CMSIS DSP Software Library: Matrix Scale

Functions

# 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)

## 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.

## 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 75 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 63 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.

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 63 of file arm_mat_scale_q15.c.

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