Hi again, and thanx for your quick responses ! I finally used something heavier, that does it also: matrix Z=zeros[4,4] matrix Z[1,]=transp(logement.$coeff[2:5]) matrix Z[2,]=transp(transport.$coeff[2:5]) matrix Z[3,]=transp(composite.$coeff[2:5]) ([2:5] because i drop the constant) well, I will append with your advice using matrix concatenation. Just to, add, I am using the script mode under windows XP, excuted in english from the XP console. However, I can run the script only once, then, if I modify it and rerun, gretl crashes. So I must launch gretl every time. Do you have an idea about some parameter to set inside windows ? thanx again and see ya Franck