387 lines
28 KiB
HTML
387 lines
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<h1 class="title">fastfouriertransformer.cpp Example File</h1>
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<span class="small-subtitle">demos/mobile/guitartuner/src/fastfouriertransformer.cpp</span>
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<!-- $$$demos/mobile/guitartuner/src/fastfouriertransformer.cpp-description -->
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<div class="descr"> <a name="details"></a>
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<pre class="cpp"> <span class="comment">/****************************************************************************
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**
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** Copyright (C) 2015 The Qt Company Ltd.
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** Contact: http://www.qt.io/licensing/
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**
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** This file is part of the QtDeclarative module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** You may use this file under the terms of the BSD license as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/</span>
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<span class="preprocessor">#include "fastfouriertransformer.h"</span>
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<span class="preprocessor">#include "math.h"</span>
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<span class="preprocessor">#define STIN inline</span>
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<span class="preprocessor">#define __STATIC</span>
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<span class="preprocessor">#include "fftpack.c"</span>
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<span class="comment">// called by __ogg_fdrffti</span>
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__STATIC <span class="type">void</span> drfti1(<span class="type">int</span> n<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>wa<span class="operator">,</span> <span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdrffti(<span class="type">int</span> n<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span> <span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdcosqi(<span class="type">int</span> n<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span> <span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="comment">// called by drftf1</span>
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STIN <span class="type">void</span> dradf2(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa1);
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<span class="comment">// called by drftf1</span>
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STIN <span class="type">void</span> dradf4(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa1<span class="operator">,</span>
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<span class="type">float</span> <span class="operator">*</span>wa2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa3);
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<span class="comment">// called by drftf1</span>
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STIN <span class="type">void</span> dradfg(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> ip<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">int</span> idl1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>c1<span class="operator">,</span>
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<span class="type">float</span> <span class="operator">*</span>c2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa);
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<span class="comment">// called by drftf1</span>
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STIN <span class="type">void</span> drftf1(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>c<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdrfftf(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>r<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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STIN <span class="type">void</span> dcsqf1(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>x<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>w<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>xh<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdcosqf(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>x<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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STIN <span class="type">void</span> dradb2(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa1);
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STIN <span class="type">void</span> dradb3(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa1<span class="operator">,</span>
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<span class="type">float</span> <span class="operator">*</span>wa2);
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STIN <span class="type">void</span> dradb4(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa1<span class="operator">,</span>
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<span class="type">float</span> <span class="operator">*</span>wa2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa3);
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STIN <span class="type">void</span> dradbg(<span class="type">int</span> ido<span class="operator">,</span><span class="type">int</span> ip<span class="operator">,</span><span class="type">int</span> l1<span class="operator">,</span><span class="type">int</span> idl1<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>cc<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>c1<span class="operator">,</span>
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<span class="type">float</span> <span class="operator">*</span>c2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>ch2<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wa);
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STIN <span class="type">void</span> drftb1(<span class="type">int</span> n<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>c<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>ch<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>wa<span class="operator">,</span> <span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdrfftb(<span class="type">int</span> n<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>r<span class="operator">,</span> <span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span> <span class="type">int</span> <span class="operator">*</span>ifac);
|
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STIN <span class="type">void</span> dcsqb1(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>x<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>w<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>xh<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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<span class="type">void</span> __ogg_fdcosqb(<span class="type">int</span> n<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>x<span class="operator">,</span><span class="type">float</span> <span class="operator">*</span>wsave<span class="operator">,</span><span class="type">int</span> <span class="operator">*</span>ifac);
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FastFourierTransformer<span class="operator">::</span>FastFourierTransformer(<span class="type"><a href="qobject.html">QObject</a></span> <span class="operator">*</span>parent) :
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|
<span class="type"><a href="qobject.html">QObject</a></span>(parent)<span class="operator">,</span>
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|
m_waveFloat(<span class="number">0</span>)<span class="operator">,</span>
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|
m_workingArray(<span class="number">0</span>)<span class="operator">,</span>
|
|
m_ifac(<span class="number">0</span>)<span class="operator">,</span>
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|
m_last_n(<span class="operator">-</span><span class="number">1</span>)
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|
{
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|
}
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FastFourierTransformer<span class="operator">::</span><span class="operator">~</span>FastFourierTransformer()
|
|
{
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|
<span class="keyword">if</span> (m_waveFloat <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
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|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_waveFloat;
|
|
}
|
|
<span class="keyword">if</span> (m_workingArray <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
|
|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_workingArray;
|
|
}
|
|
<span class="keyword">if</span> (m_ifac <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
|
|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_ifac;
|
|
}
|
|
}
|
|
|
|
<span class="comment">/**
|
|
* Prepares the arrays to be of length n.
