[Maxima] roundoff errors

[Raymond Toy]

Uwe Weber wrote:
> Hello,
>
> I recently abused Maxima 5.16.3 as a pocket calculator and noticed that 
> it produced strange roundoff errors in simple floating point 
> multiplications:
>
> wxMaxima 0.7.6 http://wxmaxima.sourceforge.net
> Maxima 5.16.3 http://maxima.sourceforge.net
> Using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (aka GCL)
>
> (%i1) 325.65+471.67;
> (%o1) 797.3199999999999
>
> (%i2) 17.91+34.77;
> (%o2) 52.68000000000001
>
>   
Expected behavior with floating point numbers.  The numbers you give do
not have floating point values so they are rounded to the nearest
representable value.  Use rationals if you want exact answers.

Ray