1
2 /* ----------------------------------------------------------------------
3 * Project: CMSIS DSP Library
4 * Title: arm_correlation_distance_f32.c
5 * Description: Correlation distance between two vectors
6 *
7 * $Date: 23 April 2021
8 * $Revision: V1.9.0
9 *
10 * Target Processor: Cortex-M and Cortex-A cores
11 * -------------------------------------------------------------------- */
12 /*
13 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
14 *
15 * SPDX-License-Identifier: Apache-2.0
16 *
17 * Licensed under the Apache License, Version 2.0 (the License); you may
18 * not use this file except in compliance with the License.
19 * You may obtain a copy of the License at
20 *
21 * www.apache.org/licenses/LICENSE-2.0
22 *
23 * Unless required by applicable law or agreed to in writing, software
24 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
25 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
26 * See the License for the specific language governing permissions and
27 * limitations under the License.
28 */
29
30 #include "dsp/distance_functions.h"
31 #include <limits.h>
32 #include <math.h>
33
34
35
36 /**
37 @addtogroup Correlation
38 @{
39 */
40
41
42 /**
43 * @brief Correlation distance between two vectors
44 *
45 * The input vectors are modified in place !
46 *
47 * @param[in] pA First vector
48 * @param[in] pB Second vector
49 * @param[in] blockSize vector length
50 * @return distance
51 *
52 */
53
arm_correlation_distance_f32(float32_t * pA,float32_t * pB,uint32_t blockSize)54 float32_t arm_correlation_distance_f32(float32_t *pA,float32_t *pB, uint32_t blockSize)
55 {
56 float32_t ma,mb,pwra,pwrb,dot,tmp;
57
58 arm_mean_f32(pA, blockSize, &ma);
59 arm_mean_f32(pB, blockSize, &mb);
60
61 arm_offset_f32(pA, -ma, pA, blockSize);
62 arm_offset_f32(pB, -mb, pB, blockSize);
63
64 arm_power_f32(pA, blockSize, &pwra);
65 arm_power_f32(pB, blockSize, &pwrb);
66
67 arm_dot_prod_f32(pA,pB,blockSize,&dot);
68
69 dot = dot / blockSize;
70 pwra = pwra / blockSize;
71 pwrb = pwrb / blockSize;
72
73 arm_sqrt_f32(pwra * pwrb,&tmp);
74
75 return(1.0f - dot / tmp);
76
77
78 }
79
80
81
82 /**
83 * @} end of Correlation group
84 */
85