|
|
*/</span>
|
|
<span class="type">void</span> FastFourierTransformer<span class="operator">::</span>reserve(<span class="type">int</span> n)
|
|
{
|
|
Q_ASSERT(n<span class="operator">></span><span class="number">0</span>);
|
|
<span class="keyword">if</span> (m_waveFloat <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
|
|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_waveFloat;
|
|
}
|
|
<span class="keyword">if</span> (m_workingArray <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
|
|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_workingArray;
|
|
}
|
|
<span class="keyword">if</span> (m_ifac <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
|
|
<span class="keyword">delete</span> <span class="operator">[</span><span class="operator">]</span> m_ifac;
|
|
}
|
|
m_workingArray <span class="operator">=</span> <span class="keyword">new</span> <span class="type">float</span><span class="operator">[</span><span class="number">2</span><span class="operator">*</span>n<span class="operator">+</span><span class="number">15</span><span class="operator">]</span>;
|
|
m_waveFloat <span class="operator">=</span> <span class="keyword">new</span> <span class="type">float</span><span class="operator">[</span>n<span class="operator">]</span>;
|
|
m_ifac <span class="operator">=</span> <span class="keyword">new</span> <span class="type">int</span><span class="operator">[</span>n<span class="operator">]</span>;
|
|
__ogg_fdrffti(n<span class="operator">,</span> m_workingArray<span class="operator">,</span> m_ifac);
|
|
m_last_n <span class="operator">=</span> n;
|
|
}
|
|
|
|
<span class="comment">/**
|
|
* Calculates the Fast Fourier Transformation (FFT).
|
|
*/</span>
|
|
<span class="type">void</span> FastFourierTransformer<span class="operator">::</span>calculateFFT(<span class="type"><a href="qlist.html">QList</a></span><span class="operator"><</span><span class="type"><a href="qtglobal.html#qint16-typedef">qint16</a></span><span class="operator">></span> wave)
|
|
{
|
|
<span class="keyword">const</span> <span class="type">int</span> n <span class="operator">=</span> wave<span class="operator">.</span>size();
|
|
<span class="keyword">if</span> (m_last_n <span class="operator">!</span><span class="operator">=</span> n) {
|
|
reserve(n);
|
|
}
|
|
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> n; i<span class="operator">+</span><span class="operator">+</span>) {
|
|
m_waveFloat<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">=</span> (<span class="type">float</span>) wave<span class="operator">.</span>at(i);
|
|
}
|
|
|
|
__ogg_fdrfftf(n<span class="operator">,</span> m_waveFloat<span class="operator">,</span> m_workingArray<span class="operator">,</span> m_ifac);
|
|
|
|
}
|
|
|
|
<span class="comment">/**
|
|
* Returns the index which corresponds to the maximum density
|
|
* of the FFT.
