Spring
This was originally written for python by Dima and Barry.
"""
modified for making a graph in Sage
bic 3/16/11
"""
def firstcross(krange):
"""
Returns first k where graph crosses axis
Returns 0 when never crosses axis
"""
statement = 1
for k in krange:
v=0.0
x=5.0
m=50.0
c=20.0
t=100
timestep = 0.01
for n in range(int(t/timestep)):
nextx = x+timestep*v
nextv = v+timestep*(-k/m*x-c/m*v)
xsign = abs(x)/x
nextxsign = abs(nextx)/nextx
x=nextx
v=nextv
if xsign != nextxsign:
if statement == 1:
statement = 0
return k
return 0
def doonek(k):
"""
returns a list of coordinates as a function of time
"""
v=0.0
times = []
coordinates = []
plot_data = []
x=5.0
m=50.0
c=20.0
t=160.0
timestep = 0.01
currenttime=0
for n in range(int(t/timestep)):
nextx = x+timestep*v
nextv = v+timestep*(-k/m*x-c/m*v)
xsign = abs(x)/x
nextxsign = abs(nextx)/nextx
times.append(currenttime)
currenttime += .005
coordinates.append(x)
x=nextx
v=nextv
springdata = [(times[n], coordinates[n]) for n in range(len(times))]
return springdata
"""
first range:
"""
def rangegenerator(cross, upper, increment):
arange = []
n=0
while n<=upper:
arange.append(cross-upper+n)
n=n+increment
return arange
def allranges(genrange, cross, upper, increment):
genrange = rangegenerator(cross, upper, increment)
cross = firstcross(genrange)
return cross
arange = []
brange = []
cross = 100
for i in range(2):
cross = allranges(arange, cross, 100, 1)
cross = allranges(arange, cross, 100, 1)
cross = allranges(arange, cross, 1, .01)
crange = rangegenerator(cross, .01, .0001)
k = firstcross(crange)
springData = doonek(k)
print "k=",k
k= 2.04470000000000 k= 2.04470000000000 |
list_plot(springData)
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