function ip_plus_diag(X,y)
% function ip_plus_diag(X,y)
%
% Example usage:
% 	ip_plus_diag('X','y');
% Does the same as:
% 	X=plus_diag(X,y);
% Or
% 	X=X+diag(y); % for vector y
%
% Should not be necessary, but older Matlabs don't do plus_diag in place.
% In theory it has enough information to know it could in this situation.
% Matlab R2007a onwards do do plus_diag in place when called from a function
% (not a script or the command-line).
%
% Inputs:
% 	 X string giving name of NxN variable in calling workspace
% 	 y string giving name of Nx1, 1xN or 1x1 variable...

% Iain Murray, June 2006, updated comments July 2008

evalin('caller',['diagidx=(0:size(',X,',1)-1)*size(',X,',1)',...
                 '+(1:size(',X,',1));',...
                 X,'(diagidx)=',X,'(diagidx)+',y,'(:)',39,';']);