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 Intrinsic Function (Generic): Returns the nearest different number (representable on the processor) in a given direction.
The result type and kind is the same as x. The result has a value equal to the machine representable number that is different from and nearest to x, in the direction of the infinity with the same sign as s.
If 3.0 and 2.0 are REAL(4) values, NEAREST (3.0, 2.0) has the value 3 + 2 -22, which equals approximately 3.0000002. (For more information on the model for REAL(4), see Model for Real Data.
The following shows another example:
REAL(4) r1
REAL(8) r2, result
r1 = 3.0
result = NEAREST (r1, -2.0)
WRITE(*,*) result ! writes 2.999999761581421
! When finding nearest to REAL(8), can't see
! the difference unless output in HEX
r2 = 111502.07D0
result = NEAREST(r2, 2.0)
WRITE(*,'(1x,Z16)') result ! writes 40FB38E11EB851ED
result = NEAREST(r2, -2.0)
WRITE(*,'(1x,Z16)') result ! writes 40FB38E11EB851EB
END