/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_power_f32.c * Description: Sum of the squares of the elements of a floating-point vector * * $Date: 18. March 2019 * $Revision: V1.6.0 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* * Copyright (C) 2010-2019 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 "arm_math.h" /** @ingroup groupStats */ /** @defgroup power Power Calculates the sum of the squares of the elements in the input vector. The underlying algorithm is used:
      Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];
  
There are separate functions for floating point, Q31, Q15, and Q7 data types. */ /** @addtogroup power @{ */ /** @brief Sum of the squares 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 sum of the squares value returned here @return none */ void arm_power_f32( const float32_t * pSrc, uint32_t blockSize, float32_t * pResult) { uint32_t blkCnt; /* Loop counter */ float32_t sum = 0.0f; /* Temporary result storage */ float32_t in; /* Temporary variable to store input value */ #if defined (ARM_MATH_LOOPUNROLL) /* Loop unrolling: Compute 4 outputs at a time */ blkCnt = blockSize >> 2U; while (blkCnt > 0U) { /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */ /* Compute Power and store result in a temporary variable, sum. */ in = *pSrc++; sum += in * in; in = *pSrc++; sum += in * in; in = *pSrc++; sum += in * in; in = *pSrc++; sum += in * in; /* Decrement loop counter */ blkCnt--; } /* Loop unrolling: Compute remaining outputs */ blkCnt = blockSize % 0x4U; #else /* Initialize blkCnt with number of samples */ blkCnt = blockSize; #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ while (blkCnt > 0U) { /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */ /* Compute Power and store result in a temporary variable, sum. */ in = *pSrc++; sum += in * in; /* Decrement loop counter */ blkCnt--; } /* Store result to destination */ *pResult = sum; } /** @} end of power group */