On Fri, Jun 26, 2009 at 6:54 AM, <kgotlele...@galmail.co.za> 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 > > 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' > >
You might want to have a look at scipy.optimize <http://docs.scipy.org/scipy/docs/scipy-docs/optimize.rst/#optimize> If you have more (somewhat) SciPy related questions, you might want to ask them on the SciPy mailing list. It's very active. <http://scipy.org/Mailing_Lists> Cheers, Skipper _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
