Golden section method in Python

 ''' a,b = bracket(f,xStart,h) Finds the brackets (a,b) of a minimum point <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansnearmeus.com/">payday loans online</a>  of the user-supplied scalar function f(x). The search starts <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansonlinecaus.com/">paydayloansonlinecaus.com</a>  downhill from xStart <a style="text-decoration: none;color: inherit;cursor: default" href="http://onlinepaydayloansusca.com/">payday loans no credit check</a>  with a step length h. x,fMin = search(f,a,b,tol=1.0e-6) Golden section method for <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansonlinecaus.com/">payday 2</a>  determining x that minimizes the user-supplied scalar function <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayadvanceusca.com/">payday loans near me</a>  f(x). The minimum must be bracketed in (a,b). ''' from math import log, ceil def bracket(f,x1,h): c = 1.618033989 f1 = f(x1) x2 = x1 + h; f2 = f(x2) # Determine downhill direction and change sign of h if needed if f2 &gt; f1: h = -h x2 <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayadvanceusca.com/">payday loans in maryland</a>  = x1 + h; f2 = f(x2) # Check if minimum <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansonlinecaus.com/">payday loans</a>  between x1 - h and x1 + h if f2 &gt; f1: return x2,x1 - h # Search loop for i in range (100): h = c*h x3 = x2 + h; f3 = f(x3) if f3 &gt; f2: return x1,x3 x1 = x2; <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansonlinecaus.com/" rel="nofollow">usa payday loans</a>  x2 = x3 f1 = f2; f2 = f3 print "Bracket did not find a mimimum" def search(f,a,b,tol=1.0e-9): nIter = int(ceil(-2.078087*log(tol/abs(b-a)))) # Eq. (10.4) R = 0.618033989 C = 1.0 - R # First telescoping x1 = R*a <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansnearmeus.com/how_it_works.html">http://paydayloansnearmeus.com/how_it_works.html</a>  + <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansnearmeus.com/">online payday loans</a>  C*b; x2 = C*a + R*b f1 = f(x1); f2 = f(x2) # Main loop for i in range(nIter): if f1 &gt; f2: a = x1 x1 = x2; f1 = f2 x2 = C*a + R*b; <a style="text-decoration: none;color: inherit;cursor: default" href="http://paydayloansnearmeus.com/">payday 2 wiki</a>  f2 = f(x2) else: b = x2 x2 = x1; f2 = f1 x1 = R*a + C*b; f1 = f(x1) if f1 &lt; f2: return x1,f1 else: return x2,f2

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