Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

StatisticsFunctions/arm_var_f32.c@0:3d9c67d97d6f, 2014-07-28 (annotated)

Committer:
emh203
Date:
Mon Jul 28 15:03:15 2014 +0000
Revision:
0:3d9c67d97d6f
1st working commit.   Had to remove arm_bitreversal2.s     arm_cfft_f32.c and arm_rfft_fast_f32.c.    The .s will not assemble.      For now I removed these functions so we could at least have a library for the other functions.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emh203 0:3d9c67d97d6f 1 /* ----------------------------------------------------------------------
emh203 0:3d9c67d97d6f 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emh203 0:3d9c67d97d6f 3 *
emh203 0:3d9c67d97d6f 4 * $Date: 12. March 2014
emh203 0:3d9c67d97d6f 5 * $Revision: V1.4.3
emh203 0:3d9c67d97d6f 6 *
emh203 0:3d9c67d97d6f 7 * Project: CMSIS DSP Library
emh203 0:3d9c67d97d6f 8 * Title: arm_var_f32.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Variance of the elements of a floating-point vector.
emh203 0:3d9c67d97d6f 11 *
emh203 0:3d9c67d97d6f 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 13 *
emh203 0:3d9c67d97d6f 14 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 15 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 16 * are met:
emh203 0:3d9c67d97d6f 17 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 18 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 19 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 20 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 21 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 22 * distribution.
emh203 0:3d9c67d97d6f 23 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 24 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 25 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 26 *
emh203 0:3d9c67d97d6f 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 38 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 39 * ---------------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 40
emh203 0:3d9c67d97d6f 41 #include "arm_math.h"
emh203 0:3d9c67d97d6f 42
emh203 0:3d9c67d97d6f 43 /**
emh203 0:3d9c67d97d6f 44 * @ingroup groupStats
emh203 0:3d9c67d97d6f 45 */
emh203 0:3d9c67d97d6f 46
emh203 0:3d9c67d97d6f 47 /**
emh203 0:3d9c67d97d6f 48 * @defgroup variance Variance
emh203 0:3d9c67d97d6f 49 *
emh203 0:3d9c67d97d6f 50 * Calculates the variance of the elements in the input vector.
emh203 0:3d9c67d97d6f 51 * The underlying algorithm is used:
emh203 0:3d9c67d97d6f 52 *
emh203 0:3d9c67d97d6f 53 * <pre>
emh203 0:3d9c67d97d6f 54 * Result = (sumOfSquares - sum<sup>2</sup> / blockSize) / (blockSize - 1)
emh203 0:3d9c67d97d6f 55 *
emh203 0:3d9c67d97d6f 56 * where, sumOfSquares = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]
emh203 0:3d9c67d97d6f 57 *
emh203 0:3d9c67d97d6f 58 * sum = pSrc[0] + pSrc[1] + pSrc[2] + ... + pSrc[blockSize-1]
emh203 0:3d9c67d97d6f 59 * </pre>
emh203 0:3d9c67d97d6f 60 *
emh203 0:3d9c67d97d6f 61 * There are separate functions for floating point, Q31, and Q15 data types.
emh203 0:3d9c67d97d6f 62 */
emh203 0:3d9c67d97d6f 63
emh203 0:3d9c67d97d6f 64 /**
emh203 0:3d9c67d97d6f 65 * @addtogroup variance
emh203 0:3d9c67d97d6f 66 * @{
emh203 0:3d9c67d97d6f 67 */
emh203 0:3d9c67d97d6f 68
emh203 0:3d9c67d97d6f 69
emh203 0:3d9c67d97d6f 70 /**
emh203 0:3d9c67d97d6f 71 * @brief Variance of the elements of a floating-point vector.
emh203 0:3d9c67d97d6f 72 * @param[in] *pSrc points to the input vector
emh203 0:3d9c67d97d6f 73 * @param[in] blockSize length of the input vector
emh203 0:3d9c67d97d6f 74 * @param[out] *pResult variance value returned here
emh203 0:3d9c67d97d6f 75 * @return none.
