Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

ID 767251
Date 3/22/2024
Public

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Document Table of Contents

ATAN

Elemental Intrinsic Function (Generic): Produces the arctangent of an argument in radians.

result = ATAN (x)

result = ATAN (y,x)

y

(Input) Must be of type real.

x

(Input) If y appears, x must be of type real with the same kind type parameter as y.

If y has the value zero, x must not have the value zero.

If y does not appear, x must be of type real or complex.

Results

The result type and kind are the same as x.

If y appears, the result is the same as the result of ATAN2 (y, x).

If y does not appear, the real part of the result is expressed in radians and lies in the range -pi/2 <= ATAN (x) <= pi/2.

Specific Name

Argument Type

Result Type

ATAN

REAL(4)

REAL(4)

DATAN

REAL(8)

REAL(8)

QATAN

REAL(16)

REAL(16)

Example

ATAN (1.5874993) has the value 1.008666.

ATAN (2.679676, 1.0) has the value 1.213623.