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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_jensenshannon_distance_f16.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_jensenshannon_distance_f16.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_jensenshannon_distance_f16.c b/Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_jensenshannon_distance_f16.c new file mode 100644 index 0000000..b31ef34 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_jensenshannon_distance_f16.c @@ -0,0 +1,177 @@ + +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_jensenshannon_distance_f16.c + * Description: Jensen-Shannon 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_f16.h" + +#if defined(ARM_FLOAT16_SUPPORTED) + +#include <limits.h> +#include <math.h> + +/** + @ingroup FloatDist + */ + +/** + @defgroup JensenShannon Jensen-Shannon distance + + Jensen-Shannon distance + */ + + +/** + @addtogroup JensenShannon + @{ + */ + +#if !defined(ARM_MATH_MVE_FLOAT16) || defined(ARM_MATH_AUTOVECTORIZE) +/// @private +__STATIC_INLINE float16_t rel_entr(float16_t x, float16_t y) +{ + return ((_Float16)x * (_Float16)logf((float32_t)((_Float16)x / (_Float16)y))); +} +#endif + + +#if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE) + +#include "arm_helium_utils.h" +#include "arm_vec_math_f16.h" + +float16_t arm_jensenshannon_distance_f16(const float16_t *pA,const float16_t *pB, uint32_t blockSize) +{ + uint32_t blkCnt; + float16_t tmp; + f16x8_t a, b, t, tmpV, accumV; + + accumV = vdupq_n_f16(0.0f); + + blkCnt = blockSize >> 3; + while (blkCnt > 0U) { + a = vld1q(pA); + b = vld1q(pB); + + t = vaddq(a, b); + t = vmulq(t, 0.5f); + + tmpV = vmulq(a, vrecip_medprec_f16(t)); + tmpV = vlogq_f16(tmpV); + accumV = vfmaq(accumV, a, tmpV); + + tmpV = vmulq_f16(b, vrecip_medprec_f16(t)); + tmpV = vlogq_f16(tmpV); + accumV = vfmaq(accumV, b, tmpV); + + pA += 8; + pB += 8; + blkCnt--; + } + + /* + * tail + * (will be merged thru tail predication) + */ + blkCnt = blockSize & 7; + if (blkCnt > 0U) { + mve_pred16_t p0 = vctp16q(blkCnt); + + a = vldrhq_z_f16(pA, p0); + b = vldrhq_z_f16(pB, p0); + + t = vaddq(a, b); + t = vmulq(t, 0.5f); + + tmpV = vmulq_f16(a, vrecip_medprec_f16(t)); + tmpV = vlogq_f16(tmpV); + accumV = vfmaq_m_f16(accumV, a, tmpV, p0); + + tmpV = vmulq_f16(b, vrecip_medprec_f16(t)); + tmpV = vlogq_f16(tmpV); + accumV = vfmaq_m_f16(accumV, b, tmpV, p0); + + } + + arm_sqrt_f16((_Float16)vecAddAcrossF16Mve(accumV) / 2.0f16, &tmp); + return (tmp); +} + +#else + + +/** + * @brief Jensen-Shannon distance between two vectors + * + * This function is assuming that elements of second vector are > 0 + * and 0 only when the corresponding element of first vector is 0. + * Otherwise the result of the computation does not make sense + * and for speed reasons, the cases returning NaN or Infinity are not + * managed. + * + * When the function is computing x log (x / y) with x == 0 and y == 0, + * it will compute the right result (0) but a division by zero will occur + * and should be ignored in client code. + * + * @param[in] pA First vector + * @param[in] pB Second vector + * @param[in] blockSize vector length + * @return distance + * + */ + + +float16_t arm_jensenshannon_distance_f16(const float16_t *pA,const float16_t *pB, uint32_t blockSize) +{ + _Float16 left, right,sum, tmp; + float16_t result; + uint32_t i; + + left = 0.0f16; + right = 0.0f16; + for(i=0; i < blockSize; i++) + { + tmp = ((_Float16)pA[i] + (_Float16)pB[i]) / 2.0f16; + left += (_Float16)rel_entr(pA[i], tmp); + right += (_Float16)rel_entr(pB[i], tmp); + } + + + sum = left + right; + arm_sqrt_f16((_Float16)sum/2.0f16, &result); + return(result); + +} + +#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */ + +/** + * @} end of JensenShannon group + */ + +#endif /* #if defined(ARM_FLOAT16_SUPPORTED) */ + |