Re: Bug in fixed_point?!
On 12/20/10 10:03 PM, C Barrington-Leigh wrote: I cannot figure out what I'm doing wrong. The following does not return a fixed point: from scipy import optimize xxroot= optimize.fixed_point(lambda xx: exp(-2.0*xx)/2.0, 1.0, args=(), xtol=1e-12, maxiter=500) print ' %f solves fixed point, ie f(%f)=%f ?'% (xxroot,xxroot,exp(-2.0*xxroot)/2.0) You will want to ask scipy questions on the scipy-user mailing list: http://www.scipy.org/Mailing_Lists When you do, please provide the information that Terry Reedy asked for. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Bug in fixed_point?!
On Dec 21, 9:36 am, Robert Kern robert.k...@gmail.com wrote: When you do, please provide the information that Terry Reedy asked for. Sorry; quite right. For completeness I'll post here as well as over on scipy. Here's the actual code: - from scipy import optimize from math import exp xxroot= optimize.fixed_point(lambda xx: exp(-2.0*xx)/2.0, 1.0, args=(), xtol=1e-12, maxiter=500) print ' %f solves fixed point, ie f(%f)=%f ?'% (xxroot,xxroot,exp(-2.0*xxroot)/2.0) Here is the output -- Python 2.6.6 (r266:84292, Sep 15 2010, 16:22:56) In [1]: run tmp.py 0.332058 solves fixed point, ie f(0.332058)=0.257364 ? -- http://mail.python.org/mailman/listinfo/python-list
Re: Bug in fixed_point?!
On 12/20/2010 10:03 PM, C Barrington-Leigh wrote: I cannot figure out what I'm doing wrong. The following does not return a fixed point: What did it do? For nearly all such questions, cut and paste actual output or traceback. from scipy import optimize xxroot= optimize.fixed_point(lambda xx: exp(-2.0*xx)/2.0, 1.0, args=(), xtol=1e-12, maxiter=500) print ' %f solves fixed point, ie f(%f)=%f ?'% (xxroot,xxroot,exp(-2.0*xxroot)/2.0) from math import exp x = 1.0 for i in range(70): print(repr(x)) x = exp(-2.0*x)/2.0 converges to 0.2835716452048919 Did you cut and paste what you actually ran? -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
