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Using and Porting GNU Fortran

8.11.9.2 Abs Intrinsic

Abs(A)

Abs: INTEGER or REAL function. The exact type depends on that of argument A---if A is COMPLEX, this function's type is REAL with the same `KIND=' value as the type of A. Otherwise, this function's type is the same as that of A.

A: INTEGER, REAL, or COMPLEX; scalar; INTENT(IN).

Intrinsic groups: (standard FORTRAN 77).

Description:

Returns the absolute value of A.

If A is type COMPLEX, the absolute value is computed as:

SQRT(REALPART(A)**2+IMAGPART(A)**2)

Otherwise, it is computed by negating A if it is negative, or returning A.

See section 8.11.9.227 Sign Intrinsic, for how to explicitly compute the positive or negative form of the absolute value of an expression.