Re: [Gnuplot-bugs] bug in division

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

the problem is 'integer division':

V=2
L=20
print V/L
V=2.
print V/L


Philipp Krüger-2 wrote:
> 
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> Hello!
> 
> I just downloaded gnuplot 4.4 patchlevel 2 and am having the following
> weird problem: I have two variables V=2 and L=20 and if I try to divide
> V by L, the result is 0. I had to pick the whole script apart until I
> found it - the desired outcome of this command is of course the output
> 0.1.
> 
> Here is the script:
> #######
> set terminal png transparent size 1200,800 enhanced
> set xtics 0.1
> set grid xtics ytics mxtics mytics
> set output 'U_vs_s.png'
> set key left top
> set key box linestyle 1
> set xlabel 's'
> set ylabel 'U(s)'
> 
> # Halfwidth of strip in m
> a=2
> # Strip width in m
> w=2*a
> # Strip thickness in m
> d=2e-3
> #Voltage in V
> V=2
> # Width of simulation box in m
> L=20
> # Speed of light in m/s
> c=2.99792458e8
> # Permeability constant
> mu0=4*pi*1e-7
> # Permittivity
> eps0=1/(mu0*(c**2))
> 
> # ANSYS fitting
> Kx=pi*(V/L)*eps0
> KCorrX=7.293e-3
> y1=(8*(c**2))
> y2=(w*d)
> y3=V/L # Here this strange error occurs
> set label 'y1=%10.5e',y1 at graph 0.01, graph 0.87
> set label 'y2=%10.5e',y2 at graph 0.01, graph 0.84
> set label 'y3=%10.5e',y3 at graph 0.01, graph 0.81
> # the former line outputs "y3=0.00000e+000"
> #Ky=y1/y2
> KCorrY=1.413
> 
> plot 'Uac.dat' using ($1):($3) title 'data' w p 1
> #######
> 
> Is this indeed a bug or am I doing something exceptionally stupid?
> 
> Thanks in advance for looking into the matter.
> 
> Kind regards,
> 
> P. Krüger
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