view mirex2012-matlab/getCQT.m @ 116:91bb029a847a timing

Reorder the calculations to match the series of vector operations in the most recent bqvec code, just in case it's the order of vector calculations that is saving the time rather than the avoidance of std::vector

function intCQT = getCQT(Xcqt,fSlice,tSlice,iFlag)
%outCQ = getCQT(Xcqt,fSlice,tSlice,iFlag) computes a rasterized representation of 
%the amplitudes of the calculated CQT coefficients for the frequency bins definded in vector fSlice and the 
%points in time (time frames) defined in vector tSlice using the interpolation method defined in iFlag. 
%Valid values for iFlag are:
%
%'linear'  ... linear interpolation (default)
%'spline'  ... spline interpolation
%'nearest' ... nearest neighbor interpolation
%'cubic'   ... piecewise cubic interpolation
%
%If the entire CQT representation should be rasterized, set fSlice and
%tSlice to 'all'.
%The input parameter Xcqt is the structure gained using cqt(...).
%The output parameter 'intCQT' is the same size as Xcqt.spCQT but is no
%longer sparse since the zeros between two coefficients are replaced by
%the interpolated values. The coefficients stored in 'intCQT' are now
%real-valued since only the absolute values of the coefficients are
%interpolated. If a spectrogram-like (rasterized) version of the CQT
%coefficients including phase information is required, use the function
%cqtPerfectRast() (see documentation for further information)
%
%Christian Schörkhuber, Anssi Klapuri 2010-06


if ischar(fSlice), fSlice = 1:(Xcqt.bins*Xcqt.octaveNr); end;
if ischar(tSlice)
    lastEnt = find(Xcqt.spCQT(1,:),1,'last');
    tSlice = 1:lastEnt;
end
if nargin < 4, iFlag = 'linear'; end;

intCQT = zeros(length(fSlice),length(tSlice));
bins = Xcqt.bins;
spCQT = Xcqt.spCQT;
octaveNr = Xcqt.octaveNr;
spCQT = spCQT.';

for k=1:length(fSlice)
   oct = octaveNr-floor((fSlice(k)-0.1)/bins);
   stepVec = 1:2^(oct-1):size(spCQT,1);
   Xbin = full(spCQT(stepVec,fSlice(k)));
   intCQT(k,:) = interp1(stepVec,abs(Xbin),tSlice,iFlag);
end