Use channel for matrix and box counting

Question

This code is from the most popular go matrix package https://github.com/skelterjohn/go.matrix/blob/go1/util.go

I googled this function and seems like it is for computing the fractal dimension. But in this package, this function is never used so I am having a hard time understanding this.

func countBoxes(start, cap int) chan box {
        ints := make(chan box)
        go func() {
                for i := start; i < cap; i++ {
                        ints <- i
                }
                close(ints)
        }()
        return ints
}

Why do we need goroutine when we have only one anonymous function here? And does anybody know what this function does in terms of matrix work?

Thanks in advance.

Answer 1

It returns a channel with cap - start queued integer events. (i.e. You can 'read' start,start+1..,cap from the channel and then it closes ).

If you poke around in the code, it uses a similar kind of construct to create an iterator for the the indices of non-zero entries of sparse matrices. Look in sparse.go.

It's not used anywhere in the code that I can find, it may have been just to test the idea.