123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174 |
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
- "http://www.w3.org/TR/REC-html40/loose.dtd">
- <html>
- <head>
- <title>Description of CrossSpecMat</title>
- <meta name="keywords" content="CrossSpecMat">
- <meta name="description" content="">
- <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
- <meta name="generator" content="m2html © 2005 Guillaume Flandin">
- <meta name="robots" content="index, follow">
- <link type="text/css" rel="stylesheet" href="../../m2html.css">
- <script type="text/javascript">
- if (top.frames.length == 0) { top.location = "../../index.html"; };
- </script>
- </head>
- <body>
- <a name="_top"></a>
- <!-- ../menu.html chronux_2_10 --><!-- menu.html old -->
- <h1>CrossSpecMat
- </h1>
- <h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../../up.png"></a></h2>
- <div class="box"><strong></strong></div>
- <h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../../up.png"></a></h2>
- <div class="box"><strong>function [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMat(data,win,params) </strong></div>
- <h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../../up.png"></a></h2>
- <div class="fragment"><pre class="comment">
- Multi-taper cross-spectral matrix - another routine, this one allows for multiple trials and channels
- but does not do confidence intervals. Also this routine always averages over trials - continuous process
- Usage:
- [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMat(data,win,params)
- Input:
- Note units have to be consistent. See chronux.m for more information.
- data (in form samples x channels x trials)
- win (duration of non-overlapping window)
- params: structure with fields tapers, pad, Fs, fpass
- - optional
- tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional.
- If not specified, use [NW K]=[3 5]
- pad (padding factor for the FFT) - optional. Defaults to 0.
- e.g. For N = 500, if PAD = 0, we pad the FFT
- to 512 points; if PAD = 2, we pad the FFT
- to 2048 points, etc.
- Fs (sampling frequency) - optional. Default 1.
- fpass (frequency band to be used in the calculation in the form
- [fmin fmax])- optional.
- Default all frequencies between 0 and Fs/2
- Output:
- Sc (cross spectral matrix frequency x channels x channels)
- Cmat Coherence matrix frequency x channels x channels
- Ctot Total coherence: SV(1)^2/sum(SV^2) (frequency)
- Cvec leading Eigenvector (frequency x channels)
- Cent A different measure of total coherence: GM/AM of SV^2s
- f (frequencies)</pre></div>
- <!-- crossreference -->
- <h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../../up.png"></a></h2>
- This function calls:
- <ul style="list-style-image:url(../../matlabicon.gif)">
- <li><a href="../../chronux_2_10/spectral_analysis/continuous/mtfftc.html" class="code" title="function J=mtfftc(data,tapers,nfft,Fs)">mtfftc</a> Multi-taper fourier transform - continuous data</li><li><a href="../../chronux_2_10/spectral_analysis/helper/dpsschk.html" class="code" title="function [tapers,eigs]=dpsschk(tapers,N,Fs)">dpsschk</a> Helper function to calculate tapers and, if precalculated tapers are supplied,</li><li><a href="../../chronux_2_10/spectral_analysis/helper/getfgrid.html" class="code" title="function [f,findx]=getfgrid(Fs,nfft,fpass)">getfgrid</a> Helper function that gets the frequency grid associated with a given fft based computation</li><li><a href="../../chronux_2_10/spectral_analysis/helper/getparams.html" class="code" title="function [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params)">getparams</a> Helper function to convert structure params to variables used by the</li></ul>
