| 1 | /* ----------------------------------------------------------------------
|
|---|
| 2 | * Project: CMSIS DSP Library
|
|---|
| 3 | * Title: arm_rms_f32.c
|
|---|
| 4 | * Description: Root mean square value of an array of F32 type
|
|---|
| 5 | *
|
|---|
| 6 | * $Date: 27. January 2017
|
|---|
| 7 | * $Revision: V.1.5.1
|
|---|
| 8 | *
|
|---|
| 9 | * Target Processor: Cortex-M cores
|
|---|
| 10 | * -------------------------------------------------------------------- */
|
|---|
| 11 | /*
|
|---|
| 12 | * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
|
|---|
| 13 | *
|
|---|
| 14 | * SPDX-License-Identifier: Apache-2.0
|
|---|
| 15 | *
|
|---|
| 16 | * Licensed under the Apache License, Version 2.0 (the License); you may
|
|---|
| 17 | * not use this file except in compliance with the License.
|
|---|
| 18 | * You may obtain a copy of the License at
|
|---|
| 19 | *
|
|---|
| 20 | * www.apache.org/licenses/LICENSE-2.0
|
|---|
| 21 | *
|
|---|
| 22 | * Unless required by applicable law or agreed to in writing, software
|
|---|
| 23 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT
|
|---|
| 24 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|---|
| 25 | * See the License for the specific language governing permissions and
|
|---|
| 26 | * limitations under the License.
|
|---|
| 27 | */
|
|---|
| 28 |
|
|---|
| 29 | #include "arm_math.h"
|
|---|
| 30 |
|
|---|
| 31 | /**
|
|---|
| 32 | * @ingroup groupStats
|
|---|
| 33 | */
|
|---|
| 34 |
|
|---|
| 35 | /**
|
|---|
| 36 | * @defgroup RMS Root mean square (RMS)
|
|---|
| 37 | *
|
|---|
| 38 | *
|
|---|
| 39 | * Calculates the Root Mean Sqaure of the elements in the input vector.
|
|---|
| 40 | * The underlying algorithm is used:
|
|---|
| 41 | *
|
|---|
| 42 | * <pre>
|
|---|
| 43 | * Result = sqrt(((pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]) / blockSize));
|
|---|
| 44 | * </pre>
|
|---|
| 45 | *
|
|---|
| 46 | * There are separate functions for floating point, Q31, and Q15 data types.
|
|---|
| 47 | */
|
|---|
| 48 |
|
|---|
| 49 | /**
|
|---|
| 50 | * @addtogroup RMS
|
|---|
| 51 | * @{
|
|---|
| 52 | */
|
|---|
| 53 |
|
|---|
| 54 |
|
|---|
| 55 | /**
|
|---|
| 56 | * @brief Root Mean Square of the elements of a floating-point vector.
|
|---|
| 57 | * @param[in] *pSrc points to the input vector
|
|---|
| 58 | * @param[in] blockSize length of the input vector
|
|---|
| 59 | * @param[out] *pResult rms value returned here
|
|---|
| 60 | * @return none.
|
|---|
| 61 | *
|
|---|
| 62 | */
|
|---|
| 63 |
|
|---|
| 64 | void arm_rms_f32(
|
|---|
| 65 | float32_t * pSrc,
|
|---|
| 66 | uint32_t blockSize,
|
|---|
| 67 | float32_t * pResult)
|
|---|
| 68 | {
|
|---|
| 69 | float32_t sum = 0.0f; /* Accumulator */
|
|---|
| 70 | float32_t in; /* Tempoprary variable to store input value */
|
|---|
| 71 | uint32_t blkCnt; /* loop counter */
|
|---|
| 72 |
|
|---|
| 73 | #if defined (ARM_MATH_DSP)
|
|---|
| 74 | /* Run the below code for Cortex-M4 and Cortex-M3 */
|
|---|
| 75 |
|
|---|
| 76 | /* loop Unrolling */
|
|---|
| 77 | blkCnt = blockSize >> 2U;
|
|---|
| 78 |
|
|---|
| 79 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
|
|---|
| 80 | ** a second loop below computes the remaining 1 to 3 samples. */
|
|---|
| 81 | while (blkCnt > 0U)
|
|---|
| 82 | {
|
|---|
| 83 | /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
|
|---|
| 84 | /* Compute sum of the squares and then store the result in a temporary variable, sum */
|
|---|
| 85 | in = *pSrc++;
|
|---|
| 86 | sum += in * in;
|
|---|
| 87 | in = *pSrc++;
|
|---|
| 88 | sum += in * in;
|
|---|
| 89 | in = *pSrc++;
|
|---|
| 90 | sum += in * in;
|
|---|
| 91 | in = *pSrc++;
|
|---|
| 92 | sum += in * in;
|
|---|
| 93 |
|
|---|
| 94 | /* Decrement the loop counter */
|
|---|
| 95 | blkCnt--;
|
|---|
| 96 | }
|
|---|
| 97 |
|
|---|
| 98 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
|
|---|
| 99 | ** No loop unrolling is used. */
|
|---|
| 100 | blkCnt = blockSize % 0x4U;
|
|---|
| 101 |
|
|---|
| 102 | #else
|
|---|
| 103 | /* Run the below code for Cortex-M0 */
|
|---|
| 104 |
|
|---|
| 105 | /* Loop over blockSize number of values */
|
|---|
| 106 | blkCnt = blockSize;
|
|---|
| 107 |
|
|---|
| 108 | #endif /* #if defined (ARM_MATH_DSP) */
|
|---|
| 109 |
|
|---|
| 110 | while (blkCnt > 0U)
|
|---|
| 111 | {
|
|---|
| 112 | /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
|
|---|
| 113 | /* Compute sum of the squares and then store the results in a temporary variable, sum */
|
|---|
| 114 | in = *pSrc++;
|
|---|
| 115 | sum += in * in;
|
|---|
| 116 |
|
|---|
| 117 | /* Decrement the loop counter */
|
|---|
| 118 | blkCnt--;
|
|---|
| 119 | }
|
|---|
| 120 |
|
|---|
| 121 | /* Compute Rms and store the result in the destination */
|
|---|
| 122 | arm_sqrt_f32(sum / (float32_t) blockSize, pResult);
|
|---|
| 123 | }
|
|---|
| 124 |
|
|---|
| 125 | /**
|
|---|
| 126 | * @} end of RMS group
|
|---|
| 127 | */
|
|---|
