インテル® Fortran コンパイラー 14.0 ユーザー・リファレンス・ガイド
Elemental Module Intrinsic Function (Generic): Returns the result value from a remainder operation. This is equivalent to the IEEE rem function.
The result type is real with the kind type parameter of whichever argument has greater precision.
Regardless of the rounding mode, the result value is x - y*N, where N is the integer nearest to the value x / y. If |N – x / y | = 1/2, N is even. If the result value is zero, the sign is the same as x.