Fortran Wiki
Matrix inversion (Rev #1, changes)

Skip the Navigation Links | Home Page | All Pages | Recently Revised | Authors | Feeds | Export |

Showing changes from revision #0 to #1: (追記) Added (追記ここまで) | (削除) Removed (削除ここまで) | (削除) Chan (削除ここまで)(追記) ged (追記ここまで)

! Returns the inverse of a matrix calculated by finding the LU
! decomposition. Depends on LAPACK.
function inv(A) result(Ainv)
 real(dp), dimension(:,:), intent(in) :: A
 real(dp), dimension(size(A,1),size(A,2)) :: Ainv
 real(dp), dimension(size(A,1)) :: work ! work array for LAPACK
 integer, dimension(size(A,1)) :: ipiv ! pivot indices
 integer :: n, info
 ! External procedures defined in LAPACK
 external DGETRF
 external DGETRI
 ! Store A in Ainv to prevent it from being overwritten by LAPACK
 Ainv = A
 n = size(A,1)
 ! DGETRF computes an LU factorization of a general M-by-N matrix A
 ! using partial pivoting with row interchanges.
 call DGETRF(n, n, Ainv, n, ipiv, info)
 if (info /= 0) then
 stop 'Matrix is numerically singular!'
 end if
 ! DGETRI computes the inverse of a matrix using the LU factorization
 ! computed by DGETRF.
 call DGETRI(n, Ainv, n, ipiv, work, n, info)
 if (info /= 0) then
 stop 'Matrix inversion failed!'
 end if
end function inv

Revision from March 13, 2010 00:16:03 by Jason Blevins

Forward in time (to current) | See current | History | Rollback | View: Source