Ryan Krauss wrote:
I have run into this as well. 1e-16 seems large to me for double precision. Robert can you explain this a bit more please. Is there an IEEE spec or something that specifies how much of the 64bits is for exponent and how much is for the mantissa (I think that is the right word)? I was playing with some FORTRAN code and it seems like there was a big difference with complex vs. double complex. It seems like 1e-16 was the magnitude floor of complex and double complex was better.
IEEE-754 double precision has 11 bits for exponent, 1 bit for sign, and 52 for the rest of the mantissa. 2.**-52 ~= 2.22e-16 Goldberg, David. What Every Computer Scientist Should Know About Floating Point Arithmetic. 1991. http://www.physics.ohio-state.edu/~dws/grouplinks/floating_point_math.pdf -- Robert Kern robert.kern@gmail.com "In the fields of hell where the grass grows high Are the graves of dreams allowed to die." -- Richard Harter