Home > chronux_1_50 > pointtimes > coherencysegpt.m

coherencysegpt

PURPOSE ^

Multi-taper coherency computed by segmenting two univariate point processes

SYNOPSIS ^

function [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegpt(data1,data2,win,params,segave,fscorr)

DESCRIPTION ^

 Multi-taper coherency computed by segmenting two univariate point processes
 into chunks

 Usage:
 [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegpt(data1,data2,win,params,segave,fscorr)
 Input: 
 Note units have to be consistent. See chronux.m for more information.
       data1 (1d structure array of spike times; also accepts 1d array of spike times) -- required
       data2 (1d structure array of spike times; also accepts 1d array of spike times) -- required
       win   (length of segments) - required
       params: structure with fields tapers, pad, Fs, fpass, err
       - 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 (can take values -1,0,1,2...). 
                    -1 corresponds to no padding, 0 corresponds to padding
                    to the next highest power of 2 etc.
                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
                       to 512 points, if pad=1, we pad to 1024 points etc.
                       Defaults to 0.
           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
           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
                                   [0 p] or 0 - no error bars) - optional. Default 0.
       segave - optional 0 for don't average over segments, 1 for average - default
       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
                (available only for spikes). Defaults 0.
 Output:
       C (magnitude of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
       phi (phase of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
       S12 (cross spectrum -  frequencies x segments if segave=0; dimension frequencies if segave=1)
       S1 (spectrum 1 - frequencies x segments if segave=0; dimension frequencies if segave=1)
       S2 (spectrum 2 - frequencies x segments if segave=0; dimension frequencies if segave=1)
       f (frequencies)
       zerosp (1 for segments where no spikes were found, 0 otherwise)
       confC (confidence level for C at 1-p %) - only for err(1)>=1
       phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi - Note that 
                phi + 2 phistd and phi - 2 phistd will give 95% confidence
                bands for phi - only for err(1)>=1 
       Cerr  (Jackknife error bars for C - use only for Jackknife - err(1)=2)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegpt(data1,data2,win,params,segave,fscorr)
0002 % Multi-taper coherency computed by segmenting two univariate point processes
0003 % into chunks
0004 %
0005 % Usage:
0006 % [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegpt(data1,data2,win,params,segave,fscorr)
0007 % Input:
0008 % Note units have to be consistent. See chronux.m for more information.
0009 %       data1 (1d structure array of spike times; also accepts 1d array of spike times) -- required
0010 %       data2 (1d structure array of spike times; also accepts 1d array of spike times) -- required
0011 %       win   (length of segments) - required
0012 %       params: structure with fields tapers, pad, Fs, fpass, err
0013 %       - optional
0014 %           tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0015 %                                                 specified, use [NW K]=[3 5]
0016 %            pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
0017 %                    -1 corresponds to no padding, 0 corresponds to padding
0018 %                    to the next highest power of 2 etc.
0019 %                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
0020 %                       to 512 points, if pad=1, we pad to 1024 points etc.
0021 %                       Defaults to 0.
0022 %           Fs   (sampling frequency) - optional. Default 1.
0023 %           fpass    (frequency band to be used in the calculation in the form
0024 %                                   [fmin fmax])- optional.
0025 %                                   Default all frequencies between 0 and Fs/2
0026 %           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
0027 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0028 %       segave - optional 0 for don't average over segments, 1 for average - default
0029 %       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
0030 %                (available only for spikes). Defaults 0.
0031 % Output:
0032 %       C (magnitude of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
0033 %       phi (phase of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
0034 %       S12 (cross spectrum -  frequencies x segments if segave=0; dimension frequencies if segave=1)
0035 %       S1 (spectrum 1 - frequencies x segments if segave=0; dimension frequencies if segave=1)
0036 %       S2 (spectrum 2 - frequencies x segments if segave=0; dimension frequencies if segave=1)
0037 %       f (frequencies)
0038 %       zerosp (1 for segments where no spikes were found, 0 otherwise)
0039 %       confC (confidence level for C at 1-p %) - only for err(1)>=1
0040 %       phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi - Note that
0041 %                phi + 2 phistd and phi - 2 phistd will give 95% confidence
0042 %                bands for phi - only for err(1)>=1
0043 %       Cerr  (Jackknife error bars for C - use only for Jackknife - err(1)=2)
0044 
0045 
0046 if nargin < 3; error('Need data1 and data2 and size of segment'); end;
0047 if nargin < 4; params=[]; end;
0048 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0049 clear tapers pad fpass trialave
0050 if nargin < 5 || isempty(segave); segave=1;end;
0051 if nargin < 6 || isempty(fscorr); fscorr=0; end;
0052 
0053 if nargout > 9 && err(1)~=2; 
0054     error('Cerr computed only for Jackknife. Correct inputs and run again');
0055 end;
0056 if nargout > 7 && err(1)==0;
0057     error('Errors computed only if err(1) is not equal to zero');
0058 end;
0059 
0060 check_consistency(data1,data2);
0061 [mintime1,maxtime1]=minmaxsptimes(data1);
0062 [mintime2,maxtime2]=minmaxsptimes(data2);
0063 mintime=min(mintime1,mintime2);
0064 maxtime=max(maxtime1,maxtime2);
0065 % dt=1/Fs;
0066 % t=mintime:dt:maxtime+dt; % time grid for prolates
0067 % N=length(t); % number of points in grid for dpss
0068 
0069 E=mintime:win:maxtime; % fictitious event triggers
0070 win=[0 win]; % use window length to define left and right limits of windows around triggers
0071 data1=createdatamatpt(data1,E,win); % segmented data 1
0072 data2=createdatamatpt(data2,E,win); % segmented data 2
0073 params.trialave=segave;
0074 if err(1)==0;
0075    [C,phi,S12,S1,S2,f,zerosp]=coherencypt(data1,data2,params,fscorr); % compute coherency for segmented data
0076 elseif err(1)==1;
0077    [C,phi,S12,S1,S2,f,zerosp,confC,phistd]=coherencypt(data1,data2,params,fscorr); % compute coherency for segmented data
0078 elseif err(1)==2;
0079    [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencypt(data1,data2,params,fscorr); % compute coherency for segmented data
0080 end;

Generated on Mon 09-Oct-2006 00:54:52 by m2html © 2003