Find a function that sorts each ith element in the vector by the largest of the preceding elements.

Let x = [x_1, x_2, x_3, ..., x_N].

I want to make a vector y whose ith element is given as y_i = max {x_k | k<=i}.

For example, suppose that x is given as x=[1, 8, 3, 9, 11].

Then, I want to make y=[1, 8, 8, 9, 11].

Is there a function that does as above?

Actually, I can make a function that does as above, but I want to use built-in functions since the built-in functions are usually faster than my own.

Thank you for reading my question.

[Adam Danz]

If your x and y vectors are inputs, what's your expected output?

[Danny]

x is input and y is ouput.

[Adam Danz]

ah, right....

Looks like Steven Lord hit the nail on the head.

Answer 1

[Steven Lord]

The cummax function computes the cumulative maximum of an array.