1  
 2  /* ----------------------------------------------------------------------
 3   * Project:      CMSIS DSP Library
 4   * Title:        arm_hamming_distance.c
 5   * Description:  Hamming 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  extern void arm_boolean_distance_TF_FT(const uint32_t *pA
36         , const uint32_t *pB
37         , uint32_t numberOfBools
38         , uint32_t *cTF
39         , uint32_t *cFT
40         );
41  
42  /**
43    @addtogroup BoolDist
44    @{
45   */
46  
47  
48  /**
49   * @brief        Hamming distance between two vectors
50   *
51   * @param[in]    pA              First vector of packed booleans
52   * @param[in]    pB              Second vector of packed booleans
53   * @param[in]    numberOfBools   Number of booleans
54   * @return distance
55   *
56   */
57  
58  float32_t arm_hamming_distance(const uint32_t *pA, const uint32_t *pB, uint32_t numberOfBools)
59  {
60      uint32_t ctf=0,cft=0;
61  
62      arm_boolean_distance_TF_FT(pA, pB, numberOfBools, &ctf, &cft);
63  
64      return(1.0*(ctf + cft) / numberOfBools);
65  }
66  
67  
68  /**
69   * @} end of BoolDist group
70   */