1
2 /* ----------------------------------------------------------------------
3 * Project: CMSIS DSP Library
4 * Title: arm_chebyshev_distance_f64.c
5 * Description: Chebyshev distance between two vectors
6 *
7 * $Date: 10 August 2022
8 * $Revision: V1.10.1
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 @addtogroup Chebyshev
37 @{
38 */
39
40
41 /**
42 * @brief Chebyshev distance between two vectors
43 * @param[in] pA First vector
44 * @param[in] pB Second vector
45 * @param[in] blockSize vector length
46 * @return distance
47 *
48 */
arm_chebyshev_distance_f64(const float64_t * pA,const float64_t * pB,uint32_t blockSize)49 ARM_DSP_ATTRIBUTE float64_t arm_chebyshev_distance_f64(const float64_t *pA,const float64_t *pB, uint32_t blockSize)
50 {
51
52 float64_t diff=0., maxVal,tmpA, tmpB;
53 uint32_t blkCnt;
54 maxVal = F64_MIN;
55 #if defined(ARM_MATH_NEON) && defined(__aarch64__)
56 float64x2_t diffV , tmpAV , tmpBV , maxValV ;
57 maxValV = vdupq_n_f64(maxVal);
58 blkCnt = blockSize >> 1U ;
59 while(blkCnt > 0U)
60 {
61 tmpAV = vld1q_f64(pA);
62 tmpBV = vld1q_f64(pB);
63 diffV = vabsq_f64((vsubq_f64(tmpAV, tmpBV)));
64 maxValV = vmaxq_f64(maxValV, diffV);
65 pA+=2;
66 pB+=2;
67 blkCnt--;
68 }
69 maxVal =vgetq_lane_f64(maxValV, 0);
70 if(maxVal < vgetq_lane_f64(maxValV, 1))
71 {
72 maxVal = vgetq_lane_f64(maxValV, 1);
73 }
74 blkCnt = blockSize & 1;
75
76
77 #else
78 blkCnt = blockSize;
79 #endif
80
81 while(blkCnt > 0)
82 {
83 tmpA = *pA++;
84 tmpB = *pB++;
85 diff = fabs(tmpA - tmpB);
86 if (diff > maxVal)
87 {
88 maxVal = diff;
89 }
90 blkCnt --;
91 }
92
93 return(maxVal);
94 }
95
96 /**
97 * @} end of Chebyshev group
98 */
99
