NMSIS-DSP  Version 1.2.0
NMSIS DSP Software Library
Fast Math Functions

This set of functions provides a fast approximation to sine, cosine, and square root. As compared to most of the other functions in the NMSIS math library, the fast math functions operate on individual values and not arrays. There are separate functions for Q15, Q31, and floating-point data. More...

Modules

 ArcTan2
 Computing Arc tangent only using the ratio y/x is not enough to determine the angle since there is an indeterminacy. Opposite quadrants are giving the same ratio.
 
 Cosine
 Computes the trigonometric cosine function using a combination of table lookup and linear interpolation. There are separate functions for Q15, Q31, and floating-point data types. The input to the floating-point version is in radians while the fixed-point Q15 and Q31 have a scaled input with the range [0 +0.9999] mapping to [0 2*pi). The fixed-point range is chosen so that a value of 2*pi wraps around to 0.
 
 Fixed point division
 
 Sine
 Computes the trigonometric sine function using a combination of table lookup and linear interpolation. There are separate functions for Q15, Q31, and floating-point data types. The input to the floating-point version is in radians while the fixed-point Q15 and Q31 have a scaled input with the range [0 +0.9999] mapping to [0 2*pi). The fixed-point range is chosen so that a value of 2*pi wraps around to 0.
 
 Vector Exponential
 Compute the exp values of a vector of samples.
 
 Vector Log
 Compute the log values of a vector of samples.
 
 Square Root
 Computes the square root of a number. There are separate functions for Q15, Q31, and floating-point data types. The square root function is computed using the Newton-Raphson algorithm. This is an iterative algorithm of the form:
 

Detailed Description

This set of functions provides a fast approximation to sine, cosine, and square root. As compared to most of the other functions in the NMSIS math library, the fast math functions operate on individual values and not arrays. There are separate functions for Q15, Q31, and floating-point data.