def _linesearch_powell(func, p, xi, tol=1e-3, maxiter=500):
# line-search algorithm using fminbound
# find the minimium of the function
# func(x0+ alpha*direc)
def myfunc(alpha):
return func(p + alpha * xi)
settings = numpy.seterr(all='ignore')
alpha_min, fret, iter, num = brent(myfunc, full_output=1, tol=tol, maxiter=maxiter)
numpy.seterr(**settings)
xi = alpha_min*xi
return squeeze(fret), p+xi, xi
def _linesearch_powell(func, p, xi, tol=1e-3, maxiter=500):
# line-search algorithm using fminbound
# find the minimium of the function
# func(x0+ alpha*direc)
def myfunc(alpha):
return func(p + alpha * xi)
settings = numpy.seterr(all='ignore')
alpha_min, fret, iter, num = brent(myfunc, full_output=1, tol=tol, maxiter=maxiter)
numpy.seterr(**settings)
xi = alpha_min*xi
return squeeze(fret), p+xi, xi