This is very confusing



Am 8 Sep 2008 um 12:54 hat Richard Hennessy geschrieben:

> Try
> 
> (%i1) b:"a";
> (%o1) a
> (%i2) a:2;
> (%o2) 2
> (%i3) cos(b),numer;
> (%o3) cos(a)
> (%i4) remvalue(a,b);
> (%o4) [a,b]
> (%i5) b:a;
> (%o5) a(%i6) a:2;
> (%o6) 2
> (%i7) cos(b),numer;
> (%o7) -0.41614683654714
> 
> So (%o3) = cos(a) whereas (%o7) is a float.  This does not seems consistent to me.

Rich, this is absolutely consistent. Perhaps stringdisp:true makes it clear:

(%i1) stringdisp:true;
(%o1)                                true
(%i2) b:"a";
(%o2)                                 "a"
(%i3) a:2;
(%o3)                                  2
(%i4) cos(b),numer;
(%o4)                              cos("a")

numer has no effect on strings.

(%i5) remvalue(a,b);
(%o5)                               [a, b]
(%i6) b:a;
(%o6)                                  a
(%i7) a:2;
(%o7)                                  2
(%i8) cos(b),numer;
(%o8)                         - 0.41614683654714

numer causes an additional evaluation of cos(b). See ? numer

(%i9) cos(b);
(%o9)                               cos(a)

HTH
Volker


> Rich 
> 
> 
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