1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_lms_init_f32.c
4 * Description: Floating-point LMS filter initialization function
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/filtering_functions.h"
30
31 /**
32 @addtogroup LMS
33 @{
34 */
35
36 /**
37 @brief Initialization function for floating-point LMS filter.
38 @param[in] S points to an instance of the floating-point LMS filter structure
39 @param[in] numTaps number of filter coefficients
40 @param[in] pCoeffs points to coefficient buffer
41 @param[in] pState points to state buffer
42 @param[in] mu step size that controls filter coefficient updates
43 @param[in] blockSize number of samples to process
44
45 @par Details
46 <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
47 <pre>
48 {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
49 </pre>
50 The initial filter coefficients serve as a starting point for the adaptive filter.
51 <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_f32()</code>.
52 */
53
arm_lms_init_f32(arm_lms_instance_f32 * S,uint16_t numTaps,float32_t * pCoeffs,float32_t * pState,float32_t mu,uint32_t blockSize)54 ARM_DSP_ATTRIBUTE void arm_lms_init_f32(
55 arm_lms_instance_f32 * S,
56 uint16_t numTaps,
57 float32_t * pCoeffs,
58 float32_t * pState,
59 float32_t mu,
60 uint32_t blockSize)
61 {
62 /* Assign filter taps */
63 S->numTaps = numTaps;
64
65 /* Assign coefficient pointer */
66 S->pCoeffs = pCoeffs;
67
68 /* Clear state buffer and size is always blockSize + numTaps */
69 memset(pState, 0, (numTaps + (blockSize - 1)) * sizeof(float32_t));
70
71 /* Assign state pointer */
72 S->pState = pState;
73
74 /* Assign Step size value */
75 S->mu = mu;
76 }
77
78 /**
79 @} end of LMS group
80 */
81
