Andrew Ng 's machine learning lecture note (5)

Vectorization

    Vectorization is a useful method to calculate. It may make the calculation much more faster in Octave/Matlab.So how to make our calculation vectorize.

    (1)When we see a add operator ,matrix by matrix should come to our mind.Especially ,For loops come to our mind and we should notice that maybe we should use vectorization.

    (2)When we see a formular. We should ask ourselve a question that can this part to be a matrix.