|
|
*/</span>
|
|
<span class="type">int</span> FastFourierTransformer<span class="operator">::</span>getMaximumDensityIndex()
|
|
{
|
|
<span class="keyword">const</span> <span class="type">int</span> halfN <span class="operator">=</span> m_last_n <span class="operator">/</span> <span class="number">2</span>;
|
|
<span class="type">float</span> maxDensity <span class="operator">=</span> <span class="number">0</span>;
|
|
<span class="type">int</span> maxDensityIndex <span class="operator">=</span> <span class="number">0</span>;
|
|
<span class="type">float</span> densitySquared <span class="operator">=</span> <span class="number">0.f</span>;
|
|
<span class="keyword">for</span> (<span class="type">int</span> k <span class="operator">=</span> <span class="number">1</span>; k <span class="operator"><</span> halfN; k<span class="operator">+</span><span class="operator">+</span>) {
|
|
<span class="comment">// Here, we calculate the frequency k/N.</span>
|
|
<span class="comment">// k=1, the wave oscillation time is N, and the frequency</span>
|
|
<span class="comment">// is 1/sample.</span>
|
|
<span class="comment">// k=2, the wave oscillation time is N/2, and the frequency</span>
|
|
<span class="comment">// is 2/sample.</span>
|
|
<span class="comment">// k=3, the wave oscillation time is N/3, and the frequency</span>
|
|
<span class="comment">// is 3/sample.</span>
|
|
<span class="comment">// Note, that the documentation is for Fortran, so indexes in the</span>
|
|
<span class="comment">// documentation does not match.</span>
|
|
<span class="comment">// The sine and cosine coefficients are obtained thus as follows:</span>
|
|
<span class="keyword">const</span> <span class="type">float</span> cosCoefficient <span class="operator">=</span> <a href="qtglobal.html#qAbs">qAbs</a>(m_waveFloat<span class="operator">[</span><span class="number">2</span><span class="operator">*</span>k<span class="operator">-</span><span class="number">1</span><span class="operator">]</span>);
|
|
<span class="keyword">const</span> <span class="type">float</span> sinCoefficient <span class="operator">=</span> <a href="qtglobal.html#qAbs">qAbs</a>(m_waveFloat<span class="operator">[</span><span class="number">2</span><span class="operator">*</span>k<span class="operator">]</span>);
|
|
|
|
densitySquared <span class="operator">=</span> sinCoefficient<span class="operator">*</span>sinCoefficient <span class="operator">+</span> cosCoefficient<span class="operator">*</span>cosCoefficient;
|
|
<span class="keyword">if</span> (densitySquared <span class="operator">></span> maxDensity) {
|
|
maxDensity <span class="operator">=</span> densitySquared;
|
|
maxDensityIndex <span class="operator">=</span> k;
|
|
}
|
|
}
|
|
|
|
<span class="keyword">if</span> (m_cutOffForDensitySquared <span class="operator"><</span> maxDensity) {
|
|
<span class="keyword">return</span> maxDensityIndex;
|
|
}
|
|
<span class="keyword">else</span> {
|
|
<span class="keyword">return</span> <span class="operator">-</span><span class="number">1</span>;
|
|
}
|
|
}
|
|
|
|
<span class="comment">/**
|
|
* Sets the cutoff density.
|
|
*/</span>
|
|
<span class="type">void</span> FastFourierTransformer<span class="operator">::</span>setCutOffForDensity(<span class="type">float</span> cutoff)
|
|
{
|
|
m_cutOffForDensitySquared <span class="operator">=</span> cutoff<span class="operator">*</span>cutoff;
|
|
}</pre>
|
|
</div>
|
|
<!-- @@@demos/mobile/guitartuner/src/fastfouriertransformer.cpp -->
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="ft">
|
|
<span></span>
|
|
</div>
|
|
</div>
|
|
<div class="footer">
|
|
<p>
|
|
<acronym title="Copyright">©</acronym> 2015 The Qt Company Ltd.
|
|
Documentation contributions included herein are the copyrights of
|
|
their respective owners.</p>
|
|
<br />
|
|
<p>
|
|
The documentation provided herein is licensed under the terms of the
|
|
<a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation
|
|
License version 1.3</a> as published by the Free Software Foundation.</p>
|
|
<p>
|
|
Documentation sources may be obtained from <a href="http://www.qt-project.org">
|
|
www.qt-project.org</a>.</p>
|
|
<br />
|
|
<p>
|
|
Qt and respective logos are trademarks of The Qt Company Ltd
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|
in Finland and/or other countries worldwide. All other trademarks are property
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of their respective owners. <a title="Privacy Policy"
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href="http://en.gitorious.org/privacy_policy/">Privacy Policy</a></p>
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