Matrix sum

Hi,

I'm dealing with a condition in a while loop that I can't get it right. Here is the example:

Given the initial matrix of P=[2 3 8;1 -3 6;-2 -1 0], calculate the e^P = sum(P^k/k!) which k=[0:N-1]. Now the question is how can I implant the sum in matlab? Also, using a while loop, I want to address each element of matrix to meet a condition (e.g. each element of P bigger than 0.5) how can I do that?

Answer 1

[Walter Roberson]

eP = zeros(size(P));
for k = 0:N-1
  eP = eP + P^k ./ k!;
end

For your second question, you need to indicate what condition should be used to terminate the "while" loop. Detection of the first element which is not greater than 0.5 ? Detection that you have run out of elements? Which order do you want to visit the elements in, considering that P will be a 2D matrix and thus could be traveled randomly or by rows or by columns or by diagonals or by Knight moves...