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CMSIS-DSP/Source/DistanceFunctions/arm_dtw_distance_f32.c

155 lines
4.1 KiB
C

/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_braycurtis_distance_f32.c
* Description: Bray-Curtis distance between two vectors
*
* $Date: 23 April 2021
* $Revision: V1.9.0
*
* Target Processor: Cortex-M and Cortex-A cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "dsp/distance_functions.h"
#include "dsp/matrix_utils.h"
#include <limits.h>
#include <math.h>
#define E(MAT,R,C) \
(*((MAT)->pData + (MAT)->numCols*(R) + (C)))
#define WIN(R,C) \
((pWindow == NULL) ? 1 : \
((*((pWindow)->pData + (pWindow)->numCols*(R) + (C)))==1))
/**
@ingroup FloatDist
*/
/**
@defgroup DTW Dynamic Time Warping Distance
Dynamic Time Warping Distance.
This is not really a distance since triangular inequality is
not respected.
The step pattern used is symmetric2.
Future versions of this function will provide more customization options.
*/
/**
@addtogroup DTW
@{
*/
/**
* @brief Dynamic Time Warping distance
* @param[in] pDistance Distance matrix (Query rows * Template columns)
* @param[in] pWindow Windowing matrix (can be NULL if no windowing used)
* @param[out] pDTW Temporary cost buffer (same size)
* @param[out] distance Distance
* @return ARM_MATH_ARGUMENT_ERROR in case no path can be found with window constraint
*
* @par Windowing matrix
*
* The windowing matrix is used to impose some
* constraints on the search for a path.
* The algorithm will run faster (smaller search
* path) but may not be able to find a solution.
*
* The distance matrix must be initialized only
* where the windowing matrix is containing 1.
* Thus, use of a window also decreases the number
* of distances which must be computed.
*/
arm_status arm_dtw_distance_f32(const arm_matrix_instance_f32 *pDistance,
const arm_matrix_instance_q7 *pWindow,
arm_matrix_instance_f32 *pDTW,
float32_t *distance)
{
const uint32_t queryLength = pDistance -> numRows;
const uint32_t templateLength = pDistance -> numCols;
float32_t result;
float32_t *temp = pDTW->pData;
for(uint32_t q=0 ; q < queryLength; q++)
{
for(uint32_t t= 0; t < templateLength; t++)
{
*temp++ = F32_MAX;
}
}
pDTW->pData[0] = E(pDistance,0,0);
for(uint32_t q = 1; q < queryLength; q++)
{
if (!WIN(q,0))
{
continue;
}
E(pDTW,q,0) = E(pDTW,q-1,0) + E(pDistance,q,0);
}
for(uint32_t t = 1; t < templateLength; t++)
{
if (!WIN(0,t))
{
continue;
}
E(pDTW,0,t) = E(pDTW,0,t-1) + E(pDistance,0,t);
}
for(uint32_t q = 1; q < queryLength; q++)
{
for(uint32_t t = 1; t < templateLength; t++)
{
if (!WIN(q,t))
{
continue;
}
E(pDTW,q,t) =
MIN(E(pDTW,q-1,t-1) + 2.0f * E(pDistance,q,t),
MIN(E(pDTW,q,t-1) + E(pDistance,q,t),
E(pDTW,q-1,t) + E(pDistance,q,t)));
}
}
if (E(pDTW,queryLength-1,templateLength-1) == F32_MAX)
{
return(ARM_MATH_ARGUMENT_ERROR);
}
result = E(pDTW,queryLength-1,templateLength-1);
result = result / (queryLength + templateLength);
*distance = result;
return(ARM_MATH_SUCCESS);
}
/**
* @} end of DTW group
*/