !     ** show detailed info unless -terse option is given by user
    180:       call PetscOptionsHasName(PETSC_NULL_CHARACTER,'-terse',terse,ierr)
    181:       if (terse) then
    182:         call PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_NULL_OBJECT,ierr)
    183:       else
    184:         call PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,           &
    185:      &                   PETSC_VIEWER_ASCII_INFO_DETAIL,ierr)
    186:         call PEPReasonView(pep,PETSC_VIEWER_STDOUT_WORLD,ierr)
    187:         call PEPErrorView(pep,PEP_ERROR_BACKWARD,                       &
    188:      &                   PETSC_VIEWER_STDOUT_WORLD,ierr)
    189:         call PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD,ierr)
    190:       endif
    191:       call PEPDestroy(pep,ierr)
    192:       call MatDestroy(K,ierr)
    193:       call MatDestroy(C,ierr)
    194:       call MatDestroy(M,ierr)
    195:       call SlepcFinalize(ierr)
    196:       end