Yuncong's Matlab tricks

From SeedWiki

• Claim symbols to be real

a = sym('a','real');

• Substitute sub-expressions in symbolic calculations:

M = (x^2+y^2)^(1/2)*sin(alpha + atan2(y,x));
d = (x^2+y^2)^(1/2);
theta = alpha + atan2(y,x);
q = simplify(feval(symengine,'subsex',M,[char(d) '=d,' char(theta) '=theta']));

• atan2 for symbolic calculations:

http://en.wikipedia.org/wiki/Atan2#Definition

• Read data from formatted text

http://www.mathworks.com/matlabcentral/fileexchange/10946-readtext

• Linux launcher

matlab -desktop &

• Remove empty elements in a cell

result = c(~cellfun('isempty',c))