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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_f32.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_f32.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_f32.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_f32.c new file mode 100644 index 0000000..214a794 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_f32.c @@ -0,0 +1,188 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_std_f32.c
+ * Description: Standard deviation of the elements of a floating-point vector
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 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 "arm_math.h"
+
+/**
+ @ingroup groupStats
+ */
+
+/**
+ @defgroup STD Standard deviation
+
+ Calculates the standard deviation of the elements in the input vector.
+ The underlying algorithm is used:
+
+ <pre>
+ Result = sqrt((sumOfSquares - sum<sup>2</sup> / blockSize) / (blockSize - 1))
+
+ sumOfSquares = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]
+ sum = pSrc[0] + pSrc[1] + pSrc[2] + ... + pSrc[blockSize-1]
+ </pre>
+
+ There are separate functions for floating point, Q31, and Q15 data types.
+ */
+
+/**
+ @addtogroup STD
+ @{
+ */
+
+/**
+ @brief Standard deviation of the elements of a floating-point vector.
+ @param[in] pSrc points to the input vector
+ @param[in] blockSize number of samples in input vector
+ @param[out] pResult standard deviation value returned here
+ @return none
+ */
+#if defined(ARM_MATH_NEON_EXPERIMENTAL)
+void arm_std_f32(
+ const float32_t * pSrc,
+ uint32_t blockSize,
+ float32_t * pResult)
+{
+ float32_t var;
+ arm_var_f32(pSrc,blockSize,&var);
+ arm_sqrt_f32(var, pResult);
+}
+#else
+void arm_std_f32(
+ const float32_t * pSrc,
+ uint32_t blockSize,
+ float32_t * pResult)
+{
+ uint32_t blkCnt; /* Loop counter */
+ float32_t sum = 0.0f; /* Temporary result storage */
+ float32_t sumOfSquares = 0.0f; /* Sum of squares */
+ float32_t in; /* Temporary variable to store input value */
+
+#ifndef ARM_MATH_CM0_FAMILY
+ float32_t meanOfSquares, mean, squareOfMean; /* Temporary variables */
+#else
+ float32_t squareOfSum; /* Square of Sum */
+ float32_t var; /* Temporary varaince storage */
+#endif
+
+ if (blockSize <= 1U)
+ {
+ *pResult = 0;
+ return;
+ }
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time */
+ blkCnt = blockSize >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */
+ /* C = A[0] + A[1] + ... + A[blockSize-1] */
+
+ in = *pSrc++;
+ /* Compute sum of squares and store result in a temporary variable, sumOfSquares. */
+ sumOfSquares += in * in;
+ /* Compute sum and store result in a temporary variable, sum. */
+ sum += in;
+
+ in = *pSrc++;
+ sumOfSquares += in * in;
+ sum += in;
+
+ in = *pSrc++;
+ sumOfSquares += in * in;
+ sum += in;
+
+ in = *pSrc++;
+ sumOfSquares += in * in;
+ sum += in;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (blkCnt > 0U)
+ {
+ /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */
+ /* C = A[0] + A[1] + ... + A[blockSize-1] */
+
+ in = *pSrc++;
+ /* Compute sum of squares and store result in a temporary variable, sumOfSquares. */
+ sumOfSquares += ( in * in);
+ /* Compute sum and store result in a temporary variable, sum. */
+ sum += in;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+ /* Compute Mean of squares and store result in a temporary variable, meanOfSquares. */
+ meanOfSquares = sumOfSquares / ((float32_t) blockSize - 1.0f);
+
+ /* Compute mean of all input values */
+ mean = sum / (float32_t) blockSize;
+
+ /* Compute square of mean */
+ squareOfMean = (mean * mean) * (((float32_t) blockSize) /
+ ((float32_t) blockSize - 1.0f));
+
+ /* Compute standard deviation and store result to destination */
+ arm_sqrt_f32((meanOfSquares - squareOfMean), pResult);
+
+#else
+ /* Run the below code for Cortex-M0 */
+
+ /* Compute square of sum */
+ squareOfSum = ((sum * sum) / (float32_t) blockSize);
+
+ /* Compute variance */
+ var = ((sumOfSquares - squareOfSum) / (float32_t) (blockSize - 1.0f));
+
+ /* Compute standard deviation and store result in destination */
+ arm_sqrt_f32(var, pResult);
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+#endif /* #if defined(ARM_MATH_NEON) */
+
+/**
+ @} end of STD group
+ */
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