atan.3Cg

Langue: en

Version: 345624 (ubuntu - 24/10/10)

Section: 3 (Bibliothèques de fonctions)

NAME

atan - returns arctangent of scalars and vectors.

SYNOPSIS

   float  atan(float a);
   float1 atan(float1 a);
   float2 atan(float2 a);
   float3 atan(float3 a);
   float4 atan(float4 a);
 
 
 
   half   atan(half a);
   half1  atan(half1 a);
   half2  atan(half2 a);
   half3  atan(half3 a);
   half4  atan(half4 a);
 
 
 
   fixed  atan(fixed a);
   fixed1 atan(fixed1 a);
   fixed2 atan(fixed2 a);
   fixed3 atan(fixed3 a);
   fixed4 atan(fixed4 a);
 
 
 

PARAMETERS


a
Vector or scalar of which to determine the arctangent.

DESCRIPTION

Returns the arctangent of x in the range of -pi/2 to pi/2 radians.

For vectors, the returned vector contains the arctangent of each element of the input vector.

REFERENCE IMPLEMENTATION

atan for a float scalar could be implemented like this.
   float atan(float x) {
       return atan2(x, float(1));
   }
 
 
 
atan2 is typically implemented as an approximation.

PROFILE SUPPORT

atan is supported in all profiles but fp20.

SEE ALSO

abs, acos, asin, atan2. sqrt, tan