DSP/Source/StatisticsFunctions/arm_absmax_f64.c

/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_absmax_f64.c
 * Description:  Maximum value of absolute values 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 AbsMax
  @{
 */

/**
  @brief         Maximum value of absolute values 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    maximum value returned here
  @param[out]    pIndex     index of maximum value returned here
  @return        none
 */
void arm_absmax_f64(
  const float64_t * pSrc,
        uint32_t blockSize,
        float64_t * pResult,
        uint32_t * pIndex)
{
        float64_t maxVal, out;                         /* Temporary variables to store the output value. */
        uint32_t blkCnt, outIndex;                     /* Loop counter */



  /* Initialise index value to zero. */
  outIndex = 0U;

  /* Load first input value that act as reference value for comparision */
  out = fabs(*pSrc++);

  /* Initialize blkCnt with number of samples */
  blkCnt = (blockSize - 1U);

  while (blkCnt > 0U)
  {
    /* Initialize maxVal to the next consecutive values one by one */
    maxVal = fabs(*pSrc++);

    /* compare for the maximum value */
    if (out < maxVal)
    {
      /* Update the maximum value and it's index */
      out = maxVal;
      outIndex = blockSize - blkCnt;
    }

    /* Decrement loop counter */
    blkCnt--;
  }

  /* Store the maximum value and it's index into destination pointers */
  *pResult = out;
  *pIndex = outIndex;
}

/**
  @} end of AbsMax group
 */