init

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) */ 
+