Exponential of big numbers

Dear Experts,

I need to compute the following formula: M= expm(atilde*T).

However, the atilde*t results in a matrix of big numbers and when I do the expm matlab gives back a matrix of NaN as it is not able to handle them (from my understanding). I tried with vpi from this toolbox (https://www.mathworks.com/matlabcentral/fileexchange/22725-variable-precision-integer-arithmetic) by doing M=expm(vpi(atilde*T)) but it doen't work as it gives me back the error that expm requires input of type double or single and instead the type is VPI.

Does anyone has a suggestion on how to deal with this problem?

Thank you so much!

Arianna

[Steven Lord]

How big are your "big numbers" in terms of magnitude?

Can you show a representative (small in terms of number of elements) matrix atilde*T?

Answer 1

[David Hill]

Try:

M=expm(vpa(atilde*T));

Answer 2

[Arianna Menardi]

Dear all, thank you for your suggestions! I actually found out that I needed to stabilize my matrix (dividing it by its max eigenvalue). Scaling it enabled my matlab to compute the code.

All the best