Gnuplot生成菲涅耳方程的怪异图

Question

我试图为菲涅尔系数生成图形，但图形是错误的。

#! /usr/bin/gnuplot -p

#Gnuplot script Fresnel equation
set term postscript eps enhanced color lw 2 "Arial" 20
set title "Fresnel do ar para vidro"
#set name for file
set output "fresnel.eps"
#Define refractive index middle 1
ni = 1
#Define refractive index middle 2
nt =  3/2
#Define constant
k = ni/nt
#Define conversion
TRAD = pi/180.0
#define cos, sin conversion
sind(x) = sin(x*TRAD)
cosd(x) = cos(x*TRAD)
#Define sqrt
sq(x) = sqrt( 1 - k**2 * sind(x)*sind(x) )
sqd(x) = sq(x*TRAD)
#R perpendicular
ri(x) = (ni*cosd(x) - nt*sqd(x)) / (ni*cosd(x) + nt * sqd(x))
#R paralelo
rii(x) = - (nt*cosd(x) - ni*sqd(x)) / (ni*sqd(x) + nt*cosd(x))
#Function
p(x) = (ri(x) - rii(x)) / (ri(x) + rii(x))

set ylabel "ress"
set xlabel "Angulo de incidencia"
set yrange [-1:2.5]
set autoscale x
#ploting graph
plot p(x), ri(x) with line, rii(x) w line

我需要得到一个类似于链接的图表：

https://www.geogebra.org/m/wKk62nUk

Answer 1

不是一个完整的解决方案，但有几点意见：

• nt = 3/2使用整数除法并产生nt = 1。您希望将nt = 1.5.
• The或nt = 3.0/2.0角度参数乘以TRAD。这是从度到弧度的转换。因此，应该将xrange设置为类似于set xrange [0:90]
• You sqd(x) = ...sq(x*TRAD)...、sq(x) = ...sind(x)...和sind(x) = sin(x*TRAD)的值。这个链会将初始参数乘以TRAD*TRAD。最有可能的是，您希望将sq(x) = ...sind(x)...更改为sq(x) = ...sin(x)...。

我们越来越接近所需的图形，但我们还没有完成。我想你应该再检查一下源方程。