14 Jun 2018

Get Matlab Version


Matlab provides loads of useful functions for scientific computing. However, the functions might be added or deprecated from version to version. To write more robust codes, it's always a good practice to deal with different cases. An if...else... clause would be enough for this purpose.

9 Feb 2018

Get the latest release folder from a directory

Sometimes, we might need to find the latest release folder from a software repository according to the time stamp of the folder property. This could be done by extracting all the time stamps and sort them accordingly. MATLAB provides several function to do this nicely.

16 Jan 2018

Scroll to the last line of text edit in Matlab

Matlab's edit UIControl provide some flexibilities for displaying information, while setting the Max-Min>1 it supports multiple line. However, the caret is alwasy set to 0 position in the first line which is very annoy while you would like to show dynamic updated information to the user. To implement this capability, the underlying Java class has to be digged out. Yair M. Altman's findjobj.m function works perfectly to obtain those kind of information. Then, all we need to do is providing the Matlab UIControl's handle and set caret to the document length.

22 Dec 2017

Maxmise plot in matplotlib


To make the plot maxmised, different commands need to be used according to the current backends used by matplotlib:

Save plot without displaying in Matplotlib

By using Matplotlib, data can be easily plotted in the same way as in Matlab. But sometimes you might need to plot thousands of plots in a bug loop and save those intermediate results. The interactive display could be an issue that makes your machine not only slow but also useless. Someone suggests 'plt.ioff()' to turn off interactive mode. It may work in some cases (according to the feedbacks on Stackoverflow). For me, no magic happened. After searching the internet, the most straightforward solution would be...

15 Jun 2017

Finding Intersection Point(s) of Two Circles

This is a very common problem of finding the intersection point(s) of two circles. Visually, it is easy to define the three cases: no intersection, touching (single intersection point), and two intersection points. Analytically, mathematical calculations are required to work out the exact intersection position(s) (if any) by using the equations of the two circles. A more detailed explanation could be find from HERE and HERE.

Below, it's my implementation in Matlab. The inputs are c1 and c2, which are both vectors representing a circle in the format of [x,y,d]. The output is the point list matrix sorted using y coordinates. If there is no intersection, it is an empty matrix. For touching case, it is a single-row matrix (or vector) in the format of [x,y]. Otherwise, it is a 2*2 matrix forming by the coordinates of the two intersection points: [x1,y1;x2,y2].