- This function is called by:
- <ul style="list-style-image:url(../../matlabicon.gif)">
- </ul>
- <!-- crossreference -->
- <h2><a name="_source"></a>SOURCE CODE <a href="#_top"><img alt="^" border="0" src="../../up.png"></a></h2>
- <div class="fragment"><pre>0001 <a name="_sub0" href="#_subfunctions" class="code">function [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMat(data,win,params)</a>
- 0002 <span class="comment">%</span>
- 0003 <span class="comment">%</span>
- 0004 <span class="comment">% Multi-taper cross-spectral matrix - another routine, this one allows for multiple trials and channels</span>
- 0005 <span class="comment">% but does not do confidence intervals. Also this routine always averages over trials - continuous process</span>
- 0006 <span class="comment">%</span>
- 0007 <span class="comment">% Usage:</span>
- 0008 <span class="comment">%</span>
- 0009 <span class="comment">% [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMat(data,win,params)</span>
- 0010 <span class="comment">% Input:</span>
- 0011 <span class="comment">% Note units have to be consistent. See chronux.m for more information.</span>
- 0012 <span class="comment">% data (in form samples x channels x trials)</span>
- 0013 <span class="comment">% win (duration of non-overlapping window)</span>
- 0014 <span class="comment">% params: structure with fields tapers, pad, Fs, fpass</span>
- 0015 <span class="comment">% - optional</span>
- 0016 <span class="comment">% tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional.</span>
- 0017 <span class="comment">% If not specified, use [NW K]=[3 5]</span>
- 0018 <span class="comment">% pad (padding factor for the FFT) - optional. Defaults to 0.</span>
- 0019 <span class="comment">% e.g. For N = 500, if PAD = 0, we pad the FFT</span>
- 0020 <span class="comment">% to 512 points; if PAD = 2, we pad the FFT</span>
- 0021 <span class="comment">% to 2048 points, etc.</span>
- 0022 <span class="comment">% Fs (sampling frequency) - optional. Default 1.</span>
- 0023 <span class="comment">% fpass (frequency band to be used in the calculation in the form</span>
- 0024 <span class="comment">% [fmin fmax])- optional.</span>
- 0025 <span class="comment">% Default all frequencies between 0 and Fs/2</span>
- 0026 <span class="comment">% Output:</span>
- 0027 <span class="comment">% Sc (cross spectral matrix frequency x channels x channels)</span>
- 0028 <span class="comment">% Cmat Coherence matrix frequency x channels x channels</span>
- 0029 <span class="comment">% Ctot Total coherence: SV(1)^2/sum(SV^2) (frequency)</span>
- 0030 <span class="comment">% Cvec leading Eigenvector (frequency x channels)</span>
- 0031 <span class="comment">% Cent A different measure of total coherence: GM/AM of SV^2s</span>
- 0032 <span class="comment">% f (frequencies)</span>
- 0033 d=ndims(data);
- 0034 <span class="keyword">if</span> d<2, error(<span class="string">'Need multidimensional array'</span>); <span class="keyword">end</span>
- 0035 <span class="keyword">if</span> d==2, [N,C]=size(data); <span class="keyword">end</span>;
- 0036 <span class="keyword">if</span> d==3, [N,C,Ntr]=size(data); <span class="keyword">end</span>;
- 0037 <span class="keyword">if</span> nargin < 3; params=[]; <span class="keyword">end</span>;