emh203 0:3d9c67d97d6f 76 *
emh203 0:3d9c67d97d6f 77 */
emh203 0:3d9c67d97d6f 78
emh203 0:3d9c67d97d6f 79
emh203 0:3d9c67d97d6f 80 void arm_var_f32(
emh203 0:3d9c67d97d6f 81 float32_t * pSrc,
emh203 0:3d9c67d97d6f 82 uint32_t blockSize,
emh203 0:3d9c67d97d6f 83 float32_t * pResult)
emh203 0:3d9c67d97d6f 84 {
emh203 0:3d9c67d97d6f 85
emh203 0:3d9c67d97d6f 86 float32_t sum = 0.0f; /* Temporary result storage */
emh203 0:3d9c67d97d6f 87 float32_t sumOfSquares = 0.0f; /* Sum of squares */
emh203 0:3d9c67d97d6f 88 float32_t in; /* input value */
emh203 0:3d9c67d97d6f 89 uint32_t blkCnt; /* loop counter */
emh203 0:3d9c67d97d6f 90
emh203 0:3d9c67d97d6f 91 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 92
emh203 0:3d9c67d97d6f 93 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 94
emh203 0:3d9c67d97d6f 95 float32_t meanOfSquares, mean, squareOfMean; /* Temporary variables */
emh203 0:3d9c67d97d6f 96
emh203 0:3d9c67d97d6f 97 if(blockSize == 1)
emh203 0:3d9c67d97d6f 98 {
emh203 0:3d9c67d97d6f 99 *pResult = 0;
emh203 0:3d9c67d97d6f 100 return;
emh203 0:3d9c67d97d6f 101 }
emh203 0:3d9c67d97d6f 102
emh203 0:3d9c67d97d6f 103 /*loop Unrolling */
emh203 0:3d9c67d97d6f 104 blkCnt = blockSize >> 2u;
emh203 0:3d9c67d97d6f 105
emh203 0:3d9c67d97d6f 106 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emh203 0:3d9c67d97d6f 107 ** a second loop below computes the remaining 1 to 3 samples. */
emh203 0:3d9c67d97d6f 108 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 109 {
emh203 0:3d9c67d97d6f 110 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 111 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 112 * and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 113 in = *pSrc++;
emh203 0:3d9c67d97d6f 114 sum += in;
emh203 0:3d9c67d97d6f 115 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 116 in = *pSrc++;
emh203 0:3d9c67d97d6f 117 sum += in;
emh203 0:3d9c67d97d6f 118 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 119 in = *pSrc++;
emh203 0:3d9c67d97d6f 120 sum += in;
emh203 0:3d9c67d97d6f 121 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 122 in = *pSrc++;
emh203 0:3d9c67d97d6f 123 sum += in;
emh203 0:3d9c67d97d6f 124 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 125
emh203 0:3d9c67d97d6f 126 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 127 blkCnt--;
emh203 0:3d9c67d97d6f 128 }
emh203 0:3d9c67d97d6f 129
emh203 0:3d9c67d97d6f 130 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emh203 0:3d9c67d97d6f 131 ** No loop unrolling is used. */
emh203 0:3d9c67d97d6f 132 blkCnt = blockSize % 0x4u;
emh203 0:3d9c67d97d6f 133
emh203 0:3d9c67d97d6f 134 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 135 {
emh203 0:3d9c67d97d6f 136 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 137 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 138 * and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 139 in = *pSrc++;
emh203 0:3d9c67d97d6f 140 sum += in;
emh203 0:3d9c67d97d6f 141 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 142
emh203 0:3d9c67d97d6f 143 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 144 blkCnt--;
emh203 0:3d9c67d97d6f 145 }
emh203 0:3d9c67d97d6f 146
emh203 0:3d9c67d97d6f 147 /* Compute Mean of squares of the input samples
emh203 0:3d9c67d97d6f 148 * and then store the result in a temporary variable, meanOfSquares. */
emh203 0:3d9c67d97d6f 149 meanOfSquares = sumOfSquares / ((float32_t) blockSize - 1.0f);
emh203 0:3d9c67d97d6f 150
emh203 0:3d9c67d97d6f 151 /* Compute mean of all input values */
emh203 0:3d9c67d97d6f 152 mean = sum / (float32_t) blockSize;
emh203 0:3d9c67d97d6f 153
emh203 0:3d9c67d97d6f 154 /* Compute square of mean */
emh203 0:3d9c67d97d6f 155 squareOfMean = (mean * mean) * (((float32_t) blockSize) /
emh203 0:3d9c67d97d6f 156 ((float32_t) blockSize - 1.0f));
emh203 0:3d9c67d97d6f 157
emh203 0:3d9c67d97d6f 158 /* Compute variance and then store the result to the destination */
emh203 0:3d9c67d97d6f 159 *pResult = meanOfSquares - squareOfMean;
emh203 0:3d9c67d97d6f 160
emh203 0:3d9c67d97d6f 161 #else
emh203 0:3d9c67d97d6f 162
emh203 0:3d9c67d97d6f 163 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 164 float32_t squareOfSum; /* Square of Sum */
emh203 0:3d9c67d97d6f 165
emh203 0:3d9c67d97d6f 166 if(blockSize == 1)
emh203 0:3d9c67d97d6f 167 {
emh203 0:3d9c67d97d6f 168 *pResult = 0;
emh203 0:3d9c67d97d6f 169 return;
emh203 0:3d9c67d97d6f 170 }
emh203 0:3d9c67d97d6f 171
emh203 0:3d9c67d97d6f 172 /* Loop over blockSize number of values */
emh203 0:3d9c67d97d6f 173 blkCnt = blockSize;
emh203 0:3d9c67d97d6f 174
emh203 0:3d9c67d97d6f 175 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 176 {
emh203 0:3d9c67d97d6f 177 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 178 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 179 * and then store the result in a temporary variable, sumOfSquares. */
emh203 0:3d9c67d97d6f 180 in = *pSrc++;
emh203 0:3d9c67d97d6f 181 sumOfSquares += in * in;
emh203 0:3d9c67d97d6f 182
emh203 0:3d9c67d97d6f 183 /* C = (A[0] + A[1] + ... + A[blockSize-1]) */
emh203 0:3d9c67d97d6f 184 /* Compute Sum of the input samples
emh203 0:3d9c67d97d6f 185 * and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 186 sum += in;
emh203 0:3d9c67d97d6f 187
emh203 0:3d9c67d97d6f 188 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 189 blkCnt--;
emh203 0:3d9c67d97d6f 190 }
emh203 0:3d9c67d97d6f 191
emh203 0:3d9c67d97d6f 192 /* Compute the square of sum */
emh203 0:3d9c67d97d6f 193 squareOfSum = ((sum * sum) / (float32_t) blockSize);
emh203 0:3d9c67d97d6f 194
emh203 0:3d9c67d97d6f 195 /* Compute the variance */
emh203 0:3d9c67d97d6f 196 *pResult = ((sumOfSquares - squareOfSum) / (float32_t) (blockSize - 1.0f));
emh203 0:3d9c67d97d6f 197
emh203 0:3d9c67d97d6f 198 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 199
emh203 0:3d9c67d97d6f 200 }
emh203 0:3d9c67d97d6f 201
emh203 0:3d9c67d97d6f 202 /**
emh203 0:3d9c67d97d6f 203 * @} end of variance group
emh203 0:3d9c67d97d6f 204 */