101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/* ----------------------------------------------------------------------
|
|
* Project: CMSIS DSP Library
|
|
* Title: arm_var_f64.c
|
|
* Description: Variance of the elements of a floating-point vector
|
|
*
|
|
* $Date: 13 September 2021
|
|
* $Revision: V1.10.0
|
|
*
|
|
* Target Processor: Cortex-M and Cortex-A cores
|
|
* -------------------------------------------------------------------- */
|
|
/*
|
|
* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the License); you may
|
|
* not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "dsp/statistics_functions.h"
|
|
|
|
/**
|
|
@ingroup groupStats
|
|
*/
|
|
|
|
/**
|
|
@addtogroup variance
|
|
@{
|
|
*/
|
|
|
|
/**
|
|
@brief Variance of the elements of a floating-point vector.
|
|
@param[in] pSrc points to the input vector
|
|
@param[in] blockSize number of samples in input vector
|
|
@param[out] pResult variance value returned here
|
|
@return none
|
|
*/
|
|
void arm_var_f64(
|
|
const float64_t * pSrc,
|
|
uint32_t blockSize,
|
|
float64_t * pResult)
|
|
{
|
|
uint32_t blkCnt; /* Loop counter */
|
|
float64_t sum = 0.; /* Temporary result storage */
|
|
float64_t fSum = 0.;
|
|
float64_t fMean, fValue;
|
|
const float64_t * pInput = pSrc;
|
|
|
|
if (blockSize <= 1U)
|
|
{
|
|
*pResult = 0;
|
|
return;
|
|
}
|
|
|
|
/* Initialize blkCnt with number of samples */
|
|
blkCnt = blockSize;
|
|
|
|
while (blkCnt > 0U)
|
|
{
|
|
/* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */
|
|
|
|
sum += *pInput++;
|
|
|
|
/* Decrement loop counter */
|
|
blkCnt--;
|
|
}
|
|
|
|
/* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) / blockSize */
|
|
fMean = sum / (float64_t) blockSize;
|
|
|
|
pInput = pSrc;
|
|
|
|
/* Initialize blkCnt with number of samples */
|
|
blkCnt = blockSize;
|
|
|
|
while (blkCnt > 0U)
|
|
{
|
|
fValue = *pInput++ - fMean;
|
|
fSum += fValue * fValue;
|
|
|
|
/* Decrement loop counter */
|
|
blkCnt--;
|
|
}
|
|
|
|
/* Variance */
|
|
*pResult = fSum / (float64_t)(blockSize - 1.);
|
|
}
|
|
|
|
/**
|
|
@} end of variance group
|
|
*/
|