Inv

Returns inverse of matrix.

Calling example:

CALL Inv(A(:,:), InvA(:,:))
CALL Inv(A(:,:,:), InvA(:,:,:))

note

InvA should be allocated.

caution

Currently, Inv can compute inverse of matrix upto 4 by 4. To calculate inverse of big matrix use the following strategy:

First get LU decomposition:

CALL GetLU(A, LU, IPIV)

Then, calculate inverse by

CALL GetLU(A, invA, IPIV)

Interface 1

܀ Interface

INTERFACE
  MODULE PURE SUBROUTINE Inv(invA, A)
    REAL(DFP), INTENT(INOUT) :: invA(:, :)
    REAL(DFP), INTENT(IN) :: A(:, :)
  END SUBROUTINE Inv
END INTERFACE

️܀ See example

program main
use easifemBase
implicit none

real(dfp) :: amat(3,3), ainv(3,3)

call random_number(amat)
call display(Mdencode(amat), "amat: " // char_lf // char_lf)
call inv(invA=ainv, a=amat)
call display(Mdencode(ainv), "ainv: " // char_lf // char_lf)
end program main

See results

amat:

0.88179	0.51365	0.53015
0.24482	9.60291E-02	0.79165
0.25111	0.42564	9.45404E-04

ainv:

2.2076	-1.4756	-2.3312
-1.3012	0.86698	3.7241
-0.52488	1.6144	0.26919

↢

Interface 2

INTERFACE
  MODULE PURE SUBROUTINE Inv(invA, A)
    REAL(DFP), INTENT(INOUT) :: invA(:, :, :)
    REAL(DFP), INTENT(IN) :: A(:, :, :)
  END SUBROUTINE Inv
END INTERFACE