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			248 lines
		
	
	
		
			5.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			248 lines
		
	
	
		
			5.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| 
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| /* ----------------------------------------------------------------------
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|  * Project:      CMSIS DSP Library
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|  * Title:        arm_jensenshannon_distance_f32.c
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|  * Description:  Jensen-Shannon distance between two vectors
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|  *
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|  * $Date:        23 April 2021
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|  * $Revision:    V1.9.0
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|  *
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|  * Target Processor: Cortex-M and Cortex-A cores
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|  * -------------------------------------------------------------------- */
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| /*
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|  * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
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|  *
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|  * SPDX-License-Identifier: Apache-2.0
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|  *
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|  * Licensed under the Apache License, Version 2.0 (the License); you may
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|  * not use this file except in compliance with the License.
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|  * You may obtain a copy of the License at
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|  *
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|  * www.apache.org/licenses/LICENSE-2.0
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|  *
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|  * Unless required by applicable law or agreed to in writing, software
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|  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
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|  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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|  * See the License for the specific language governing permissions and
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|  * limitations under the License.
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|  */
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| 
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| #include "dsp/distance_functions.h"
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| #include <limits.h>
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| #include <math.h>
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| 
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| 
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| /**
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|   @addtogroup JensenShannon
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|   @{
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|  */
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| 
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| #if !defined(ARM_MATH_MVEF) || defined(ARM_MATH_AUTOVECTORIZE)
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| /// @private
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| __STATIC_INLINE float32_t rel_entr(float32_t x, float32_t y)
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| {
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|     return (x * logf(x / y));
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| }
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| #endif
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| 
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| 
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| #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
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| 
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| #include "arm_helium_utils.h"
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| #include "arm_vec_math.h"
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| 
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| float32_t arm_jensenshannon_distance_f32(const float32_t *pA,const float32_t *pB, uint32_t blockSize)
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| {
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|     uint32_t        blkCnt;
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|     float32_t       tmp;
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|     f32x4_t         a, b, t, tmpV, accumV;
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| 
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|     accumV = vdupq_n_f32(0.0f);
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| 
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|     blkCnt = blockSize >> 2;
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|     while (blkCnt > 0U) {
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|         a = vld1q(pA);
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|         b = vld1q(pB);
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| 
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|         t = vaddq(a, b);
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|         t = vmulq(t, 0.5f);
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| 
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|         tmpV = vmulq(a, vrecip_medprec_f32(t));
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|         tmpV = vlogq_f32(tmpV);
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|         accumV = vfmaq(accumV, a, tmpV);
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| 
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|         tmpV = vmulq_f32(b, vrecip_medprec_f32(t));
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|         tmpV = vlogq_f32(tmpV);
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|         accumV = vfmaq(accumV, b, tmpV);
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| 
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|         pA += 4;
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|         pB += 4;
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|         blkCnt--;
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|     }
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| 
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|     /*
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|      * tail
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|      * (will be merged thru tail predication)
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|      */
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|     blkCnt = blockSize & 3;
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|     if (blkCnt > 0U) {
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|         mve_pred16_t    p0 = vctp32q(blkCnt);
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| 
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|         a = vldrwq_z_f32(pA, p0);
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|         b = vldrwq_z_f32(pB, p0);
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| 
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|         t = vaddq(a, b);
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|         t = vmulq(t, 0.5f);
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| 
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|         tmpV = vmulq_f32(a, vrecip_medprec_f32(t));
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|         tmpV = vlogq_f32(tmpV);
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|         accumV = vfmaq_m_f32(accumV, a, tmpV, p0);
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| 
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|         tmpV = vmulq_f32(b, vrecip_medprec_f32(t));
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|         tmpV = vlogq_f32(tmpV);
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|         accumV = vfmaq_m_f32(accumV, b, tmpV, p0);
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| 
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|     }
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| 
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|     arm_sqrt_f32(vecAddAcrossF32Mve(accumV) / 2.0f, &tmp);
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|     return (tmp);
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| }
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| 
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| #else
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| 
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| #if defined(ARM_MATH_NEON)
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| 
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| #include "NEMath.h"
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| 
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| 
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| /**
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|  * @brief        Jensen-Shannon distance between two vectors
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|  *
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|  * This function is assuming that elements of second vector are > 0
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|  * and 0 only when the corresponding element of first vector is 0.
