EPSILON intrinsic function
Standard: F77 F90 F95 F2003 F2008
 Example Program

X : Real, scalar or array, any kind;
Result : Scalar, same type and kind as X.

This function returns the “model number” that is almost negligible with respect to 1.0 for the type and kind of X. This value is equal to REAL(RADIX(X),KIND(X))**(-DIGITS(X)). Adding EPSILON(X) to 1.0 (with the kind of X) will always produce a value greater than 1.0.

This is an inquiry function, so X need not be defined; indeed, it is permitted to be disassociated, unallocated, or absent.

The model for real type is that it may be zero or a signed fraction between 1 and 1/RADIX(X) consisting of DIGITS(X) digits, multiplied by an exponent RADIX(X)**e with MINEXPONENT(X)eMAXEXPONENT(X).

DIGITS intrinsic function, HUGE intrinsic function, MAXEXPONENT intrinsic function, MINEXPONENT intrinsic function, PRECISION intrinsic function, RADIX intrinsic function, REAL type, TINY intrinsic function.