summaryrefslogtreecommitdiffstats
path: root/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c
diff options
context:
space:
mode:
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c')
-rw-r--r--Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c
new file mode 100644
index 0000000..6fd106a
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_f64.c
@@ -0,0 +1,100 @@
+/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_var_f64.c
+ * Description: Variance of the elements of a floating-point vector
+ *
+ * $Date: 13 September 2021
+ * $Revision: V1.10.0
+ *
+ * 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/statistics_functions.h"
+
+/**
+ @ingroup groupStats
+ */
+
+/**
+ @addtogroup variance
+ @{
+ */
+
+/**
+ @brief Variance 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 variance value returned here
+ @return none
+ */
+void arm_var_f64(
+ const float64_t * pSrc,
+ uint32_t blockSize,
+ float64_t * pResult)
+{
+ uint32_t blkCnt; /* Loop counter */
+ float64_t sum = 0.; /* Temporary result storage */
+ float64_t fSum = 0.;
+ float64_t fMean, fValue;
+ const float64_t * pInput = pSrc;
+
+ if (blockSize <= 1U)
+ {
+ *pResult = 0;
+ return;
+ }
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+ while (blkCnt > 0U)
+ {
+ /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */
+
+ sum += *pInput++;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) / blockSize */
+ fMean = sum / (float64_t) blockSize;
+
+ pInput = pSrc;
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+ while (blkCnt > 0U)
+ {
+ fValue = *pInput++ - fMean;
+ fSum += fValue * fValue;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Variance */
+ *pResult = fSum / (float64_t)(blockSize - 1.);
+}
+
+/**
+ @} end of variance group
+ */