48 lines
1.0 KiB
Python
48 lines
1.0 KiB
Python
import math
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def f_bisection(x):
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return x**3 - 6*x**2 + 11*x - 6
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def bisection_method(a, b, eps):
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fa = f_bisection(a)
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fb = f_bisection(b)
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if fa * fb > 0:
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raise ValueError("f(a)*f(b) > 0. No guarantee that a root exists in the interval [a,b].")
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while True:
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c = (a + b) / 2.0
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fc = f_bisection(c)
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if abs(fc) < eps:
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return c
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if fa * fc < 0:
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b = c
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fb = fc
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else:
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a = c
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fa = fc
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def f_golden(x):
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return (x - 2)**2 + 3
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def golden_section_search(a, b, eps):
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phi = (1 + math.sqrt(5)) / 2.0
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resphi = 2 - phi
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c = a + resphi * (b - a)
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d = b - resphi * (b - a)
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fc = f_golden(c)
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fd = f_golden(d)
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while (b - a) > eps:
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if fc < fd:
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b = d
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d = c
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fd = fc
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c = a + resphi * (b - a)
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fc = f_golden(c)
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else:
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a = c
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c = d
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fc = fd
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d = b - resphi * (b - a)
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fd = f_golden(d)
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