gnuplot-beta

Parsing bug?

[Daniel <boy...@gm...>]

Hi folks,

I just tried plotting this equation,

T0 = 300
T1 = 6000
set xrange [T0:T1]
f(x) = (1 - x**4/T1**4) * (1 - T0/x)

Which should have two zeros at (x=300 and x=6000). It seems that because the numbers have been defined as integers it give the wrong result. Redefining,

T0 = 300.
T1 = 6000.

plots the correct function.

Is there a case for converting ints to floats as standard in the gnuplot interpreter? When using gnuplot as a user, I would expect the maths to just work without having to think about programming details like ints of floats. In a programming environment of course this is what I would expected.

Cheers,

Dan

Re: Parsing bug?

[Thomas S. <t.s...@fz...>]

this has been repaired in the development version of gnuplot:


        G N U P L O T
        Version 4.2 patchlevel 6 
gnuplot> print 6000**4
-2086600704


        G N U P L O T
        Version 4.4 patchlevel 0-rc1
gnuplot> print 6000**4
-2086600704


        G N U P L O T
        Version 4.5 patchlevel 0
gnuplot> print 6000**4
1.296e+15


Daniel Farrell wrote:
> 
> Hi folks,
> 
> I just tried plotting this equation,
> 
> T0 = 300
> T1 = 6000
> set xrange [T0:T1]
> f(x) = (1 - x**4/T1**4) * (1 - T0/x)
> 
> Which should have two zeros at (x=300 and x=6000). It seems that because
> the numbers have been defined as integers it give the wrong result.
> Redefining,
> 
> T0 = 300.
> T1 = 6000.
> 
> plots the correct function.
> 
> Is there a case for converting ints to floats as standard in the gnuplot
> interpreter? When using gnuplot as a user, I would expect the maths to
> just work without having to think about programming details like ints of
> floats. In a programming environment of course this is what I would
> expected.
> 
> Cheers,
> 
> Dan
> 
> 
> 
> ------------------------------------------------------------------------------
> The Planet: dedicated and managed hosting, cloud storage, colocation
> Stay online with enterprise data centers and the best network in the
> business
> Choose flexible plans and management services without long-term contracts
> Personal 24x7 support from experience hosting pros just a phone call away.
> http://p.sf.net/sfu/theplanet-com
> _______________________________________________
> gnuplot-beta mailing list
> gnu...@li...
> https://lists.sourceforge.net/lists/listinfo/gnuplot-beta
> 
> 

-- 
View this message in context: http://old.nabble.com/Parsing-bug--tp27514663p27521028.html
Sent from the Gnuplot - Dev mailing list archive at Nabble.com.

Re: Parsing bug?

[Ethan M. <merritt@u.washington.edu>]

On Tuesday 09 February 2010, Thomas Sefzick wrote:
> 
> this has been repaired in the development version of gnuplot:

>         G N U P L O T
>         Version 4.4 patchlevel 0-rc1
> gnuplot> print 6000**4
> -2086600704
> 
> 
>         G N U P L O T
>         Version 4.5 patchlevel 0
> gnuplot> print 6000**4
> 1.296e+15

Just to keep everyone on the same page...

The code base for the 4.4 was basically frozen at the time the
time the 4.4.0-rc1 snapshot was created.  Since then I've only
applied bug fixes, particularly for problems reported against -rc1.

I have kept a set of patches against 4.5 CVS to be applied to 
4.4 CVS once 4.4.0 is out the door.  So I expect these will appear
in 4.4.1:

   winmain_va_copy      Allows building with Visual C
   wxt_dashed           set term wxt ... {dashed|solid} {dashlength <dl>}
   x11_mousewheel		mousewheel support
   wxt_mousewheel		mousewheel support
   pow_overflow         if i**j would cause integer overflow, return a float instead
   int_overflow         Check internal integer multiplications for overflow
   tikz                 remove conditional tests for version 4.3
   candle_width         optional 6th column containing box width
   rmargin              tweak left and right margins to be more like those prior to 4.2.4
   jw-refactor          clean up the execute-from-string operations lf_push/lf_pop
   cc-for-build         fix for building documentation during cross-compilation
   percent_s            support the "%s" format specifier in strftime()
   Kalinin_metapost     Fix inheritance of line thickness by text strings
   suppress_PDFMark     rearrange postscript prolog to allow customization
   timefmt              handle evaluated input values for time format "%s"
   init_func_points     initialize full coordinate structure for 2D functions