def calc_g(self,e):
if self.data.points == []:
return
x = self.lentext.get()
try:
L = float(x)
except:
self.msgwin.msg('Set the length of the rod', 'red')
return
import phmath, math
dat = []
for k in self.data.points:
dat.append([k[0], k[1]])
res = phmath.fit_dsine(dat)
fit = []
exp = []
for k in res[0]:
fit.append([k[0],k[2]])
exp.append([k[0],k[3]])
self.data.traces.append(fit)
self.col = self.data.get_col()
self.plot2d.line(fit, self.col)
self.col = self.data.get_col()
self.plot2d.line(exp, self.col)
D = res[1][4]
T = 1.0 / res[1][1]
r = 0.14 # radius of the rod
R = 1.27 # radius of the ball
density = 7.8 # density of iron
m_rod = math.pi * r**2 * L * density
m_ball = math.pi * 4 / 3 * R**3 * density
# print m_rod,'',m_ball
Lprime = ( (m_rod * L**2)/3 + (m_ball * 2/5 * R**2) + m_ball * \
(L+R)**2 ) / ( (m_rod * L)/2 + m_ball*(L+R) )
g = 4.0 * math.pi**2 * Lprime / (T * T)
# print T, Lprime, g, D
ss = 'T = %4.3f seconds. Length = %4.2f | g = %4.0f \
cm/sec2 | Damping factor = %4.3f\n'%(T,L,g,D)
self.msgwin.showtext(ss)
import phm, phmath
p=phm.phm()
ifp=open('pend.dat','r')
data = []
while 1:
a = ifp.readline()
if len(a) < 3: break
ss = a.split()
data.append( [float(ss[0]), float(ss[1])])
res = phmath.fit_dsine(data)
frfit = res[1][1]*1.0e6
print frfit
p.plot(res[0])
p.save_data(res[0])
p.set_scale(0,-5,5,5)
raw_input()
