idamnjanovic@1: function id = diag_ids(x,k)
idamnjanovic@1: %DIAG_IDS Indices of matrix diagonal elements.
idamnjanovic@1: %  ID = DIAG_IDS(X) returns the indices of the main diagonal of X.
idamnjanovic@1: %
idamnjanovic@1: %  ID = DIAG_IDS(X,K) returns the indices of the K-th diagonal. K=0
idamnjanovic@1: %  represents the main diagonal, positive values are above the main
idamnjanovic@1: %  diagonal and negative values are below the main diagonal.
idamnjanovic@1: 
idamnjanovic@1: 
idamnjanovic@1: %  Ron Rubinstein
idamnjanovic@1: %  Computer Science Department
idamnjanovic@1: %  Technion, Haifa 32000 Israel
idamnjanovic@1: %  ronrubin@cs
idamnjanovic@1: %
idamnjanovic@1: %  September 2006
idamnjanovic@1: 
idamnjanovic@1: 
idamnjanovic@1: if (nargin==1), k=0; end
idamnjanovic@1: 
idamnjanovic@1: [m,n] = size(x);
idamnjanovic@1: l = max(m,n);
idamnjanovic@1: 
idamnjanovic@1: if (k<=0)
idamnjanovic@1:   id = (0:l-1)*m + (1:l) - k;
idamnjanovic@1: else
idamnjanovic@1:   id = (0:l-1)*m + (1:l) + k*m;
idamnjanovic@1: end
idamnjanovic@1: 
idamnjanovic@1: if (l-k>m), id = id(1:end-(l-k-m)); end
idamnjanovic@1: if (l+k>n), id = id(1:end-(l+k-n)); end