ALMOSTEQUAL Function

private function ALMOSTEQUAL(x, y) result(AlmostEqual)

Determines if two REAL(wp) numbers are equal up to a specified tolerance (=PP_RealTolerance, normaly set to machine precision) Takes into account that x,y are located in-between [-1;1] Based on Algorithm 139, Kopriva

Arguments

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

(IN) first scalar to be compared
real(kind=wp), intent(in) :: y

(IN) second scalar to be compared

Return Value logical

(OUT) TRUE if |x-y| < 2*PP_RealTolerance


Called by

proc~~almostequal~~CalledByGraph proc~almostequal ALMOSTEQUAL proc~lagrangeinterpolationpolys LagrangeInterpolationPolys proc~lagrangeinterpolationpolys->proc~almostequal

Source Code

FUNCTION ALMOSTEQUAL(x,y)
IMPLICIT NONE
!----------------------------------------------------------------------------------------------------------------------------------
! INPUT/OUTPUT VARIABLES
REAL(wp),INTENT(IN) :: x                !! (IN)  first scalar to be compared
REAL(wp),INTENT(IN) :: y                !! (IN)  second scalar to be compared
LOGICAL         :: AlmostEqual      !! (OUT) TRUE if |x-y| < 2*PP_RealTolerance
!----------------------------------------------------------------------------------------------------------------------------------
! LOCAL VARIABLES
!==================================================================================================================================
AlmostEqual=.FALSE.
IF((x.EQ.0.0_wp).OR.(y.EQ.0.0_wp)) THEN
  IF(ABS(x-y).LE.2.0_wp*PP_RealTolerance) AlmostEqual=.TRUE.
ELSE ! x, y not zero
  IF((ABS(x-y).LE.PP_RealTolerance*ABS(x)).AND.((ABS(x-y).LE.PP_RealTolerance*ABS(y)))) AlmostEqual=.TRUE.
END IF ! x,y zero
END FUNCTION ALMOSTEQUAL