...variable = 1 -(sin(x)**2 + cos(x)**2) -|> where the answer should mathematically be zero, but is likely to -|> be off by a bit or two computationally. -|> -|> Dick Hendrickson -| -|yes I write varaible = 0. (double precision, real*8) Louis: I cannot reproduce your probllem in a trivial program. Suggest that you post your code or conjure up a small test case. Skip Knoble