Re: Using reduce() with tuples created by zip()

[Craig Dillabaugh]

On Thursday, 31 October 2013 at 19:23:56 UTC, Philippe Sigaud
wrote:

I think reduce takes two arguments: the growing seed and the current front. You're trying to get (a[0]-b[0])^^2 + (a[1]-b[1])^^2 + ..., right?

Yep. The (e[1]-e[0])*(e[1]-e[0]) bit was, I supposed was
effectively
calculating (a[0]-b[0])^^2 and so on.  I forgot about the ^^2 in
D.

Try this:

module euclid;


import std.stdio;

double euclid_dist( double[] pt1, double[] pt2 ) {
    assert( pt1.length == pt2.length );
    import std.algorithm;
    import std.math;
    import std.range;

return sqrt(0.0.reduce!( (sum,pair) => sum + (pair[0]-pair[1])^^2

)(zip(pt1, pt2)));
}

void main()
{
    double[] arr1 = [0.0, 1.0, 0.1];
    double[] arr2 = [1.0, -1.0, 0.0];
    writeln(euclid_dist(arr1,arr2));
}



On Thu, Oct 31, 2013 at 8:12 PM, Craig Dillabaugh <
cdill...@cg.scs.carleton.ca> wrote:

clip

Cheers,
Craig

Thanks, I will try both your, and Bearophile's ideas and see if I
can figure out how they work.
Craig