How to clear "last warning"?

Hi!

SHORT QUESTION: I would like to clear the value "lastwarn" in a nice way so that I can create loops.

BACKGROUND: I want to count the number of warnings " Matrix is singular to working precision." that Matlab generates. I have read http://www.mathworks.com/matlabcentral/answers/32348-using-if-warning-as-a-conditional-statement But it does not say how to clear the last warning. Currently I am creating a new warning for this purpose (see the following code). Does anybody know a better solution?

vector_input=[0 1 0]';
vector_output= -100*ones(size(vector_input));
number_warnings=0;

for k=1:size(vector_input,1)
%      warning on MATLAB:nearlySingularMatrix;
    vector_output(k)=inv( vector_input(k));
    [msglast, msgidlast] = lastwarn;
   if strcmp(msgidlast,'MATLAB:singularMatrix')
        number_warnings=number_warnings+1;
    end
    s = warning('off','all'); % turn display of all warnings off
    warning('FineId','fine') % becomes the last warning
    warning(s) % turn display of all warnings on
end

Answer 1

[Honglei Chen]

warning('')

[Benjamin]

Thanks a lot Honglei Chen! I have just adapted your answer to the following

lastwarn('')

[Walter Roberson]

Turns out to require lastwarn('') now.