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Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_lms_f32.c')
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diff --git a/DSP_Lib/Source/FilteringFunctions/arm_lms_f32.c b/DSP_Lib/Source/FilteringFunctions/arm_lms_f32.c deleted file mode 100644 index 269330c..0000000 --- a/DSP_Lib/Source/FilteringFunctions/arm_lms_f32.c +++ /dev/null @@ -1,442 +0,0 @@ -/* ---------------------------------------------------------------------- -* Copyright (C) 2010-2014 ARM Limited. All rights reserved. -* -* $Date: 19. March 2015 -* $Revision: V.1.4.5 -* -* Project: CMSIS DSP Library -* Title: arm_lms_f32.c -* -* Description: Processing function for the floating-point LMS filter. -* -* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 -* -* 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 -* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -* POSSIBILITY OF SUCH DAMAGE. -* -------------------------------------------------------------------- */ - -#include "arm_math.h" - -/** - * @ingroup groupFilters - */ - -/** - * @defgroup LMS Least Mean Square (LMS) Filters - * - * LMS filters are a class of adaptive filters that are able to "learn" an unknown transfer functions. - * LMS filters use a gradient descent method in which the filter coefficients are updated based on the instantaneous error signal. - * Adaptive filters are often used in communication systems, equalizers, and noise removal. - * The CMSIS DSP Library contains LMS filter functions that operate on Q15, Q31, and floating-point data types. - * The library also contains normalized LMS filters in which the filter coefficient adaptation is indepedent of the level of the input signal. - * - * An LMS filter consists of two components as shown below. - * The first component is a standard transversal or FIR filter. - * The second component is a coefficient update mechanism. - * The LMS filter has two input signals. - * The "input" feeds the FIR filter while the "reference input" corresponds to the desired output of the FIR filter. - * That is, the FIR filter coefficients are updated so that the output of the FIR filter matches the reference input. - * The filter coefficient update mechanism is based on the difference between the FIR filter output and the reference input. - * This "error signal" tends towards zero as the filter adapts. - * The LMS processing functions accept the input and reference input signals and generate the filter output and error signal. - * \image html LMS.gif "Internal structure of the Least Mean Square filter" - * - * The functions operate on blocks of data and each call to the function processes - * <code>blockSize</code> samples through the filter. - * <code>pSrc</code> points to input signal, <code>pRef</code> points to reference signal, - * <code>pOut</code> points to output signal and <code>pErr</code> points to error signal. - * All arrays contain <code>blockSize</code> values. - * - * The functions operate on a block-by-block basis. - * Internally, the filter coefficients <code>b[n]</code> are updated on a sample-by-sample basis. - * The convergence of the LMS filter is slower compared to the normalized LMS algorithm. - * - * \par Algorithm: - * The output signal <code>y[n]</code> is computed by a standard FIR filter: - * <pre> - * y[n] = b[0] * x[n] + b[1] * x[n-1] + b[2] * x[n-2] + ...+ b[numTaps-1] * x[n-numTaps+1] - * </pre> - * - * \par - * The error signal equals the difference between the reference signal <code>d[n]</code> and the filter output: - * <pre> - * e[n] = d[n] - y[n]. - * </pre> - * - * \par - * After each sample of the error signal is computed, the filter coefficients <code>b[k]</code> are updated on a sample-by-sample basis: - * <pre> - * b[k] = b[k] + e[n] * mu * x[n-k], for k=0, 1, ..., numTaps-1 - * </pre> - * where <code>mu</code> is the step size and controls the rate of coefficient convergence. - *\par - * In the APIs, <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>. - * Coefficients are stored in time reversed order. - * \par - * <pre> - * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]} - * </pre> - * \par - * <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>. - * Samples in the state buffer are stored in the order: - * \par - * <pre> - * {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]} - * </pre> - * \par - * Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code> samples. - * The increased state buffer length allows