Matrix Scale [Matrix Functions]

Functions
arm_status	arm_mat_scale_f32 (const arm_matrix_instance_f32 *pSrc, float32_t scale, arm_matrix_instance_f32 *pDst)
arm_status	arm_mat_scale_q31 (const arm_matrix_instance_q31 *pSrc, q31_t scaleFract, int32_t shift, arm_matrix_instance_q31 *pDst)
arm_status	arm_mat_scale_q15 (const arm_matrix_instance_q15 *pSrc, q15_t scaleFract, int32_t shift, arm_matrix_instance_q15 *pDst)

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Detailed Description

Multiplies a matrix by a scalar. This is accomplished by multiplying each element in the matrix by the scalar. For example:

Matrix Scaling of a 3 x 3 matrix

The function checks to make sure that the input and output matrices are of the same size.

In the fixed-point Q15 and Q31 functions, scale is represented by a fractional multiplication scaleFract and an arithmetic shift shift. The shift allows the gain of the scaling operation to exceed 1.0. The overall scale factor applied to the fixed-point data is

      
     scale = scaleFract * 2^shift.      
 

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Function Documentation

arm_status arm_mat_scale_f32	(	const arm_matrix_instance_f32 *	pSrc,
		float32_t	scale,
		arm_matrix_instance_f32 *	pDst
	)

Floating-point matrix scaling.

Parameters:

[in]	*pSrc	points to input matrix structure
[in]	scale	scale factor to be applied
[out]	*pDst	points to output matrix structure

Returns:

The function returns either ARM_MATH_SIZE_MISMATCH or ARM_MATH_SUCCESS based on the outcome of size checking.

Definition at line 64 of file arm_mat_scale_f32.c.

arm_status arm_mat_scale_q31	(	const arm_matrix_instance_q31 *	pSrc,
		q31_t	scaleFract,
		int32_t	shift,
		arm_matrix_instance_q31 *	pDst
	)

Q31 matrix scaling.

Parameters:

[in]	*pSrc	points to input matrix
[in]	scaleFract	fractional portion of the scale factor
[in]	shift	number of bits to shift the result by
[out]	*pDst	points to output matrix structure

Returns:

The function returns either ARM_MATH_SIZE_MISMATCH or ARM_MATH_SUCCESS based on the outcome of size checking.

Scaling and Overflow Behavior:

The input data *pSrc and scaleFract are in 1.31 format. These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.

Definition at line 52 of file arm_mat_scale_q31.c.

arm_status arm_mat_scale_q15	(	const arm_matrix_instance_q15 *	pSrc,
		q15_t	scaleFract,
		int32_t	shift,
		arm_matrix_instance_q15 *	pDst
	)

Q15 matrix scaling.

Parameters:

[in]	*pSrc	points to input matrix
[in]	scaleFract	fractional portion of the scale factor
[in]	shift	number of bits to shift the result by
[out]	*pDst	points to output matrix structure

Returns:

The function returns either ARM_MATH_SIZE_MISMATCH or ARM_MATH_SUCCESS based on the outcome of size checking.

Conditions for optimum performance

Input and output buffers should be aligned by 32-bit

Scaling and Overflow Behavior:

The input data *pSrc and scaleFract are in 1.15 format. These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.

Definition at line 56 of file arm_mat_scale_q15.c.