# Atan

Computes inverse tangent of vector elements.

## Syntax

Fortran:

call vsatan( n, a, y )

call vdatan( n, a, y )

call vcatan( n, a, y )

call vzatan( n, a, y )

C:

vsAtan( n, a, y );

vdAtan( n, a, y );

vcAtan( n, a, y );

vzAtan( n, a, y );

## Input Parameters

Name | Type | Description
--- | --- | ---
n | FORTRAN: INTEGER, INTENT(IN) C: int | Specifies the number of elements to be calculated.
a | FORTRAN: REAL, INTENT(IN) for vsatan DOUBLE PRECISION, INTENT(IN) for vdatan COMPLEX, INTENT(IN) for vcatan DOUBLE COMPLEX, INTENT(IN) for vzatan C: const float* for vsAtan const double* for vdAsin const MKL_Complex8* for vcAtan const MKL_Complex16* for vzAsin | FORTRAN: Array, specifies the input vector a. C: Pointer to an array that contains the input vector a.

## Output Parameters

Name | Type | Description
--- | --- | ---
y | FORTRAN: REAL for vsatan DOUBLE PRECISION for vdatan COMPLEX for vcatan DOUBLE COMPLEX for vzatan C: float* for vsAtan double* for vdAtan MKL_Complex8* for vcAtan MKL_Complex16* for vzAtan | FORTRAN: Array, specifies the output vector y. C: Pointer to an array that contains the output vector y.

Parent topic: Trigonometric Functions