# [Tutor] Vpython

Jacob S. keridee at jayco.net
Sun Dec 19 01:21:41 CET 2004

```> > I was wondering were can I find some Vpython graphics program codes that

I have 2 that I am proud of.

A simple function grapher
Usage:
>0.125*x**2

Graphs y = 1/8*x**2

>y = 1/x

Graphs y = 1/x

>clear

Clears display window

>r = t**2

Graphs polar function r = t**2

>remove lines

Removes all axes, including polar axes, should a polar function be graphed
after

>return lines

Returns all lines, so that they appear when appropriate.

>x = sin(x**2)+log(x**2)

Graphs the function...

------------------------------------------------------

from __future__ import division
from visual import *
import os
from math import *
ja = 0

def start():
for objects in scene.objects:
objects.visible = 0
scene.title = "Function Grapher by Jacob, Inc."
tem = raw_input('Are you on a desktop, or a notebook? ')
if tem == 'desktop':
scene.x = 365
if tem == 'notebook':
scene.x = 574
scene.visible=1
scene.exit=0
scene.userspin = 0
scene.range=(10,10,1)
scene.background=(1,1,1)
global xaxis
global yaxis
xaxis = curve(color=color.black)
xaxis.append(pos=(100,0,0))
xaxis.append(pos=(-100,0,0))
yaxis = curve(color=color.black)
yaxis.append(pos=(0,100,0))
yaxis.append(pos=(0,-100,0))

start()
y = 3
m = 0
t = 0
d = 1
print """\
List of Commands:
clear
quit
remove lines
return lines

Function Syntax:
var = funct a,b
where var = what
and funct = f(what)
and a,b = range
"""

print 'Please type in functions in below. '
while y != "":
lists=[]
y = raw_input('>')
if y == 'clear':
scene.visible=0
start()
print "-"*36
continue
elif y == 'quit':
scene.visible = 0
del scene
break
elif y == 'remove lines':
for x in a:
x.visible = 0
d = 0
continue
elif y == 'return lines':
for x in a:
x.visible = 1
d = 1
continue
if y.count('=') == 1:
y = y.split(' = ')
type = y[0].lower()
y = y[1]
y = y.replace("y","x")
if type == 'r':
y = y.replace('x','t')
if d == 1:
else:
type = 'y'
y = y.split(" ")
if len(y) > 1:
pass
else:
if type == 'r':
y.append('0,5*pi')
else:
y.append('-10,10')
range = y[1]
y = y[0]
range = range.split(",")
min = float(eval(range[0]))
max = float(eval(range[1]))
lists.append(curve(color=(1,0,1)))
x = min
if type == 'y' or type == 'x':
while x >= min and x <= max:
x = x+0.005
try:
if eval(y) <= 15 and eval(y) >= -15:
if type == 'y':
lists[-1].append(pos=(x,eval(y),0))
elif type == 'x':
lists[-1].append(pos=(eval(y),x,0))
else:
lists.append(curve(color=(1,0,1)))
except:
pass
elif type == 'r':
m = 'eval(y)*cos(t)'
n = 'eval(y)*sin(t)'
t = min
while t >= min and t <= max:
try:
lists[-1].append(pos=(eval(m),eval(n),0))
except:
lists.append(curve(color=(1,0,1)))
t = t+0.005

```