| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2012 ARM Limited. All rights reserved. |
| * |
| * $Date: 17. January 2013 |
| * $Revision: V1.4.0 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_variance_example_f32.c |
| * |
| * Description: Example code demonstrating variance calculation of input sequence. |
| * |
| * Target Processor: Cortex-M4/Cortex-M3 |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * - Neither the name of ARM LIMITED nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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| * POSSIBILITY OF SUCH DAMAGE. |
| * -------------------------------------------------------------------- */ |
| |
| /** |
| * @ingroup groupExamples |
| */ |
| |
| /** |
| * @defgroup VarianceExample Variance Example |
| * |
| * \par Description: |
| * \par |
| * Demonstrates the use of Basic Math and Support Functions to calculate the variance of an |
| * input sequence with N samples. Uniformly distributed white noise is taken as input. |
| * |
| * \par Algorithm: |
| * \par |
| * The variance of a sequence is the mean of the squared deviation of the sequence from its mean. |
| * \par |
| * This is denoted by the following equation: |
| * <pre> variance = ((x[0] - x') * (x[0] - x') + (x[1] - x') * (x[1] - x') + ... + * (x[n-1] - x') * (x[n-1] - x')) / (N-1)</pre> |
| * where, <code>x[n]</code> is the input sequence, <code>N</code> is the number of input samples, and |
| * <code>x'</code> is the mean value of the input sequence, <code>x[n]</code>. |
| * \par |
| * The mean value <code>x'</code> is defined as: |
| * <pre> x' = (x[0] + x[1] + ... + x[n-1]) / N</pre> |
| * |
| * \par Block Diagram: |
| * \par |
| * \image html Variance.gif |
| * |
| * |
| * \par Variables Description: |
| * \par |
| * \li \c testInput_f32 points to the input data |
| * \li \c wire1, \c wir2, \c wire3 temporary buffers |
| * \li \c blockSize number of samples processed at a time |
| * \li \c refVarianceOut reference variance value |
| * |
| * \par CMSIS DSP Software Library Functions Used: |
| * \par |
| * - arm_dot_prod_f32() |
| * - arm_mult_f32() |
| * - arm_sub_f32() |
| * - arm_fill_f32() |
| * - arm_copy_f32() |
| * |
| * <b> Refer </b> |
| * \link arm_variance_example_f32.c \endlink |
| * |
| */ |
| |
| |
| /** \example arm_variance_example_f32.c |
| */ |
| |
| #include <math.h> |
| #include "arm_math.h" |
| |
| /* ---------------------------------------------------------------------- |
| * Defines each of the tests performed |
| * ------------------------------------------------------------------- */ |
| #define MAX_BLOCKSIZE 32 |
| #define DELTA (0.000001f) |
| |
| |
| /* ---------------------------------------------------------------------- |
| * Declare I/O buffers |
| * ------------------------------------------------------------------- */ |
| float32_t wire1[MAX_BLOCKSIZE]; |
| float32_t wire2[MAX_BLOCKSIZE]; |
| float32_t wire3[MAX_BLOCKSIZE]; |
| |
| /* ---------------------------------------------------------------------- |
| * Test input data for Floating point Variance example for 32-blockSize |
| * Generated by the MATLAB randn() function |
| * ------------------------------------------------------------------- */ |
| |
| float32_t testInput_f32[32] = |
| { |
| -0.432564811528221, -1.665584378238097, 0.125332306474831, 0.287676420358549, |
| -1.146471350681464, 1.190915465642999, 1.189164201652103, -0.037633276593318, |
| 0.327292361408654, 0.174639142820925, -0.186708577681439, 0.725790548293303, |
| -0.588316543014189, 2.183185818197101, -0.136395883086596, 0.113931313520810, |
| 1.066768211359189, 0.059281460523605, -0.095648405483669, -0.832349463650022, |
| 0.294410816392640, -1.336181857937804, 0.714324551818952, 1.623562064446271, |
| -0.691775701702287, 0.857996672828263, 1.254001421602532, -1.593729576447477, |
| -1.440964431901020, 0.571147623658178, -0.399885577715363, 0.689997375464345 |
| |
| }; |
| |
| /* ---------------------------------------------------------------------- |
| * Declare Global variables |
| * ------------------------------------------------------------------- */ |
| uint32_t blockSize = 32; |
| float32_t refVarianceOut = 0.903941793931839; |
| |
| /* ---------------------------------------------------------------------- |
| * Variance calculation test |
| * ------------------------------------------------------------------- */ |
| |
| int32_t main(void) |
| { |
| arm_status status; |
| float32_t mean, oneByBlockSize; |
| float32_t variance; |
| float32_t diff; |
| |
| status = ARM_MATH_SUCCESS; |
| |
| #if defined(FILEIO) |
| printf("START\n"); |
| #endif |
| |
| |
| /* Calculation of mean value of input */ |
| |
| /* x' = 1/blockSize * (x(0)* 1 + x(1) * 1 + ... + x(n-1) * 1) */ |
| |
| /* Fill wire1 buffer with 1.0 value */ |
| arm_fill_f32(1.0, wire1, blockSize); |
| |
| /* Calculate the dot product of wire1 and wire2 */ |
| /* (x(0)* 1 + x(1) * 1 + ...+ x(n-1) * 1) */ |
| arm_dot_prod_f32(testInput_f32, wire1, blockSize, &mean); |
| |
| /* Calculation of 1/blockSize */ |
| oneByBlockSize = 1.0 / (blockSize); |
| |
| /* 1/blockSize * (x(0)* 1 + x(1) * 1 + ... + x(n-1) * 1) */ |
| arm_mult_f32(&mean, &oneByBlockSize, &mean, 1); |
| |
| |
| /* Calculation of variance value of input */ |
| |
| /* (1/blockSize) * (x(0) - x') * (x(0) - x') + (x(1) - x') * (x(1) - x') + ... + (x(n-1) - x') * (x(n-1) - x') */ |
| |
| /* Fill wire2 with mean value x' */ |
| arm_fill_f32(mean, wire2, blockSize); |
| |
| /* wire3 contains (x-x') */ |
| arm_sub_f32(testInput_f32, wire2, wire3, blockSize); |
| |
| /* wire2 contains (x-x') */ |
| arm_copy_f32(wire3, wire2, blockSize); |
| |
| /* (x(0) - x') * (x(0) - x') + (x(1) - x') * (x(1) - x') + ... + (x(n-1) - x') * (x(n-1) - x') */ |
| arm_dot_prod_f32(wire2, wire3, blockSize, &variance); |
| |
| /* Calculation of 1/blockSize */ |
| oneByBlockSize = 1.0 / (blockSize - 1); |
| |
| /* Calculation of variance */ |
| arm_mult_f32(&variance, &oneByBlockSize, &variance, 1); |
| |
| /* absolute value of difference between ref and test */ |
| diff = fabsf(refVarianceOut - variance); |
| |
| /* Comparison of variance value with reference */ |
| |
| if (diff > DELTA) |
| { |
| status = ARM_MATH_TEST_FAILURE; |
| } |
| |
| |
| #if !defined(FILEIO) |
| if ( status != ARM_MATH_SUCCESS) |
| { |
| while (1); |
| } |
| |
| while (1); /* main function does not return */ |
| #else |
| if (status == ARM_MATH_SUCCESS) |
| { |
| printf("SUCCESS\n"); |
| } |
| else |
| { |
| printf("FAILURE\n"); |
| } |
| #endif |
| } |
| |
| /** \endlink */ |
| |
| |