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Drivers/CMSIS/DSP/Source/DistanceFunctions/arm_canberra_distance_f16.c

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+
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_canberra_distance_f16.c
+ * Description:  Canberra 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 Canberra Canberra distance
+
+  Canberra distance
+ */
+
+
+/**
+  @addtogroup Canberra
+  @{
+ */
+
+
+/**
+ * @brief        Canberra distance between two vectors
+ *
+ * This function may divide by zero when samples pA[i] and pB[i] are both zero.
+ * The result of the computation will be correct. So the division per zero may be
+ * ignored.
+ *
+ * @param[in]    pA         First vector
+ * @param[in]    pB         Second vector
+ * @param[in]    blockSize  vector length
+ * @return distance
+ *
+ */
+
+#if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
+
+#include "arm_helium_utils.h"
+#include "arm_vec_math_f16.h"
+
+float16_t arm_canberra_distance_f16(const float16_t *pA,const float16_t *pB, uint32_t blockSize)
+{
+    _Float16       accum = 0.0f16;
+    uint32_t         blkCnt;
+    f16x8_t         a, b, c, accumV;
+
+    accumV = vdupq_n_f16(0.0f);
+
+    blkCnt = blockSize >> 3;
+    while (blkCnt > 0) {
+        a = vld1q(pA);
+        b = vld1q(pB);
+
+        c = vabdq(a, b);
+
+        a = vabsq(a);
+        b = vabsq(b);
+        a = vaddq(a, b);
+
+        /* 
+         * May divide by zero when a and b have both the same lane at zero.
+         */
+        a = vrecip_hiprec_f16(a);
+
+        /*
+         * Force result of a division by 0 to 0. It the behavior of the
+         * sklearn canberra function.
+         */
+        a = vdupq_m_n_f16(a, 0.0f, vcmpeqq(a, 0.0f));
+        c = vmulq(c, a);
+        accumV = vaddq(accumV, c);
+
+        pA += 8;
+        pB += 8;
+        blkCnt--;
+    }
+
+    blkCnt = blockSize & 7;
+    if (blkCnt > 0U) {
+        mve_pred16_t    p0 = vctp16q(blkCnt);
+
+        a = vldrhq_z_f16(pA, p0);
+        b = vldrhq_z_f16(pB, p0);
+
+        c = vabdq(a, b);
+
+        a = vabsq(a);
+        b = vabsq(b);
+        a = vaddq(a, b);
+
+        /* 
+         * May divide by zero when a and b have both the same lane at zero.
+         */
+        a = vrecip_hiprec_f16(a);
+
+        /*
+         * Force result of a division by 0 to 0. It the behavior of the
+         * sklearn canberra function.
+         */
+        a = vdupq_m_n_f16(a, 0.0f, vcmpeqq(a, 0.0f));
+        c = vmulq(c, a);
+        accumV = vaddq_m(accumV, accumV, c, p0);
+    }
+
+    accum = vecAddAcrossF16Mve(accumV);
+
+    return (accum);
+}
+
+
+#else
+float16_t arm_canberra_distance_f16(const float16_t *pA,const float16_t *pB, uint32_t blockSize)
+{
+   _Float16 accum=0.0f, tmpA, tmpB,diff,sum;
+
+   while(blockSize > 0)
+   {
+      tmpA = *pA++;
+      tmpB = *pB++;
+
+      diff = fabsf((float32_t)((_Float16)tmpA - (_Float16)tmpB));
+      sum = (_Float16)fabsf((float32_t)tmpA) + (_Float16)fabsf((float32_t)tmpB);
+      if (((_Float16)tmpA != 0.0f16) || ((_Float16)tmpB != 0.0f16))
+      {
+         accum += ((_Float16)diff / (_Float16)sum);
+      }
+      blockSize --;
+   }
+   return(accum);
+}
+#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
+
+
+/**
+ * @} end of Canberra group
+ */
+
+#endif /* #if defined(ARM_FLOAT16_SUPPORTED) */ 
+