MATLAB: What does NaN mean here

Question

hi guys

I cannot understand what is happening when we are coding this;

K=0:0.01:1;

[rowK,colK]= size(K);

aux=zeros(colK,colK)+NaN;

In the auxiliary matrix which is being defined what role does NaN plays?

Thanks

Answer 1

Looks like the code intended to initialize a matrix filled with NaNs and does this by adding NaN to a zero matrix. Any number + NaN is NaN.

You could achieve the same effect with:

aux = NaN(colK);

One common reason you would use NaN instead of 0 is to differentiate when you actually have a value of 0 (say 0 Celsius) versus you have no idea what that value is.