Hi Huy, On Sun, May 22, 2005 at 05:50:02AM -0700, Huy wrote: > Second, I found a weird bug when adding two float > numbers. Below is my transcript: > > --------------------- > [metis:/home/hpham]$ eclipse > ECLiPSe Constraint Logic Programming System [kernel] > Kernel and basic libraries copyright Cisco Technology > Inc > Academic licensing through Imperial College London, > see legal/licence_acad.txt > GMP library copyright Free Software Foundation, see > legal/lgpl.txt > For other libraries see their individual copyright > notices > Version 5.8 #78, Sat Jan 8 00:10 2005 > [eclipse 1]: +(-0.2, -2.7, X). > > X = -2.9000000000000004 > Yes (0.00s cpu) > [eclipse 2]: There is no bug here - this is floating point arithmetic. Try the same computation in C (or your other favourite language) and get it to print the result at *full* precision (i.e. enough precision to be sure that when you read it back in you'll get exactly the same floating point number). The lack of precision for floating point arithmetic is mentioned in passing in the User Manual -> Arithmetic Evaluation -> Numeric Types and Type Conversions, in the sections on Floating Point Numbers and Bounded Real Numbers - in passing because we generally assume users know about this. It is covered in a little more detail in the Tutorial, in Chapter 9, "Working with real numbers and variables." Cheers, WarwickReceived on Sun May 22 14:41:48 2005
This archive was generated by hypermail 2.1.8 : Wed 16 Nov 2005 06:07:36 PM GMT GMT