diff Problems/private/diag_ids.m @ 10:207a6ae9a76f version1.0

(none)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Problems/private/diag_ids.m	Mon Mar 22 15:06:25 2010 +0000
@@ -0,0 +1,30 @@
+function id = diag_ids(x,k)
+%DIAG_IDS Indices of matrix diagonal elements.
+%  ID = DIAG_IDS(X) returns the indices of the main diagonal of X.
+%
+%  ID = DIAG_IDS(X,K) returns the indices of the K-th diagonal. K=0
+%  represents the main diagonal, positive values are above the main
+%  diagonal and negative values are below the main diagonal.
+
+
+%  Ron Rubinstein
+%  Computer Science Department
+%  Technion, Haifa 32000 Israel
+%  ronrubin@cs
+%
+%  September 2006
+
+
+if (nargin==1), k=0; end
+
+[m,n] = size(x);
+l = max(m,n);
+
+if (k<=0)
+  id = (0:l-1)*m + (1:l) - k;
+else
+  id = (0:l-1)*m + (1:l) + k*m;
+end
+
+if (l-k>m), id = id(1:end-(l-k-m)); end
+if (l+k>n), id = id(1:end-(l+k-n)); end