What is NaNi, and how is it different fron NaN?

I am writing a function in Matlab. There should be something wrong. The output of my f开发者_开发问答unction is a vector. When I see every element of my vector I see NaN (Not a Number) and NaNi, that really I don´t Know?

Does anybody know what is NaNi?

NaNi is an imaginary Not-A-Number:

>>NaN*i
ans =
            0 +        NaNi

Actually NaNi does not exist in Matlab.

when you have a complex number, the displayed values are 'the real part' + 'the complex part' + 'i'. This is shown without a space before the i, try:

(-1)^0.5   %This will give 0.0000 + 1.0000i

This means that if the complex part of the number is NaN, it is printed together with i and appears to be a single word NaNi. For example:

NaN*(1+i)   % This will give NaN +    NaNi
x = NaN*i   % This will give 0 +    NaNi

You will find that it is not possible to separately evaluate NaNi or multiply it with 1.

Furthermore the expected outputs are produced when inspecting the result:

real(x) % This will give 0
imag(x) % This will give NaN