Mercurial > pub > halpp

comparison f103c8/Drivers/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_std_f32.c @ 2:0c59e7a7782a

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Working on GPIO and RCC
author cin
date Mon, 16 Jan 2017 11:04:47 +0300
parents
children
comparison
equal deleted inserted replaced
1:a0b14b11ad9f 2:0c59e7a7782a
1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
3 *
4 * $Date: 19. March 2015
5 * $Revision: V.1.4.5
6 *
7 * Project: CMSIS DSP Library
8 * Title: arm_std_f32.c
9 *
10 * Description: Standard deviation of the elements of a floating-point vector.
11 *
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * - Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in
21 * the documentation and/or other materials provided with the
22 * distribution.
23 * - Neither the name of ARM LIMITED nor the names of its contributors
24 * may be used to endorse or promote products derived from this
25 * software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 * ---------------------------------------------------------------------------- */
40
41 #include "arm_math.h"
42
43 /**
44 * @ingroup groupStats
45 */
46
47 /**
48 * @defgroup STD Standard deviation
49 *
50 * Calculates the standard deviation of the elements in the input vector.
51 * The underlying algorithm is used:
52 *
53 * <pre>
54 * Result = sqrt((sumOfSquares - sum<sup>2</sup> / blockSize) / (blockSize - 1))
55 *
56 * where, sumOfSquares = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]
57 *
58 * sum = pSrc[0] + pSrc[1] + pSrc[2] + ... + pSrc[blockSize-1]
59 * </pre>
60 *
61 * There are separate functions for floating point, Q31, and Q15 data types.
62 */
63
64 /**
65 * @addtogroup STD
66 * @{
67 */
68
69
70 /**
71 * @brief Standard deviation of the elements of a floating-point vector.
72 * @param[in] *pSrc points to the input vector
73 * @param[in] blockSize length of the input vector
74 * @param[out] *pResult standard deviation value returned here
75 * @return none.
76 *
77 */
78
79
80 void arm_std_f32(
81 float32_t * pSrc,
82 uint32_t blockSize,
83 float32_t * pResult)
84 {
85 float32_t sum = 0.0f; /* Temporary result storage */
86 float32_t sumOfSquares = 0.0f; /* Sum of squares */
87 float32_t in; /* input value */
88 uint32_t blkCnt; /* loop counter */
89
90 #ifndef ARM_MATH_CM0_FAMILY
91
92 /* Run the below code for Cortex-M4 and Cortex-M3 */
93
94 float32_t meanOfSquares, mean, squareOfMean;
95
96 if(blockSize == 1)
97 {
98 *pResult = 0;
99 return;
100 }
101
102 /*loop Unrolling */
103 blkCnt = blockSize >> 2u;
104
105 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
106 ** a second loop below computes the remaining 1 to 3 samples. */
107 while(blkCnt > 0u)
108 {
109 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
110 /* Compute Sum of squares of the input samples
111 * and then store the result in a temporary variable, sum. */
112 in = *pSrc++;
113 sum += in;
114 sumOfSquares += in * in;
115 in = *pSrc++;
116 sum += in;
117 sumOfSquares += in * in;
118 in = *pSrc++;
119 sum += in;
120 sumOfSquares += in * in;
121 in = *pSrc++;
122 sum += in;
123 sumOfSquares += in * in;
124
125 /* Decrement the loop counter */
126 blkCnt--;
127 }
128
129 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
130 ** No loop unrolling is used. */
131 blkCnt = blockSize % 0x4u;
132
133 while(blkCnt > 0u)
134 {
135 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
136 /* Compute Sum of squares of the input samples
137 * and then store the result in a temporary variable, sum. */
138 in = *pSrc++;
139 sum += in;
140 sumOfSquares += in * in;
141
142 /* Decrement the loop counter */
143 blkCnt--;
144 }
145
146 /* Compute Mean of squares of the input samples
147 * and then store the result in a temporary variable, meanOfSquares. */
148 meanOfSquares = sumOfSquares / ((float32_t) blockSize - 1.0f);
149
150 /* Compute mean of all input values */
151 mean = sum / (float32_t) blockSize;
152
153 /* Compute square of mean */
154 squareOfMean = (mean * mean) * (((float32_t) blockSize) /
155 ((float32_t) blockSize - 1.0f));
156
157 /* Compute standard deviation and then store the result to the destination */
158 arm_sqrt_f32((meanOfSquares - squareOfMean), pResult);
159
160 #else
161
162 /* Run the below code for Cortex-M0 */
163
164 float32_t squareOfSum; /* Square of Sum */
165 float32_t var; /* Temporary varaince storage */
166
167 if(blockSize == 1)
168 {
169 *pResult = 0;
170 return;
171 }
172
173 /* Loop over blockSize number of values */
174 blkCnt = blockSize;
175
176 while(blkCnt > 0u)
177 {
178 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
179 /* Compute Sum of squares of the input samples
180 * and then store the result in a temporary variable, sumOfSquares. */
181 in = *pSrc++;
182 sumOfSquares += in * in;
183
184 /* C = (A[0] + A[1] + ... + A[blockSize-1]) */
185 /* Compute Sum of the input samples
186 * and then store the result in a temporary variable, sum. */
187 sum += in;
188
189 /* Decrement the loop counter */
190 blkCnt--;
191 }
192
193 /* Compute the square of sum */
194 squareOfSum = ((sum * sum) / (float32_t) blockSize);
195
196 /* Compute the variance */
197 var = ((sumOfSquares - squareOfSum) / (float32_t) (blockSize - 1.0f));
198
199 /* Compute standard deviation and then store the result to the destination */
200 arm_sqrt_f32(var, pResult);
201
202 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
203
204 }
205
206 /**
207 * @} end of STD group
208 */