mbed official / mbed-dsp

CMSIS DSP library

Dependents:   performance_timer Surfboard_ gps2rtty Capstone ... more

Embed: (wiki syntax)

« Back to documentation index

Vector Dot Product
Functions

Vector Dot Product
[Basic Math Functions]

Computes the dot product of two vectors. More...

Functions

void arm_dot_prod_f32 (float32_t *pSrcA, float32_t *pSrcB, uint32_t blockSize, float32_t *result)
 Dot product of floating-point vectors.
void arm_dot_prod_q15 (q15_t *pSrcA, q15_t *pSrcB, uint32_t blockSize, q63_t *result)
 Dot product of Q15 vectors.
void arm_dot_prod_q31 (q31_t *pSrcA, q31_t *pSrcB, uint32_t blockSize, q63_t *result)
 Dot product of Q31 vectors.
void arm_dot_prod_q7 (q7_t *pSrcA, q7_t *pSrcB, uint32_t blockSize, q31_t *result)
 Dot product of Q7 vectors.

Detailed Description

Computes the dot product of two vectors.

The vectors are multiplied element-by-element and then summed.

     sum = pSrcA[0]*pSrcB[0] + pSrcA[1]*pSrcB[1] + ... + pSrcA[blockSize-1]*pSrcB[blockSize-1]

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

Function Documentation

void arm_dot_prod_f32 ( float32_t *  pSrcA,
float32_t *  pSrcB,
uint32_t  blockSize,
float32_t *  result 
)

Dot product of floating-point vectors.

Parameters:
[in]*pSrcApoints to the first input vector
[in]*pSrcBpoints to the second input vector
[in]blockSizenumber of samples in each vector
[out]*resultoutput result returned here
Returns:
none.

Definition at line 75 of file arm_dot_prod_f32.c.

void arm_dot_prod_q15 ( q15_t *  pSrcA,
q15_t *  pSrcB,
uint32_t  blockSize,
q63_t *  result 
)

Dot product of Q15 vectors.

Parameters:
[in]*pSrcApoints to the first input vector
[in]*pSrcBpoints to the second input vector
[in]blockSizenumber of samples in each vector
[out]*resultoutput result returned here
Returns:
none.

Scaling and Overflow Behavior:

The intermediate multiplications are in 1.15 x 1.15 = 2.30 format and these results are added to a 64-bit accumulator in 34.30 format. Nonsaturating additions are used and given that there are 33 guard bits in the accumulator there is no risk of overflow. The return result is in 34.30 format.

Definition at line 69 of file arm_dot_prod_q15.c.

void arm_dot_prod_q31 ( q31_t *  pSrcA,
q31_t *  pSrcB,
uint32_t  blockSize,
q63_t *  result 
)

Dot product of Q31 vectors.

Parameters:
[in]*pSrcApoints to the first input vector
[in]*pSrcBpoints to the second input vector
[in]blockSizenumber of samples in each vector
[out]*resultoutput result returned here
Returns:
none.

Scaling and Overflow Behavior:

The intermediate multiplications are in 1.31 x 1.31 = 2.62 format and these are truncated to 2.48 format by discarding the lower 14 bits. The 2.48 result is then added without saturation to a 64-bit accumulator in 16.48 format. There are 15 guard bits in the accumulator and there is no risk of overflow as long as the length of the vectors is less than 2^16 elements. The return result is in 16.48 format.

Definition at line 70 of file arm_dot_prod_q31.c.

void arm_dot_prod_q7 ( q7_t *  pSrcA,
q7_t *  pSrcB,
uint32_t  blockSize,
q31_t *  result 
)

Dot product of Q7 vectors.

Parameters:
[in]*pSrcApoints to the first input vector
[in]*pSrcBpoints to the second input vector
[in]blockSizenumber of samples in each vector
[out]*resultoutput result returned here
Returns:
none.

Scaling and Overflow Behavior:

The intermediate multiplications are in 1.7 x 1.7 = 2.14 format and these results are added to an accumulator in 18.14 format. Nonsaturating additions are used and there is no danger of wrap around as long as the vectors are less than 2^18 elements long. The return result is in 18.14 format.

Definition at line 69 of file arm_dot_prod_q7.c.

Generated on Tue Jul 12 2022 11:59:19 by  doxygen 1.7.2