I have come across slightly strange and inconsistent behaviour in gretl. It is generated by the following script commands for a dataset that has been declared as a panel series panel_unit=$unit genr unitdum list dlist = du_* matrix dunit={dlist} matrix pnumb=sumc(dunit) print pnumb matrix dnumb=dunit*transp(pnumb) matrix dnper=sumr(dnumb) print dnper When I run this as a script it fails at the "matrix dunit={dlist}" because all of the dummy variables are missing or rather "NA" even though panel_unit has created correctly. However, when I use the Add/Unit dummies dialogue the dummy variables are valid with 1's and 0's in the correct places. Am I doing something wrong or is there a bug? This script is a rather cumbersome way of trying to get round the apparent lack of certain functions that would be very useful for handling panel data. These are: A. $period - give access to the period indicators within each panel unit, similar to $unit. B. pnumb(x) - returns a series contining the numbers of non-missing values for the series x for each panel unit (similar to pmean). C. pmax(x) - returns a series containing the maximum values of series x for each panel unit. D. pmin(x) - returns a series containing the minimum value of series x for each panel unit. As my example shows, it is possible to write external functions to perform the same tasks, but built-in functions would be much more efficient. Gordon