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27 lines
908 B
Python
27 lines
908 B
Python
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from linear_algebra_utils import LinearAlgebraUtils
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class EigenvalueMethods:
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@staticmethod
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def power_method(A, max_iter=1000, tol=1e-6):
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n = len(A)
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x = [1] * n
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lambda_old = 0
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for _ in range(max_iter):
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x = LinearAlgebraUtils.matrix_vector_multiply(A, x)
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lambda_new = LinearAlgebraUtils.vector_norm(x)
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x = LinearAlgebraUtils.scalar_divide(x, lambda_new)
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if abs(lambda_new - lambda_old) < tol:
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break
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lambda_old = lambda_new
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return lambda_new
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@staticmethod
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def inverse_power_method(A, max_iter=1000, tol=1e-6):
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n = len(A)
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I = [[1 if i == j else 0 for j in range(n)] for i in range(n)]
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A_inv = [[I[i][j] - A[i][j] for j in range(n)] for i in range(n)]
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return 1 / EigenvalueMethods.power_method(A_inv, max_iter, tol)
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