Date: 2013-09-02T10:07:38+00:00

Actual source code: ex16f90.F90

      1: !  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      2: !  SLEPc - Scalable Library for Eigenvalue Problem Computations
      3: !  Copyright (c) 2002-2013, 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: !  QEP 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 <finclude/slepcqepdef.h>
     34:       use slepcqep

     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 <finclude/petsc.h>
     42: !#include <finclude/slepc.h>

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

     52: #if defined(PETSC_USE_FORTRAN_DATATYPES)
     53:       type(Mat)      M, C, K
     54:       type(QEP)      solver
     55: #else
     56:       Mat            M, C, K
     57:       QEP            solver
     58: #endif
     59:       QEPType        tname
     60:       PetscReal      tol
     61:       PetscInt       N, nx, ny, i, j, Istart, Iend, II
     62:       PetscInt       nev, maxit
     63:       PetscMPIInt    rank
     64:       PetscErrorCode ierr
     65:       PetscBool      flg
     66:       PetscScalar    one, mone, four

     68: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     69: !     Beginning of program
     70: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

     72:       call SlepcInitialize(PETSC_NULL_CHARACTER,ierr)
     73:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
     74:       nx = 10
     75:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',nx,flg,ierr)
     76:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-m',ny,flg,ierr)
     77:       if (.not. flg) then
     78:         ny = nx
     79:       endif
     80:       N = nx*ny
     81:       if (rank .eq. 0) then
     82:         write(*,100) N, nx, ny
     83:       endif
     84:  100  format (/'Quadratic Eigenproblem, N=',I6,' (',I4,'x',I4,' grid)')

     86: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     87: !     Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     88: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

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

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

    126: !     ** M is the identity matrix
    127:       call MatCreate(PETSC_COMM_WORLD,M,ierr)
    128:       call MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N,ierr)
    129:       call MatSetFromOptions(M,ierr)
    130:       call MatSetUp(M,ierr)
    131:       call MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY,ierr)
    132:       call MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY,ierr)
    133:       one = 1.0
    134:       call MatShift(M,one,ierr)

    136: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    137: !     Create the eigensolver and set various options
    138: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    140: !     ** Create eigensolver context
    141:       call QEPCreate(PETSC_COMM_WORLD,solver,ierr)

    143: !     ** Set matrices and problem type
    144:       call QEPSetOperators(solver,M,C,K,ierr)
    145:       call QEPSetProblemType(solver,QEP_GENERAL,ierr)

    147: !     ** Set solver parameters at runtime
    148:       call QEPSetFromOptions(solver,ierr)

    150: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    151: !     Solve the eigensystem
    152: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    154:       call QEPSolve(solver,ierr)

    156: !     ** Optional: Get some information from the solver and display it
    157:       call QEPGetType(solver,tname,ierr)
    158:       if (rank .eq. 0) then
    159:         write(*,120) tname
    160:       endif
    161:  120  format (' Solution method: ',A)
    162:       call QEPGetDimensions(solver,nev,PETSC_NULL_INTEGER,              &
    163:      &                      PETSC_NULL_INTEGER,ierr)
    164:       if (rank .eq. 0) then
    165:         write(*,130) nev
    166:       endif
    167:  130  format (' Number of requested eigenvalues:',I4)
    168:       call QEPGetTolerances(solver,tol,maxit,ierr)
    169:       if (rank .eq. 0) then
    170:         write(*,140) tol, maxit
    171:       endif
    172:  140  format (' Stopping condition: tol=',1P,E10.4,', maxit=',I4)

    174: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    175: !     Display solution and clean up
    176: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    178:       call QEPPrintSolution(solver,PETSC_NULL_OBJECT,ierr)
    179:       call QEPDestroy(solver,ierr)
    180:       call MatDestroy(K,ierr)
    181:       call MatDestroy(C,ierr)
    182:       call MatDestroy(M,ierr)
    183:       call SlepcFinalize(ierr)
    184:       end