インテル® Fortran コンパイラー XE 13.1 ユーザー・リファレンス・ガイド
Elemental Intrinsic Function (Generic): Returns the absolute spacing of model numbers near the argument value.
The result type and kind is the same as x. The result has the value b e-p. Parameters b, e, and p are defined in Model for Real Data. If the result value is outside of the real model range, the result is TINY( x).