EPSILON(X)

Purpose

Returns a positive model number that is almost negligible compared to unity in the model representing numbers of the same type and kind type parameter as the argument.

Class

Inquiry function

Argument type and attributes

X: An INTENT(IN) REAL. The corresponding actual argument can be scalar or array valued.

Result type and attributes

Scalar of the same type and kind type parameter as X.

Result value

The result is

2.0ei0^{1 - DIGITS(X)}

where ei is the exponent indicator (E, D, or Q) depending on the type of X:

type                      EPSILON(X)
----                      ----------
real(4)                   02E0 ** (-23)
real(8)                   02D0 ** (-52)
real(16)                  02Q0 ** (-105)

Examples

IBM extension begins EPSILON (X) = 1.1920929E-07 for X of type real(4). See Real data model. IBM extension ends