How can I simplify/vectorize this nested loop version of pascals triangle?

%mypascal

n = input('Enter a value for n: ');

% create matrix using nested loops (programming method)

 somemat = ones(n);

 for i = 2:n
     for j = 2:n
         somemat(i,j) = somemat(i-1,j) + somemat(i, j-1);
     end
 end

[Stephen23]

@Mark Nelson: is there a specific problem with using a loop?

[Mark Nelson]

No, I'm just wondering if there is a built in function (like meshgrid) that will do it in one step.

Answer 1

[OCDER]

Behold, a function called pascal

https://www.mathworks.com/help/matlab/ref/pascal.html

S = pascal(n)

[Mark Nelson]

@OCDER obviously not what I'm looking for. Perhaps there is no easier way. Thanks anyway.

[OCDER]

Yeah, I don't think you can vectorize it completely, otherwise Mathwork's pascal would have shown the vectorized code. Since the pascal triangle is symmetric, you could vectorize the filling of the other half of the triangle, which will speed up the code.

For n = 2000, pascal.m is ~ 5 times faster than your pure for loop approach.