Kgotlelelo Legodi wrote:
Hi,
I am trying to write a program in python that solves a system of
nonlinear equations using newton's method. I don't know what I am
doing wrong. Please help
Mostly what you are "doing wrong" is failing to tell us why you think
there is a problem! What results are you expecting and what are you getting?
from scipy import*
x = array([0.0,0.0,0.0])
n=len(x)
tol= 0.00001
N=30
k=1
while k <= N:
def f(x):
f= zeros((len(x)),float)
f[0][k]= x[0][k]**2 + x[1][k]-37
f[1][k]=x[0][k]- x[1][k]**2- 5
f[2][k]= x[0][k] + x[1][k]+ x[2][k]- 3
return f[k]
def J(x):
J= zeros((n,n),float)
for i in range(n):
ei=zeros(n,float)
ei[i]=1.0
J[:i]=(f(x[k]+tol*ei)-f(x[k]))/tol
return J
y[k] = -(J.I)*f[k]
x[k+1]=x[k]+y[k]
if sqrt(dot(f0,f0)/len(x)) < tol: print x
else:
k=k+1
print 'Too many iterations'
--
Bob Gailer
Chapel Hill NC
919-636-4239
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
