IBM Extension

ATAN2D(Y, X)

Purpose

Arctangent (inverse tangent) function. The result is the principal value of the nonzero complex number (X, Y) formed by the real arguments Y and X.

Class

Elemental function

Argument type and attributes

Y
must be of type real.
X
must be of the same type and kind type parameter as Y. If Y has the value zero, X must not have the value zero.

Result type and attributes

Same as X.

Result value

Examples

ATAN2D (1.5574077, 1.0) has the value 57.295780181 (approximately).

Given that:

Y = |  1.0   1.0 |   X = | -1.0   1.0 |
    | -1.0  -1.0 |       | -1.0   1.0 |

then the value of ATAN2D(Y,X) is:

ATAN2D(Y,X) =  |  135.0000000   45.00000000 |
               | -135.0000000  -45.00000000 |

Specific Name Argument Type Result Type Pass As Arg?
ATAN2D default real default real yes
DATAN2D double precision real double precision real yes
QATAN2D REAL(16) REAL(16) yes
End of IBM Extension