Dear developers, This morning I compiled gretl from CVS and found a typo in the hansl primer, section 4.2: Matrix Operations. Oddly enough, the matrix called *pina* does not produce en error since matrix *a* is 2×2, c=a' is 2×2, and pina=c+a can be generated from conformable matrices. Maybe you should change it to pina=b+c in order to demonstrate the non-conformability of a sum? -- Yours sincerely, | С уважением, Andreï V. Kostyrka. | Андрей Викторович Костырка. http://kostyrka.ru, http://kostyrka.ru/blog