[Israel.pm] Fwd: Perl PR in Israel [was Booking.com in Hebrew ]

Avishalom Shalit avishalom at gmail.com
Mon Jan 18 13:35:57 PST 2010


not exactly slides , but some reference to what i talked about two
meetings ago...

matlab code
with a few comments
-- vish




---------- Forwarded message ----------
From: Avishalom Shalit <avishalom at gmail.com>


hi,
here are the notes i went through in the talk
comments are in %

not sure this helps..
======
%% SOME EXAMPLES

% wavrecord - record audio into a numerical array
Fs=11025;
y  = wavrecord(2*Fs, Fs, 'double');

%wavplay  -play an array as raw audio

wavplay(y, Fs);
% reshape - a matrix into a differnt size, same number of elements one

yr=reshape(y,50,22050/50);

% column maximum
maxYr=max(yr);

% put the maximum colum value in all of the coulumm
maxYr=ones(50,1)*max(yr);
pl=(ones(50,1)*max(yr));

%plot the concatenated columns (the (:) operator retuns a 1D array,
reversing the reshape we did earlier)

% plot the piecewise maxima (the envelope)
plot(pl(:))
hold all
%plot the signal
plot(y)
%% speaking note F9 executes selected text, demonstrate on the "soundview"
% soundview(y,Fs) %% use f9


% histogram %
hist(y,40)
% auto correlogram
autocorr(y,400)
% FFT
f=fft(y);
plot(abs(f))
%% speaking note use of  "HELP "
help spectrogram

%% other general comments  using the GUI play with
%  zoom, 3d view shift, data label
% legend, add ellipse  , show properties , change ycolor to green

% you can also  do the same programatically
% eg..  set(gca,'ycolor','r')


%% other topics
% regular expressions
help regexp

%gui generation
guide

%step through debugger
dbstop if error
% also gui activated

%anonymous functions

f1_times_two=@(x)x*2;

% closure
f2_times_factor=@(factor)@(x)x*factor;

%f2_times_factor(2) behaves like f1_times_two

%% external toolboxes, e.g. datafeed tool
dftool
=====
-- vish


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