Category: Matlab

• Off-the-shelf optimization functions in Matlab

  Estimating a statistical model via maximum likelihood or MAP involves minimizing an error function – the negative log-likelihood or log-posterior. Generic functions built in to Matlab like fminunc and fmincon will often do the trick. There are many other free solvers available, which are often faster, or more powerful: Solvers by Mark Schmidt: there’s a huge collection of functions from Mark…

  September 13, 2014

• Fast 1D and 2D data binning in Matlab & Python

  I needed a fast method of binning 1D and 2D data in Matlab – that is, to compute the mean of z conditional on x being in a given range (1d binning) or the mean z of conditional on x and y being in given ranges (2d binning). I stumbled upon a clever method using…

  December 23, 2013

• Load pickle files in Matlab

  Updated March 2020 It’s easy enough to load .mat files in Python via the scipy.io.loadmat function. But what about loading .pickle files into Matlab? You need to do a little more work! It’s a bit roundabout, but if python is installed and on your path, you can call it from Matlab to save the data…

  June 12, 2013

• Whiten images in Matlab

  Previously, I showed how to whiten a matrix in Matlab. This involves finding the inverse square root of the covariance matrix of a set of observations, which is prohibitively expensive when the observations are high-dimensional – for instance, high-resolution natural images. Thankfully, it’s possible to whiten a set of natural images approximately by multiplying the…

  April 30, 2013

• Deinterlace a movie in Matlab

  Here’s a simple function to deinterlace a movie that was interlaced to go from 24fps to 30fps:

  April 23, 2013

• ipython and ipython notebook for Matlab users

  Following my post on IDEs for scientific Python, several commenters mentioned using some combination of their favorite text editor and ipython rather than a dedicated IDE. ipython is an interactive Python interpreter that offers a much enhanced user experience over the regular Python interpreter: with features such as: Integration with matplotlib Autocompletion Syntax highlighting at…

  April 19, 2013