I am trying to create a simple 2d plot by solving a equation in x and y,
for given y.
I am using sympy.mpmath.findroot to solve the equation. It solves it
correctly for all 'y' points, except for a few ones, where the 'x' I get on
solving starts diverging (giving no solution if I take points even more
finely). I have also attached the associated plot. What I expect is a
simple quadratic plot, for all 'y' points (from 0 to ).
This is the code -
#################################################################
from numpy import arange
from sympy import *
import matplotlib.pyplot as plt
p,q,r = -0.000116108381457823, 0.180075602770215, 12.0188009030456
Y_ = arange(0,1,0.01)
X = []
Y = []
x = symbols('x')
for y in Y_:
def f1(x):
y0 = ( -(x - y/2 + q/2 - p) + sqrt((x - y/2 + q/2 - p)**2 - \
4.60844*(p*y-x*q)*(y-q)) )/(2.30422*(y-q))
return (y0 - y)
try:
X.append(mpmath.findroot(f1, 0, verbose=False, tol=1e-3, verify=True))
Y.append(y)
except ValueError:
print '.',
plt.plot(X, Y)
plt.show()
#################################################################
<https://lh4.googleusercontent.com/-nJYWoNYqwpM/UX-NBTejvgI/AAAAAAAADEA/s-JJjlsMHTE/s1600/sympy_mpmath_findroot.png>
Kindly help me finding what is wrong here. (Note, I need to get 10 such
plots).
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