Add distance_ fcn

distance_.m

@@ -0,0 +1,48 @@
+function h = distance_(x,y, dir)
+%DISTANCE_ Determine distances between locations
+%
+%   This function produces a matrix that describes the
+%   distances between two sets of locations.
+%
+%INPUT PARAMETERS
+%   x   - location coordinates for data set #1 [n1 x D]
+%   y   - location coordinates for data set #2 [n2 x D]
+%   dir - if given, specifies the component direction to use 
+%OUTPUT PARAMETERS
+%   h - distance between points in x from points in y [n1 x n2]
+%
+%EXAMPLE:
+%   x=[0,0; 5,0; 5,5]
+%   y=[1,1; 5,5]
+%   h = distance_(x,y)
+%RESULT:
+%    1.4142    7.0711
+%    4.1231    5.0000
+%    5.6569         0
+
+%EXTERNAL FUNCTIONS CALLED: none
+%REVISION HISTORY:
+%   pkk, 5/13/97
+%   tae, 6/26/98 (minor changes)
+%   jlm, 4/11/2017 (add component direction)
+
+if nargin < 3, dir = []; end
+
+[n1,D] = size(x);
+[n2,D2] = size(y);
+
+if D~=D2
+   error('ERROR in DISTANCE_: locations must have same number of dimensions (columns)')
+end
+h = zeros(n1,n2);
+
+if isempty(dir)
+    for id = 1:D
+       h = h + (x(:,id)*ones(1, n2)-ones(n1,1)*y(:,id)').^2;
+    end
+else
+    h = (x(:,dir)*ones(1, n2)-ones(n1,1)*y(:,dir)').^2;
+end
+h = sqrt(h);
+
+end