circular addressing, which is traditionally used in FIR filters, - * to be avoided and yields a significant speed improvement. - * The state variables are updated after each block of data is processed. - * \par Instance Structure - * The coefficients and state variables for a filter are stored together in an instance data structure. - * A separate instance structure must be defined for each filter and - * coefficient and state arrays cannot be shared among instances. - * There are separate instance structure declarations for each of the 3 supported data types. - * - * \par Initialization Functions - * There is also an associated initialization function for each data type. - * The initialization function performs the following operations: - * - Sets the values of the internal structure fields. - * - Zeros out the values in the state buffer. - * To do this manually without calling the init function, assign the follow subfields of the instance structure: - * numTaps, pCoeffs, mu, postShift (not for f32), pState. Also set all of the values in pState to zero. - * - * \par - * Use of the initialization function is optional. - * However, if the initialization function is used, then the instance structure cannot be placed into a const data section. - * To place an instance structure into a const data section, the instance structure must be manually initialized. - * Set the values in the state buffer to zeros before static initialization. - * The code below statically initializes each of the 3 different data type filter instance structures - * <pre> - * arm_lms_instance_f32 S = {numTaps, pState, pCoeffs, mu}; - * arm_lms_instance_q31 S = {numTaps, pState, pCoeffs, mu, postShift}; - * arm_lms_instance_q15 S = {numTaps, pState, pCoeffs, mu, postShift}; - * </pre> - * where <code>numTaps</code> is the number of filter coefficients in the filter; <code>pState</code> is the address of the state buffer; - * <code>pCoeffs</code> is the address of the coefficient buffer; <code>mu</code> is the step size parameter; and <code>postShift</code> is the shift applied to coefficients. - * - * \par Fixed-Point Behavior: - * Care must be taken when using the Q15 and Q31 versions of the LMS filter. - * The following issues must be considered: - * - Scaling of coefficients - * - Overflow and saturation - * - * \par Scaling of Coefficients: - * Filter coefficients are represented as fractional values and - * coefficients are restricted to lie in the range <code>[-1 +1)</code>. - * The fixed-point functions have an additional scaling parameter <code>postShift</code>. - * At the output of the filter's accumulator is a shift register which shifts the result by <code>postShift</code> bits. - * This essentially scales the filter coefficients by <code>2^postShift</code> and - * allows the filter coefficients to exceed the range <code>[+1 -1)</code>. - * The value of <code>postShift</code> is set by the user based on the expected gain through the system being modeled. - * - * \par Overflow and Saturation: - * Overflow and saturation behavior of the fixed-point Q15 and Q31 versions are - * described separately as part of the function specific documentation below. - */ - -/** - * @addtogroup LMS - * @{ - */ - -/** - * @details - * This function operates on floating-point data types. - * - * @brief Processing function for floating-point LMS filter. - * @param[in] *S points to an instance of the floating-point LMS filter structure. - * @param[in] *pSrc points to the block of input data. - * @param[in] *pRef points to the block of reference data. - * @param[out] *pOut points to the block of output data. - * @param[out] *pErr points to the block of error data. - * @param[in] blockSize number of samples to process. - * @return none. - */ - -void arm_lms_f32( - const arm_lms_instance_f32 * S, - float32_t * pSrc, - float32_t * pRef, - float32_t * pOut, - float32_t * pErr, - uint32_t blockSize) -{ - float32_t *pState = S->pState; /* State pointer */ - float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ - float32_t *pStateCurnt; /* Points to the current sample of the state */ - float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ - float32_t mu = S->mu; /* Adaptive factor */ - uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ - uint32_t tapCnt, blkCnt; /* Loop counters */ - float32_t sum, e, d; /* accumulator, error, reference data sample */ - float32_t w = 0.0f; /* weight factor */ - - e = 0.0f; - d = 0.0f; - - /* S->pState points to state array which