coherencysegcpt.m 5.3 KB

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  1. function [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegcpt(data1,data2,win,params,segave,fscorr)
  2. % Multi-taper coherency,cross-spectrum and individual spectra computed by segmenting
  3. % two univariate time series into chunks - continuous and point process stored as times
  4. %
  5. % Usage:
  6. % [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencysegcpt(data1,data2,win,params,segave,fscorr)
  7. % Input:
  8. % Note units have to be consistent. See chronux.m for more information.
  9. % data1 (column vector, continuous data) -- required
  10. % data2 (1d structure array of spike times; also accepts 1d array of spike times) -- required
  11. % params: structure with fields tapers, pad, Fs, fpass, err
  12. % - optional
  13. % tapers : precalculated tapers from dpss or in the one of the following
  14. % forms:
  15. % (1) A numeric vector [TW K] where TW is the
  16. % time-bandwidth product and K is the number of
  17. % tapers to be used (less than or equal to
  18. % 2TW-1).
  19. % (2) A numeric vector [W T p] where W is the
  20. % bandwidth, T is the duration of the data and p
  21. % is an integer such that 2TW-p tapers are used. In
  22. % this form there is no default i.e. to specify
  23. % the bandwidth, you have to specify T and p as
  24. % well. Note that the units of W and T have to be
  25. % consistent: if W is in Hz, T must be in seconds
  26. % and vice versa. Note that these units must also
  27. % be consistent with the units of params.Fs: W can
  28. % be in Hz if and only if params.Fs is in Hz.
  29. % The default is to use form 1 with TW=3 and K=5
  30. %
  31. % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...).
  32. % -1 corresponds to no padding, 0 corresponds to padding
  33. % to the next highest power of 2 etc.
  34. % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
  35. % to 512 points, if pad=1, we pad to 1024 points etc.
  36. % Defaults to 0.
  37. % Fs (sampling frequency) - optional. Default 1.
  38. % fpass (frequency band to be used in the calculation in the form
  39. % [fmin fmax])- optional.
  40. % Default all frequencies between 0 and Fs/2
  41. % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
  42. % [0 p] or 0 - no error bars) - optional. Default 0.
  43. % segave (average over segments for 1, don't average for 0)- optional. Default 1
  44. % fscorr (finite size corrections, 0 (don't use finite size corrections) or
  45. % 1 (use finite size corrections) - optional
  46. % (available only for spikes). Defaults 0.
  47. % Output:
  48. % C (magnitude of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
  49. % phi (phase of coherency - frequencies x segments if segave=0; dimension frequencies if segave=1)
  50. % S12 (cross spectrum - frequencies x segments if segave=0; dimension frequencies if segave=1)
  51. % S1 (spectrum 1 - frequencies x segments if segave=0; dimension frequencies if segave=1)
  52. % S2 (spectrum 2 - frequencies x segments if segave=0; dimension frequencies if segave=1)
  53. % f (frequencies)
  54. % zerosp (1 for trials where no spikes were found, 0 otherwise)
  55. % confC (confidence level for C at 1-p %) - only for err(1)>=1
  56. % phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi
  57. % Note that phi + 2 phistd and phi - 2 phistd will give 95% confidence
  58. % bands for phi - only for err(1)>=1
  59. % Cerr (Jackknife error bars for C - use only for Jackknife - err(1)=2)
  60. if nargin < 3; error('Need data1 and data2 and size of segment'); end;
  61. if nargin < 4; params=[]; end;
  62. [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
  63. if nargin < 5 || isempty(segave); segave=1;end;
  64. if nargin < 6 || isempty(fscorr); fscorr=0; end;
  65. if nargout > 7 && err(1)==0;
  66. % Errors computed only if err(1) is non-zero. Need to change params and run again.
  67. error('When errors are desired, err(1) has to be non-zero.');
  68. end;
  69. if nargout > 9 && err(1)~=2;
  70. error('Cerr computed only for Jackknife. Correct inputs and run again');
  71. end;
  72. N=check_consistency(data1,data2,1);
  73. dt=1/Fs; % sampling interval
  74. T=N*dt; % length of data in seconds
  75. E=0:win:T-win; % fictitious event triggers
  76. win=[0 win]; % use window length to define left and right limits of windows around triggers
  77. data1=createdatamatc(data1,E,Fs,win); % segmented data 1
  78. data2=createdatamatpt(data2,E,win); % segmented data 2
  79. params.trialave=segave;
  80. if nargout==7;
  81. [C,phi,S12,S1,S2,f,zerosp]=coherencycpt(data1,data2,params,fscorr); % compute coherency for segmented data
  82. elseif nargout==9;
  83. [C,phi,S12,S1,S2,f,zerosp,confC,phistd]=coherencycpt(data1,data2,params,fscorr); % compute coherency for segmented data
  84. elseif nargout==10;
  85. [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencycpt(data1,data2,params,fscorr); % compute coherency for segmented data
  86. end;