(cos (scale-float 1d0 120)) incorrect
Raymond Toy <[email protected]>
| Newsgroups | gmane.lisp.clisp.devel |
|---|---|
| Message-ID | <[email protected]> |
Clisp 2.49 on a Linux Ubuntu box says: [1]> (cos (scale-float 1d0 120)) 1.0d0 The true answer is closer to -0.92. Cmucl and ccl produce this answer. Maxima says this is the correct answer. I think the issue is that pi reduction is not done to full precision. Using long-floats, clisp still produces 1L0, but making long-float-digits 128 gives the correct answer. Note also that (scale-float 1d0 120) can be represented exactly as an IEEE754 double precision value, and that IEEE754 doubles are not approximations. They are exact rationals (of a certain form). Ray ------------------------------------------------------------------------------ Shape the Mobile Experience: Free Subscription Software experts and developers: Be at the forefront of tech innovation. Intel(R) Software Adrenaline delivers strategic insight and game-changing conversations that shape the rapidly evolving mobile landscape. Sign up now. http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk _______________________________________________ clisp-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/clisp-devel