Re: float to integer conversion anomalies

[Rob Mahurin]

On Jun 30, 2009, at 5:16 AM, Levente Torok wrote:
> Hi All,
>
> May be I am commenting something that has already been reported or  
> even solved.
> On octave-3.0.5 I found a somewhat inconsistent behavior.
>
> octave:2> for i=.1:.1:2
> > i*10
> > endfor
> ans =  1
> ans =  2
> ans =  3.00000000000000  <-????

This is because 0.3 does not have an exact floating-point  
representation:
octave:2> sprintf("%.19f",.3)
ans = 0.2999999999999999889

> Which is not a problem as long as I don't want to index with this.  
> But if I do I got error message.
>
> octave:3> for i=.1:.1:2
> > z(i*10)=1;
> > endfor
> error: expecting integer index, found 3.000000
> error: assignment failed, or no method for `matrix = scalar'
> error: evaluating assignment expression near line 4, column 8
> error: evaluating for command near line 3, column 1

Try z(round(i*10)).

Rob

--
Rob Mahurin
University of Manitoba, Dept. of Physics & Astronomy
at:     Oak Ridge National Laboratory   865 207 2594
        Oak Ridge, Tennessee            address@hidden