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matlaboctaveexponentiation

Vectorized exponentiation

I have two vectors, X of bases and N of exponents. I want to get the matrix of all values e = xn for each x in X and n in N.

For example, the following input:

X = [2 3 4]'
N = [1 2 3]

should produce:

ans = [2 4 8; 3 9 27; 4 16 64]

Is there a way to get this without looping (just like you can get all values of x×n by using the column by row product)?

Solution

  • Use bsxfun:

    bsxfun(@power, X, N)

    This assumes that X is a column vector and N is a row vector. If you want to guarantee that, use the following syntax which is more robust:

    bsxfun(@power, X(:), N(:).')