gnuplot-info

[Gnuplot-info] calculation/potentiation errors

[S <ste...@gm...>]

Hello,

I am trying to produce plots on very broad ranges of numbers (as broad
as between 1e20 and 1e-10). I have discovered, that when I try to
calculate e.g.
10**-14
the result is somewhere at 1e9. These miscalculations make my plots
incorrect.

Minmal command to reproduce the problem:
   print 10**-14
the result is
   3.61732686836958e-09
when it should return 1.0e-14 .

Is there a way to solve this or a workaround? Why is this so?

Thanks,

Stephan

Re: [Gnuplot-info] calculation/potentiation errors

[Lars H. <la...@ho...>]

> I am trying to produce plots on very broad ranges of
> numbers (as broad as between 1e20 and 1e-10). I have
> discovered, that when I try to calculate e.g.
> 10**-14
> the result is somewhere at 1e9. These miscalculations
> make my plots incorrect.
>
> Minmal command to reproduce the problem:
>    print 10**-14
> the result is
>    3.61732686836958e-09
> when it should return 1.0e-14 .
>
> Is there a way to solve this or a workaround? Why is this
> so?

Hi Stephan,
gnuplot knows two different types of numbers, real and 
integer. See help expressions for more details. Your error 
occurs, when you use integers instead of real numbers. Try 
this:
print 10**-14
  3.61732686836958e-09
print 10**14.0
  1e-14

HTH
Lars