prod

Product of elements in an array

Usages

p = prod(A)

• If A is a scalar, P is equal to A.
• If A is a vector, p is the product of all elements along the longer dimension of A.
• Otherwise, each element of P is the product of all elements of the corresponding vector of A along the first non-singleton dimension.
• If A is empty, it returns an empty array.

p = prod(A, k)

• This is the same as the previous cases, except that each element of P corresponds to a vector of A along its k-th dimension.
• If the k-th dimension has zero length, then it returns an empty array.

💡 When multiplying numbers by prod, if any one of them is NaN, the result will be NaN.

Examples

• The total number of elements in an array a is given by the product of all elements in its size vector.

Input

% A random array.
a = rand(3,4,5,6,7,1,2);
% Product of all elements in the size vector.
n = prod(size(a))
% Using the built-in function numel.
numel(a)

Output

n = 
 5040.0

ans = 
 5040.0