contains previous frame (numTaps - 1) samples */ - /* pStateCurnt points to the location where the new input data should be written */ - pStateCurnt = &(S->pState[(numTaps - 1u)]); - - blkCnt = blockSize; - - -#ifndef ARM_MATH_CM0_FAMILY - - /* Run the below code for Cortex-M4 and Cortex-M3 */ - - while(blkCnt > 0u) - { - /* Copy the new input sample into the state buffer */ - *pStateCurnt++ = *pSrc++; - - /* Initialize pState pointer */ - px = pState; - - /* Initialize coeff pointer */ - pb = (pCoeffs); - - /* Set the accumulator to zero */ - sum = 0.0f; - - /* Loop unrolling. Process 4 taps at a time. */ - tapCnt = numTaps >> 2; - - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - sum += (*px++) * (*pb++); - sum += (*px++) * (*pb++); - sum += (*px++) * (*pb++); - sum += (*px++) * (*pb++); - - /* Decrement the loop counter */ - tapCnt--; - } - - /* If the filter length is not a multiple of 4, compute the remaining filter taps */ - tapCnt = numTaps % 0x4u; - - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - sum += (*px++) * (*pb++); - - /* Decrement the loop counter */ - tapCnt--; - } - - /* The result in the accumulator, store in the destination buffer. */ - *pOut++ = sum; - - /* Compute and store error */ - d = (float32_t) (*pRef++); - e = d - sum; - *pErr++ = e; - - /* Calculation of Weighting factor for the updating filter coefficients */ - w = e * mu; - - /* Initialize pState pointer */ - px = pState; - - /* Initialize coeff pointer */ - pb = (pCoeffs); - - /* Loop unrolling. Process 4 taps at a time. */ - tapCnt = numTaps >> 2; - - /* Update filter coefficients */ - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - *pb = *pb + (w * (*px++)); - pb++; - - *pb = *pb + (w * (*px++)); - pb++; - - *pb = *pb + (w * (*px++)); - pb++; - - *pb = *pb + (w * (*px++)); - pb++; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* If the filter length is not a multiple of 4, compute the remaining filter taps */ - tapCnt = numTaps % 0x4u; - - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - *pb = *pb + (w * (*px++)); - pb++; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Advance state pointer by 1 for the next sample */ - pState = pState + 1; - - /* Decrement the loop counter */ - blkCnt--; - } - - - /* Processing is complete. Now copy the last numTaps - 1 samples to the - satrt of the state buffer. This prepares the state buffer for the - next function call. */ - - /* Points to the start of the pState buffer */ - pStateCurnt = S->pState; - - /* Loop unrolling for (numTaps - 1u) samples copy */ - tapCnt = (numTaps - 1u) >> 2u; - - /* copy data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Calculate remaining number of copies */ - tapCnt = (numTaps - 1u) % 0x4u; - - /* Copy the remaining q31_t data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - -#else - - /* Run the below code for Cortex-M0 */ - - while(blkCnt > 0u) - { - /* Copy the new input sample into the state buffer */ - *pStateCurnt++ = *pSrc++; - - /* Initialize pState pointer */ - px = pState; - - /* Initialize pCoeffs pointer */ - pb = pCoeffs; - - /* Set the accumulator to zero */ - sum = 0.0f; - - /* Loop over numTaps number of values */ - tapCnt = numTaps; - - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - sum += (*px++) * (*pb++); - - /* Decrement the loop counter */ - tapCnt--; - } - - /* The result is stored in the destination buffer. */ - *pOut++ = sum; - - /* Compute and store error */ - d = (float32_t) (*pRef++); - e = d - sum; - *pErr++ = e; - - /* Weighting factor for the LMS version */ - w = e * mu; - - /* Initialize pState pointer */ - px = pState; - - /* Initialize pCoeffs pointer */ - pb = pCoeffs; - - /* Loop over numTaps number of values */ - tapCnt = numTaps; - - while(tapCnt > 0u) - { - /* Perform the multiply-accumulate */ - *pb = *pb + (w * (*px++)); - pb++; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Advance state pointer by 1 for the next sample */ - pState = pState + 1; - - /* Decrement the loop counter */ - blkCnt--; - } - - - /* Processing is complete. Now copy the last numTaps - 1 samples to the - * start of the state buffer. This prepares the state buffer for the - * next function call. */ - - /* Points to the start of the pState buffer */ - pStateCurnt = S->pState; - - /* Copy (numTaps - 1u) samples */ - tapCnt = (numTaps - 1u); - - /* Copy the data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - -#endif /* #ifndef ARM_MATH_CM0_FAMILY */ - -} - -/** - * @} end of LMS group - */ |