import math __author__ denis f_global lambda _x math exp _x a_global b

  • Anonymous
  • NA
  • 05 May 2014 
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import math



__author__ = 'denis'



f_global = lambda _x: math.exp(_x)

a_global = 0

b_global = 3

phi = (1 + math.sqrt(5)) / 2

e = 0.00000001





def find_min_gold(f, a, b):

    while math.fabs(b - a) > e:

        x1 = b - (b - a) / phi

        x2 = a + (b - a) / phi

        y1 = f(x1)

        y2 = f(x2)

        if y1 >= y2:

            a = x1

        else:

            b = x2

    return (a + b) / 2





def find_min_half(f, a, b):

    while (math.fabs(b - a)) > e:

        half_x1 = ((a + b) / 2 - e/4)

        half_x2 = ((a + b) / 2 + e/4)

        if f(half_x1) <= f(half_x2):

            b = half_x2

        else:

            a = half_x1

    return (a + b) / 2





minimum1 = find_min_gold(f_global, a_global, b_global)

minimum2 = find_min_half(f_global, a_global, b_global)

print('Minimum of function on [' + str(a_global) + ', ' + str(b_global) + '] is ' + str(f_global(minimum1)) + '')

print('Minimum of function on [' + str(a_global) + ', ' + str(b_global) + '] is ' + str(f_global(minimum2)))
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