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|  * Otherwise the result of the computation does not make sense
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|  * and for speed reasons, the cases returning NaN or Infinity are not
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|  * managed.
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|  *
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|  * When the function is computing x log (x / y) with x == 0 and y == 0,
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|  * it will compute the right result (0) but a division by zero will occur
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|  * and should be ignored in client code.
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|  *
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|  * @param[in]    pA         First vector
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|  * @param[in]    pB         Second vector
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|  * @param[in]    blockSize  vector length
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|  * @return distance
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|  *
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|  */
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| 
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| 
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| float32_t arm_jensenshannon_distance_f32(const float32_t *pA,const float32_t *pB, uint32_t blockSize)
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| {
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|     float32_t accum, result, tmp,a,b;
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|     uint32_t blkCnt;
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|     float32x4_t aV,bV,t, tmpV, accumV;
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|     float32x2_t accumV2;
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| 
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|     accum = 0.0f; 
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|     accumV = vdupq_n_f32(0.0f);
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| 
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|     blkCnt = blockSize >> 2;
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|     while(blkCnt > 0)
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|     {
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|       aV = vld1q_f32(pA);
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|       bV = vld1q_f32(pB);
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|       t = vaddq_f32(aV,bV);
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|       t = vmulq_n_f32(t, 0.5f);
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| 
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|       tmpV = vmulq_f32(aV, vinvq_f32(t));
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|       tmpV = vlogq_f32(tmpV);
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|       accumV = vmlaq_f32(accumV, aV, tmpV);
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| 
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| 
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|       tmpV = vmulq_f32(bV, vinvq_f32(t));
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|       tmpV = vlogq_f32(tmpV);
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|       accumV = vmlaq_f32(accumV, bV, tmpV);
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| 
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|       pA += 4;
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|       pB += 4;
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| 
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| 
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|       blkCnt --;
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|     }
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| 
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|     accumV2 = vpadd_f32(vget_low_f32(accumV),vget_high_f32(accumV));
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|     accum = vget_lane_f32(accumV2, 0) + vget_lane_f32(accumV2, 1);
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| 
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|     blkCnt = blockSize & 3;
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|     while(blkCnt > 0)
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|     {
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|       a = *pA;
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|       b = *pB;
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|       tmp = (a + b) / 2.0f;
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|       accum += rel_entr(a, tmp);
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|       accum += rel_entr(b, tmp);
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| 
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|       pA++;
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|       pB++;
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| 
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|       blkCnt --;
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|     }
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| 
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| 
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|     arm_sqrt_f32(accum/2.0f, &result);
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|     return(result);
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| 
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| }
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| 
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| #else
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| 
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| 
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| /**
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|  * @brief        Jensen-Shannon distance between two vectors
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|  *
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|  * This function is assuming that elements of second vector are > 0
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|  * and 0 only when the corresponding element of first vector is 0.
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|  * Otherwise the result of the computation does not make sense
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|  * and for speed reasons, the cases returning NaN or Infinity are not
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|  * managed.
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|  *
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|  * When the function is computing x log (x / y) with x == 0 and y == 0,
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|  * it will compute the right result (0) but a division by zero will occur
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|  * and should be ignored in client code.
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|  *
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|  * @param[in]    pA         First vector
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|  * @param[in]    pB         Second vector
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|  * @param[in]    blockSize  vector length
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|  * @return distance
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|  *
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|  */
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| 
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| 
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| float32_t arm_jensenshannon_distance_f32(const float32_t *pA,const float32_t *pB, uint32_t blockSize)
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| {
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|     float32_t left, right,sum, result, tmp;
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|     uint32_t i;
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| 
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|     left = 0.0f; 
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|     right = 0.0f;
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|     for(i=0; i < blockSize; i++)
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|     {
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|       tmp = (pA[i] + pB[i]) / 2.0f;
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|       left  += rel_entr(pA[i], tmp);
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|       right += rel_entr(pB[i], tmp);
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|     }
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| 
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| 
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|     sum = left + right;
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|     arm_sqrt_f32(sum/2.0f, &result);
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|     return(result);
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| 
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| }
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| 
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| #endif
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| #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
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| 
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| /**
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|  * @} end of JensenShannon group
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|  */
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