Hello, gretl users, It is possible to the asymmetric effects using waldTest.gfn . When I apply the following code (from previous tags) to apply my programme ,I got the following message: "A function definition must have a return type and name" The code: function restr (matrix *b) matrix ret = b[3]/b[2] - b[4]/b[2] return matrix ret end function open data4-10 ols 1 0 2 3 4 5 restrict rfunc = restr end restrict Can you any one help and suggest the code ( or) function to test the above restriction? Best regards, Dhanasekaran K