CMSISDSP
Version 1.5.2
CMSIS DSP Software Library

Functions  
void  arm_var_f32 (float32_t *pSrc, uint32_t blockSize, float32_t *pResult) 
Variance of the elements of a floatingpoint vector. More...  
void  arm_var_q15 (q15_t *pSrc, uint32_t blockSize, q15_t *pResult) 
Variance of the elements of a Q15 vector. More...  
void  arm_var_q31 (q31_t *pSrc, uint32_t blockSize, q31_t *pResult) 
Variance of the elements of a Q31 vector. More...  
Calculates the variance of the elements in the input vector. The underlying algorithm used is the direct method sometimes referred to as the twopass method:
Result = sum(element  meanOfElements)^2) / numElement  1
where, meanOfElements = ( pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize1] ) / blockSize
There are separate functions for floating point, Q31, and Q15 data types.
[in]  *pSrc  points to the input vector 
[in]  blockSize  length of the input vector 
[out]  *pResult  variance value returned here 
Scaling and Overflow Behavior:
References __SIMD32, __SMLALD(), and blockSize.
[in]  *pSrc  points to the input vector 
[in]  blockSize  length of the input vector 
[out]  *pResult  variance value returned here 
Scaling and Overflow Behavior:
References blockSize.