Stone Studio

I noticed that there are many people comparing Matlab with Maple, Mathematica etc. to find out what’s the best Maths package for them. But many of them didn’t realize the limitations of Matlab. I put up an article about the Birthday Problem in probability, If you try to solve it analytically like:
[cc lang='matlab' ]
1 – [...]

EigTool is a free MATLAB package for computing pseudospectra of dense and sparse matrices. It also provides a graphical interface to MATLAB’s built-in eigs routine (ARPACK) for large-scale eigenvalue computations. EigTool was developed from 1999 – 2002 by Thomas G. Wright at the Oxford University Computing Laboratory, under the direction of Nick Trefethen. The software [...]

The aim of the chebfun system is to “feel symbolic but run at the speed of numerics”. More precisely our vision is to achieve for functions what floating-point arithmetic achieves for numbers: rapid computation in which each successive operation is carried out exactly apart from a rounding error that is very small in relative terms [...]

COLEA: A software tool for speech analysis
PESQ and other objective measures for evaluating quality of speech processed by noise suppression algorithms [composite.zip]
            Relevant references:

Quality Assessment:   Hu, Y. and Loizou, P. (2008). “Evaluation of objective quality measures for speech enhancement,” IEEE Transactions on Speech and Audio Processing, 16(1), 229-238.

Intelligibility Assessment:  Ma, J., Hu, Y. [...]

A Simple Example
[cc lang="matlab"]
clear all; close all; clc;
f0 = 10;
N = 1024;
t = linspace(0,10,N); NFFT = 2^nextpow2(N);
fs = 1/(t(2)-t(1));
aa = 0.001:0.002:0.5; L = length(aa);
for kk = 1:L
a = aa(kk);
ff = f0 – a*t;
y = cos(2*pi*ff.*t);
periodogram(y,[],NFFT,fs); vline(f0); ylim([-50,2])
[...]

Assuming that the deterministic function y has additive Gaussian noise, evar(y) returns an estimated variance of this noise. A thin-plate smoothing spline model is used to smooth y. It is assumed that the model whose generalized cross-validation score is minimum can provide the variance of the additive noise. A few tests showed that evar works [...]

Damien Garcia has produced a 1-D to N-D robust smoothing matlab file to allow fast and robust smoothing of one-dimensional and multidimensional data w/wo missing values.
A simple example for signal:
y = cos(x/10)+(x/50).^2 + randn(size(x))/10;
y([70 75 80]) = [5.5 5 6];
is shown below:

In a continuous time domain, this might be like this:

You know [...]

cloudPlot will help visualize the distribution of a 2-dimensional dataset. It is especially helpful when looking at extremely large datasets where a redular plot(x,y,’.’) will just fill the plot with a solid color because the measurement points overlap each other. cloudPlot uses the built-in matlab routines to set the axis limits and grid points appropriate [...]