- 0038 [tapers,pad,Fs,fpass,err,trialave,params]=<a href="../../chronux_2_10/spectral_analysis/helper/getparams.html" class="code" title="function [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params)">getparams</a>(params);
- 0039 clear err trialave params
- 0040 nwin=round(win*Fs); nfft=2^(nextpow2(nwin)+pad);
- 0041 [f,findx]=<a href="../../chronux_2_10/spectral_analysis/helper/getfgrid.html" class="code" title="function [f,findx]=getfgrid(Fs,nfft,fpass)">getfgrid</a>(Fs,nfft,fpass);
- 0042 tapers=<a href="../../chronux_2_10/spectral_analysis/helper/dpsschk.html" class="code" title="function [tapers,eigs]=dpsschk(tapers,N,Fs)">dpsschk</a>(tapers,nwin,Fs); <span class="comment">% check tapers</span>
- 0043 Sc=zeros(length(findx),C,C);
- 0044
- 0045 Nwins=floor(N/nwin);
- 0046
- 0047 <span class="keyword">if</span> d==3, <span class="comment">% If there are multiple trials</span>
- 0048 <span class="keyword">for</span> iwin=1:Nwins,
- 0049 <span class="keyword">for</span> i=1:Ntr,
- 0050 data1=squeeze(data(1+(iwin-1)*nwin:iwin*nwin,:,i));
- 0051 J1=<a href="../../chronux_2_10/spectral_analysis/continuous/mtfftc.html" class="code" title="function J=mtfftc(data,tapers,nfft,Fs)">mtfftc</a>(detrend(data1),tapers,nfft,Fs);
- 0052 J1=J1(findx,:,:);
- 0053 <span class="keyword">for</span> k=1:C,
- 0054 <span class="keyword">for</span> l=1:C,
- 0055 spec=squeeze(mean(conj(J1(:,:,k)).*J1(:,:,l),2));
- 0056 Sc(:,k,l)=Sc(:,k,l)+spec;
- 0057 <span class="keyword">end</span>
- 0058 <span class="keyword">end</span>
- 0059 <span class="keyword">end</span>
- 0060 <span class="keyword">end</span>
- 0061 Sc=Sc/(Nwins*Ntr);
- 0062 <span class="keyword">end</span>
- 0063
- 0064 <span class="keyword">if</span> d==2, <span class="comment">% only one trial</span>
- 0065 <span class="keyword">for</span> iwin=1:Nwins,
- 0066 data1=squeeze(data(1+(iwin-1)*nwin:iwin*nwin,:));
- 0067 J1=<a href="../../chronux_2_10/spectral_analysis/continuous/mtfftc.html" class="code" title="function J=mtfftc(data,tapers,nfft,Fs)">mtfftc</a>(data1,tapers,nfft,Fs);
- 0068 J1=J1(findx,:,:);
- 0069 <span class="keyword">for</span> k=1:C,
- 0070 <span class="keyword">for</span> l=1:C,
- 0071 Sc(:,k,l)=Sc(:,k,l)+squeeze(mean(conj(J1(:,:,k)).*J1(:,:,l),2));
- 0072 <span class="keyword">end</span>
- 0073 <span class="keyword">end</span>
- 0074 <span class="keyword">end</span>
- 0075 Sc=Sc/Nwins;
- 0076 <span class="keyword">end</span>
- 0077
- 0078 Cmat=Sc;
- 0079 Sdiag=zeros(length(findx),C);
- 0080 <span class="keyword">for</span> k=1:C,
- 0081 Sdiag(:,k)=squeeze(Sc(:,k,k));
- 0082 <span class="keyword">end</span>
- 0083
- 0084 <span class="keyword">for</span> k=1:C,
- 0085 <span class="keyword">for</span> l=1:C,
- 0086 Cmat(:,k,l)=Sc(:,k,l)./sqrt(abs(Sdiag(:,k).*Sdiag(:,l)));
- 0087 <span class="keyword">end</span>
- 0088 <span class="keyword">end</span>
- 0089
- 0090 Ctot=zeros(length(findx),1); Cent=Ctot;
- 0091 Cvec=zeros(length(findx),C);
- 0092 <span class="keyword">for</span> i=1:length(findx),
- 0093 [u s]=svd(squeeze(Sc(i,:,:)));s=diag(s);
- 0094 Ctot(i)=s(1).^2/sum(s.^2); Cent(i)=exp(mean(log(s.^2)))/mean(s.^2);
- 0095 Cvec(i,:)=transpose(u(:,1));
- 0096
- 0097 <span class="keyword">end</span>
- 0098</pre></div>
- <hr><address>Generated on Fri 12-Aug-2011 11:36:15 by <strong><a href="http://www.artefact.tk/software/matlab/m2html/" target="_parent">m2html</a></strong> © 2005</address>
- </body>
- </html>
|