Thank very good However, there is something that I do not understand I define W1=0.2 z(x) = (x + W1*{0,1}) w(x) = faddeeva (z (x)) and Voi (x) = voigt (x, W1) Voi (x) and real (w(x)) are exactly the same Now, d_w (x) = - 2 * z (x) * w (z (x)) + 2*{0,1}/sqrt(pi) " which is the derivative D_voi(x,del) = (Voi (x+del) - Voi (x-del)) / 2 / del now plot [-4:4] D_voi(x,0.001) and plot [-4:4] real (d_w (x)) are different except for W1=0 What am I doing wrong? It seems that the issue is with the faddeeva, or when I my calls! Thank. =========================================================================== Patrick DUPRÉ | | email: pdupre@xxxxxxx Laboratoire de Physico-Chimie de l'Atmosphère | | Université du Littoral-Côte d'Opale | | Tel. (33)-(0)3 28 23 76 12 | | Fax: 03 28 65 82 44 189A, avenue Maurice Schumann | | 59140 Dunkerque, France =========================================================================== _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx