Matrix Scale

Functions
arm_status	arm_mat_scale_f16 (const arm_matrix_instance_f16 *pSrc, float16_t scale, arm_matrix_instance_f16 *pDst)
	Floating-point matrix scaling. More...
arm_status	arm_mat_scale_f32 (const arm_matrix_instance_f32 *pSrc, float32_t scale, arm_matrix_instance_f32 *pDst)
	Floating-point matrix scaling. More...
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. More...
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. More...

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

\[ \begin{pmatrix} a_{1,1} & a_{1,2} & a_{1,3} \\ a_{2,1} & a_{2,2} & a_{2,3} \\ a_{3,1} & a_{3,2} & a_{3,3} \\ \end{pmatrix} K = \begin{pmatrix} K a_{1,1} & K a_{1,2} & K a_{1,3} \\ K a_{2,1} & K a_{2,2} & K a_{2,3} \\ K a_{3,1} & K a_{3,2} & K a_{3,3} \\ \end{pmatrix} \]

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.

Function Documentation

arm_mat_scale_f16()

arm_status arm_mat_scale_f16	(	const arm_matrix_instance_f16 *	pSrc,
		float16_t	scale,
		arm_matrix_instance_f16 *	pDst
	)

Parameters

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

Returns

execution status

• ARM_MATH_SUCCESS : Operation successful
• ARM_MATH_SIZE_MISMATCH : Matrix size check failed

arm_mat_scale_f32()

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

Parameters

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

Returns

execution status

• ARM_MATH_SUCCESS : Operation successful
• ARM_MATH_SIZE_MISMATCH : Matrix size check failed

arm_mat_scale_q15()

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

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

execution status

• ARM_MATH_SUCCESS : Operation successful
• ARM_MATH_SIZE_MISMATCH : Matrix size check failed

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.

arm_mat_scale_q31()

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

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

execution status

• ARM_MATH_SUCCESS : Operation successful
• ARM_MATH_SIZE_MISMATCH : Matrix size check failed

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 which is shifted with saturation to 1.31 format.