Personally, I like the node count because it encourages to use meaningful variable names. A variable with a name ‘d’ has the same node count as using name ‘distance’, but latter clearly is more readable.

Yi

You bring up an interesting point about metrics on code. If people were to specify metrics to judge code on, how would they be defined?

* Binary (works/does not work)
* Length (MATLAB golf)
* Node count
* Community “thumbs up/down” voting (not automatable)

Are there automatable metrics that could be used to give an idea of what code is best? Personally, I think Golf is an interesting challenge, but I prefer readability by making variable with descriptive names on separate lines:

flagIsBig = (variable > 1000);

if flagIsBig
  %Do big code
else %not flagIsBig
  %Do not big code
end

This takes more characters, but is very readable. I think only community voting can clear this up. What do you think?

-Doug

Nice solution, but it call pdist twice unnecessarily. If you wish to reduce the length of code, the following is shorter but also more readable:

d = pdist([x;y]');
[i,j] = find(squareform(d)==min(d),1,'first');

The length of code can be checked as follows:

t = mtree('[i,j]=find(squareform(pdist([x; y]''))==min(pdist([x; y]'')),1,''first'')')

which gives 33 nodes.

t = mtree('d=pdist([x; y]'');[i,j]=find(squareform(d)==min(d),1,''first'')')

only 28 nodes.

hth
Yi

n = 10;
x = rand(1,n);
y = rand(1,n);
allDist = pdist([x;y]');
[minDist,minLoc] = min(allDist);
[loc1,loc2] = find(tril(ones(n),-1));
minLoc1 = loc1(minLoc);
minLoc2 = loc2(minLoc);

Alternatively, we can use bsxfun to build up the distance map.

z = x + i*y;
distMap = tril(abs(bsxfun(@minus,z,z.')));
distMap(~distMap) = Inf;
[minCol,rowLoc] = min(distMap);
[minDist,colLoc] = min(minCol);
rowLoc = rowLoc(colLoc);

@Oliver: As a best practice, I will post my solution as the first comment so it is accessible.

Doug

I haven’t used meshgrid or surf before so I’m learning something new. I must be missing something since it seems like meshgrid was written to address a limitation of the syntax option of surf(X, Y, Z) when X & Y are arrays. I’m having trouble thinking of why anyone would choose to make X & Y arrays instead of vectors.

The video worked very well to talk me thru the example and you did a very fine job of recording & editing a very understandable lesson. The only negative is that after I finished the video, I went to read the FRPs for meshgrid & surf, but I didn’t have your code to reference since the video had ended & reset.

dist=sqrt(bsxfun(@minus,x,x').^2+bsxfun(@minus,y,y').^2);
dist(dist==0)=10;       % Cancel the main diag
[i,j]=find(dist==min(dist(:)))
plot(x,y,'.',x(i),y(i),'o')

http://en.wikipedia.org/wiki/Closest_pair_of_points

:-)

<pre><code>

code goes here.

</pre></code>

[edit by Doug to have both <pre> and <code> tags in suggestion. Also edited old comment to do this.