1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_logsumexp_f32.c
4 * Description: LogSumExp
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 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 "dsp/statistics_functions.h"
30 #include <limits.h>
31 #include <math.h>
32
33
34 /**
35 * @addtogroup Entropy
36 * @{
37 */
38
39
40 /**
41 * @brief Entropy
42 *
43 * @param[in] pSrcA Array of input values.
44 * @param[in] blockSize Number of samples in the input array.
45 * @return Entropy -Sum(p ln p)
46 *
47 */
48
49 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
50
51 #include "arm_helium_utils.h"
52 #include "arm_vec_math.h"
53
arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)54 float32_t arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)
55 {
56 uint32_t blkCnt;
57 float32_t accum=0.0f,p;
58
59
60 blkCnt = blockSize;
61
62 f32x4_t vSum = vdupq_n_f32(0.0f);
63 /* Compute 4 outputs at a time */
64 blkCnt = blockSize >> 2U;
65
66 while (blkCnt > 0U)
67 {
68 f32x4_t vecIn = vld1q(pSrcA);
69
70 vSum = vaddq_f32(vSum, vmulq(vecIn, vlogq_f32(vecIn)));
71
72 /*
73 * Decrement the blockSize loop counter
74 * Advance vector source and destination pointers
75 */
76 pSrcA += 4;
77 blkCnt --;
78 }
79
80 accum = vecAddAcrossF32Mve(vSum);
81
82 /* Tail */
83 blkCnt = blockSize & 0x3;
84 while(blkCnt > 0)
85 {
86 p = *pSrcA++;
87 accum += p * logf(p);
88
89 blkCnt--;
90
91 }
92
93 return (-accum);
94 }
95
96 #else
97 #if defined(ARM_MATH_NEON) && !defined(ARM_MATH_AUTOVECTORIZE)
98
99 #include "NEMath.h"
100
arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)101 float32_t arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)
102 {
103 const float32_t *pIn;
104 uint32_t blkCnt;
105 float32_t accum, p;
106
107 float32x4_t accumV;
108 float32x2_t accumV2;
109 float32x4_t tmpV, tmpV2;
110
111 pIn = pSrcA;
112
113 accum = 0.0f;
114 accumV = vdupq_n_f32(0.0f);
115
116 blkCnt = blockSize >> 2;
117 while(blkCnt > 0)
118 {
119 tmpV = vld1q_f32(pIn);
120 pIn += 4;
121
122 tmpV2 = vlogq_f32(tmpV);
123 accumV = vmlaq_f32(accumV, tmpV, tmpV2);
124
125 blkCnt--;
126
127 }
128
129 accumV2 = vpadd_f32(vget_low_f32(accumV),vget_high_f32(accumV));
130 accum = vget_lane_f32(accumV2, 0) + vget_lane_f32(accumV2, 1);
131
132
133 blkCnt = blockSize & 3;
134 while(blkCnt > 0)
135 {
136 p = *pIn++;
137 accum += p * logf(p);
138
139 blkCnt--;
140
141 }
142
143 return(-accum);
144 }
145
146 #else
arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)147 float32_t arm_entropy_f32(const float32_t * pSrcA,uint32_t blockSize)
148 {
149 const float32_t *pIn;
150 uint32_t blkCnt;
151 float32_t accum, p;
152
153 pIn = pSrcA;
154 blkCnt = blockSize;
155
156 accum = 0.0f;
157
158 while(blkCnt > 0)
159 {
160 p = *pIn++;
161 accum += p * logf(p);
162
163 blkCnt--;
164
165 }
166
167 return(-accum);
168 }
169 #endif
170 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
171
172 /**
173 * @} end of Entropy group
174 */
175