Find location of current m-file in MATLAB
mfilename or better mfilename(‘fullpath’)
matlab
Stable accumarray in MATLAB
We can use sortrows as a preprocessing step to sort the indices and corresponding values first, as its documentation states: SORTROWS uses a stable version of quicksort. As the subscripts in subs should be sorted with respect to their linear indices, we need to sort them in reverse lexicographic order. This can be achieved by … Read more
Access m-files in a subfolder without permanently adding it to the path
Add path to the top of MATLAB search paths for current MATLAB session only – addpath(PATHNAME) Same as addpath, but stays good for next sessions – savepath(PATHNAME) Add all subdirectories for current MATLAB session only – addpath(genpath(PATHNAME)) Note: One must be careful while adding paths because if there are multiple function files with the same … Read more
How to divide an image into blocks in MATLAB?
Since blockproc (and the deprecated blkproc) are both functions in the Image Processing Toolbox, I thought I’d add a basic MATLAB solution that requires no additional toolboxes… If you want to divide a matrix into submatrices, one way is to use mat2cell to break the matrix up and store each submatrix in a cell of … Read more
Generate a random number in a certain range in MATLAB
If you are looking for Uniformly distributed pseudorandom integers use: randi([13, 20])
Get the indices of the n largest elements in a matrix
There are a couple ways you can do this depending on how you want to deal with repeated values. Here’s a solution that finds indices for the 5 largest values (which could include repeated values) using sort: [~, sortIndex] = sort(A(:), ‘descend’); % Sort the values in descending order maxIndex = sortIndex(1:5); % Get a … Read more
Matlab – PCA analysis and reconstruction of multi dimensional data
Here’s a quick walkthrough. First we create a matrix of your hidden variables (or “factors”). It has 100 observations and there are two independent factors. >> factors = randn(100, 2); Now create a loadings matrix. This is going to map the hidden variables onto your observed variables. Say your observed variables have four features. Then … Read more
Matlab ode solvers: changing state and specified time
Inserting large discontinuities in your ODE in the way you suggest (and the way illustrated by @macduff) can lead to less precision and longer computation times (especially with ode45 – ode15s might be a better option or at least make sure that your absolute and relative tolerances are suitable). You’ve effectively produced a very stiff … Read more
Recursive Anonymous Function Matlab
We found two possibilites now, both rely on the use of cell arrays. Note that this might not work in Octave. The key was an implementation of a case distinction. The first one that I found, can be found here. This method makes use of matlabs boolean values, true can be evaluated as 1 while … Read more
character reconstruction and filling for OCR
I have played a bit with your input Normalization of lighting + dynamic range normalization helps a bit to obtain much better results but still far away from needed one. I would like to try sharpening of partial derivations to boost the letters from background and treshold out small bumps before integrate back and recolor … Read more