# 1 Matlab Error and Warning Handling

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## 1.1 Turn off Warning Messages

During estimation, at some parameter values, estimation routine generates warnings messages. These warning messages fill up the screen and makes it hard to track estimation outputs. In the example below, we run an OLS regression that generates a warning message. We turn the message off, and then we turn the message on again.

First run a regression that generates a warning message.

% OLS Regression
fci_ols_lin = @(y, x) (x'*x)^(-1)*(x'*y);
% Regression inputs
ar_y = [1;1];
mt_x = [0 0; 0 0];
% Estimates
ar_esti = fci_ols_lin(ar_y, mt_x);

Warning: Matrix is singular to working precision.

Second, identify and turn off the warning message.

% Check warning message and warning ID of the last message.
[st_msg, st_warnID] = lastwarn;
% Turn off earning message
warning('off', st_warnID);
% Estimates no longer generates warning
ar_esti = fci_ols_lin(ar_y, mt_x);

Third, turn warning message back on.

% Warning message back on
warning('on', st_warnID);
% Estimates generates warning again
ar_esti = fci_ols_lin(ar_y, mt_x);

Warning: Matrix is singular to working precision.