Hi, simple script: <script> set echo off set messages off function void FOO (matrix mat) printf "%d\n", nelem(mat) end function nulldata 10 matrix foo = zeros(2,1) FOO(foo) foo[1,1] = 1 FOO(foo) </script> In both situations we get what we excpect: 2 But edit matrix 'foo' in "gretl: icon view" and then run FOO(foo)... oups, this is what I get: ---------------- ? FOO(foo) Variable number 2 is out of bounds *** error in function FOO Error executing script: halting ---------------- -- Marcin Błażejowski http://www.wrzosy.nsb.pl/~marcin/ GG# 203127