1 
2 /* ----------------------------------------------------------------------
3  * Project:      CMSIS DSP Library
4  * Title:        arm_dtw_path_f32.c
5  * Description:  Warping path
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) 2010-2022 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 #include <stdlib.h>
34 
35 
36 /**
37   @addtogroup DTW
38   @{
39  */
40 
41 
42 /**
43  * @brief        Window for dynamic time warping computation
44  * @param[in]    windowType  Type of window
45  * @param[in]    windowSize  Window size
46  * @param[in,out] pWindow Window
47  * @return Error if window type not recognized
48  *
49  * @par Windowing matrix
50  * The window matrix will contain 1 for the
51  * position which are accepted and 0 for the
52  * positions which are rejected.
53  *
54  * The input matrix must already contain a buffer
55  * and the number of rows (query length) and columns
56  * (template length) must be initialized.
57  * The function will fill the matrix with 0 and 1.
58  *
59  */
arm_dtw_init_window_q7(const arm_dtw_window windowType,const int32_t windowSize,arm_matrix_instance_q7 * pWindow)60 arm_status arm_dtw_init_window_q7(const arm_dtw_window windowType,
61                             const int32_t windowSize,
62                             arm_matrix_instance_q7 *pWindow)
63 {
64   const int32_t queryLength = pWindow -> numRows;
65   const int32_t templateLength = pWindow -> numCols;
66 
67   switch(windowType)
68   {
69      case ARM_DTW_SAKOE_CHIBA_WINDOW:
70      {
71         for(int32_t q = 0; q < queryLength; q++)
72         {
73            for(int32_t t = 0; t < templateLength; t++)
74            {
75               pWindow->pData[templateLength*q + t] = (q7_t)(abs(q-t) <= windowSize);
76            }
77         }
78      }
79      break;
80 /*
81      case ARM_DTW_ITAKURA_WINDOW:
82      {
83         for(int32_t q = 0; q < queryLength; q++)
84         {
85            for(int32_t t = 0; t < templateLength; t++)
86            {
87               pWindow->pData[templateLength*q + t] = (q7_t)(
88                  (t < 2 * q) &&
89                  (q <= 2 * t) &&
90                  (q >= queryLength - 1 - 2 * (templateLength - t)) &&
91                  (t > templateLength - 1 - 2 * (queryLength - q)));
92            }
93         }
94      }
95      break;
96 */
97      case ARM_DTW_SLANTED_BAND_WINDOW:
98      {
99         for(int32_t q = 0; q < queryLength; q++)
100         {
101            for(int32_t t = 0; t < templateLength; t++)
102            {
103               float32_t diag = (1.0f * q * templateLength / queryLength);
104               pWindow->pData[templateLength*q + t] = (q7_t)(fabsf((float32_t)t - diag) <= (float32_t)windowSize);
105            }
106         }
107      }
108      break;
109 
110      default:
111       return(ARM_MATH_ARGUMENT_ERROR);
112   }
113 
114   return(ARM_MATH_SUCCESS);
115 }
116 
117 /**
118  * @} end of DTW group
119  */
120 
121