gr_math.h File Reference
Go to the source code of this file.
|
Functions |
long | gr_gcd (long m, long n) |
int | gr_isnan (double value) |
int | gr_signbit (double x) |
float | gr_fast_atan2f (float y, float x) |
| Fast arc tangent using table lookup and linear interpolation.
|
Function Documentation
float gr_fast_atan2f |
( |
float |
y, |
|
|
float |
x | |
|
) |
| | |
Fast arc tangent using table lookup and linear interpolation.
- Parameters:
-
| y | component of input vector |
| x | component of input vector |
- Returns:
- float angle angle of vector (x, y) in radians
This function calculates the angle of the vector (x,y) based on a table lookup and linear interpolation. The table uses a 256 point table covering -45 to +45 degrees and uses symetry to determine the final angle value in the range of -180 to 180 degrees. Note that this function uses the small angle approximation for values close to zero. This routine calculates the arc tangent with an average error of +/- 0.045 degrees.
long gr_gcd |
( |
long |
m, |
|
|
long |
n | |
|
) |
| | |
int gr_isnan |
( |
double |
value |
) |
|
int gr_signbit |
( |
double |
x |
) |
|