Mean [Statistics Functions]

Functions
void	arm_mean_f32 (float32_t *pSrc, uint32_t blockSize, float32_t *pResult)
void	arm_mean_q31 (q31_t *pSrc, uint32_t blockSize, q31_t *pResult)
void	arm_mean_q15 (q15_t *pSrc, uint32_t blockSize, q15_t *pResult)
void	arm_mean_q7 (q7_t *pSrc, uint32_t blockSize, q7_t *pResult)

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Detailed Description

Calculates the mean of the input vector. Mean is defined as the average of the elements in the vector. The underlying algorithm is used:

      
 	Result = (pSrc[0] + pSrc[1] + pSrc[2] + ... + pSrc[blockSize-1]) / blockSize;      
 

There are separate functions for floating-point, Q31, Q15, and Q7 data types.

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Function Documentation

void arm_mean_f32	(	float32_t *	pSrc,
		uint32_t	blockSize,
		float32_t *	pResult
	)

Mean value of a floating-point vector.

Parameters:

[in]	*pSrc	points to the input vector
[in]	blockSize	length of the input vector
[out]	*pResult	mean value returned here

Returns:

none.

Examples:

arm_class_marks_example_f32.c.

Definition at line 58 of file arm_mean_f32.c.

void arm_mean_q31	(	q31_t *	pSrc,
		uint32_t	blockSize,
		q31_t *	pResult
	)

Mean value of a Q31 vector.

Parameters:

[in]	*pSrc	points to the input vector
[in]	blockSize	length of the input vector
[out]	*pResult	mean value returned here

Returns:

none.

Scaling and Overflow Behavior:

The function is implemented using a 64-bit internal accumulator. The input is represented in 1.31 format and is accumulated in a 64-bit accumulator in 33.31 format. There is no risk of internal overflow with this approach, and the full precision of intermediate result is preserved. Finally, the accumulator is truncated to yield a result of 1.31 format.

Definition at line 55 of file arm_mean_q31.c.

void arm_mean_q15	(	q15_t *	pSrc,
		uint32_t	blockSize,
		q15_t *	pResult
	)

Mean value of a Q15 vector.

Parameters:

[in]	*pSrc	points to the input vector
[in]	blockSize	length of the input vector
[out]	*pResult	mean value returned here

Returns:

none.

Conditions for optimum performance

Input and output buffers should be aligned by 32-bit

Scaling and Overflow Behavior:

The function is implemented using a 32-bit internal accumulator. The input is represented in 1.15 format and is accumulated in a 32-bit accumulator in 17.15 format. There is no risk of internal overflow with this approach, and the full precision of intermediate result is preserved. Finally, the accumulator is saturated and truncated to yield a result of 1.15 format.

Definition at line 59 of file arm_mean_q15.c.

void arm_mean_q7	(	q7_t *	pSrc,
		uint32_t	blockSize,
		q7_t *	pResult
	)

Mean value of a Q7 vector.

Parameters:

[in]	*pSrc	points to the input vector
[in]	blockSize	length of the input vector
[out]	*pResult	mean value returned here

Returns:

none.

Conditions for optimum performance

Input and output buffers should be aligned by 32-bit

Scaling and Overflow Behavior:

The function is implemented using a 32-bit internal accumulator. The input is represented in 1.7 format and is accumulated in a 32-bit accumulator in 25.7 format. There is no risk of internal overflow with this approach, and the full precision of intermediate result is preserved. Finally, the accumulator is truncated to yield a result of 1.7 format.

Definition at line 59 of file arm_mean_q7.c.