INV33 Function

public pure function INV33(Mat, Det_in)

compute inverse of 3x3 matrix, needs sDet=1/det(Mat)

Arguments

Type IntentOptional Attributes Name
real(kind=wp), intent(in) :: Mat(3,3)

input matrix
real(kind=wp), intent(in), optional :: Det_in

determinant of input matrix (otherwise computed here)

Return Value real(kind=wp), (3,3)

inverse matrix


Calls

proc~~inv33~~CallsGraph proc~inv33 INV33 interface~det33 DET33 proc~inv33->interface~det33 interface~det33->interface~det33

Source Code

PURE FUNCTION INV33(Mat, Det_in)
! MODULES
IMPLICIT NONE
!-----------------------------------------------------------------------------------------------------------------------------------
! INPUT VARIABLES
REAL(wp),INTENT(IN)             :: Mat(3,3) !! input matrix
REAL(wp),INTENT(IN),OPTIONAL    ::  Det_in  !! determinant of input matrix (otherwise computed here)
!-----------------------------------------------------------------------------------------------------------------------------------
! OUTPUT VARIABLES
REAL(wp)             :: INV33(3,3) !! inverse matrix
!-----------------------------------------------------------------------------------------------------------------------------------
! LOCAL VARIABLES
REAL(wp)             :: sDet
!===================================================================================================================================
IF(PRESENT(Det_in))THEN
  sDet=1.0_wp/Det_in
ELSE
  sDet=1.0_wp/DET33(Mat)
END IF
INV33(1,1) = ( Mat(2,2) * Mat(3,3) - Mat(2,3) * Mat(3,2) ) * sDet
INV33(1,2) = ( Mat(1,3) * Mat(3,2) - Mat(1,2) * Mat(3,3) ) * sDet
INV33(1,3) = ( Mat(1,2) * Mat(2,3) - Mat(1,3) * Mat(2,2) ) * sDet
INV33(2,1) = ( Mat(2,3) * Mat(3,1) - Mat(2,1) * Mat(3,3) ) * sDet
INV33(2,2) = ( Mat(1,1) * Mat(3,3) - Mat(1,3) * Mat(3,1) ) * sDet
INV33(2,3) = ( Mat(1,3) * Mat(2,1) - Mat(1,1) * Mat(2,3) ) * sDet
INV33(3,1) = ( Mat(2,1) * Mat(3,2) - Mat(2,2) * Mat(3,1) ) * sDet
INV33(3,2) = ( Mat(1,2) * Mat(3,1) - Mat(1,1) * Mat(3,2) ) * sDet
INV33(3,3) = ( Mat(1,1) * Mat(2,2) - Mat(1,2) * Mat(2,1) ) * sDet

END FUNCTION INV33