101 lines
3.1 KiB
Python
101 lines
3.1 KiB
Python
import numpy as np
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import tabulate as tb
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class Simplex:
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def __init__(self, source):
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m, n = source.shape
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self.table = np.zeros((m, n + m - 1))
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self.basis = []
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for i in range(m):
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for j in range(self.table.shape[1]):
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if j < n:
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self.table[i, j] = source[i, j]
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else:
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self.table[i, j] = 0
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if (n + i) < self.table.shape[1]:
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self.table[i, n + i] = 1
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self.basis.append(n + i)
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self.m = m
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self.n = self.table.shape[1]
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def calculate(self, result):
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counter = 0
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while not self.is_it_end() and counter < 10:
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main_col = self.find_main_col()
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main_row = self.find_main_row(main_col)
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self.basis[main_row] = main_col
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new_table = np.zeros((self.m, self.n))
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for j in range(self.n):
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new_table[main_row, j] = self.table[main_row, j] / self.table[main_row, main_col]
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for i in range(self.m):
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if i == main_row:
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continue
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for j in range(self.n):
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new_table[i, j] = self.table[i, j] - self.table[i, main_col] * new_table[main_row, j]
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self.table = new_table
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counter += 1
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print("Main col: " + str(main_col))
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print("Main row: " + str(main_row))
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print("Basis: ")
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for i in self.basis:
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print(self.basis.index(i), i)
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print(tb.tabulate(self.table))
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for i in range(len(result)):
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k = self.basis.index(i + 1) if i + 1 in self.basis else -1
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result[i] = self.table[k, 0] if k != -1 else 0
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return self.table
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def is_it_end(self):
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return np.all(self.table[self.m - 1, 1:] >= 0)
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def find_main_col(self):
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main_col = 1
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for j in range(2, self.n):
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if self.table[self.m - 1, j] > self.table[self.m - 1, main_col]:
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main_col = j
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return main_col
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def find_main_row(self, main_col):
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main_row = 0
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for i in range(self.m - 1):
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if self.table[i, main_col] > 0:
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main_row = i
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break
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for i in range(main_row + 1, self.m - 1):
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if self.table[i, main_col] > 0 and (self.table[i, 0] / self.table[i, main_col]) < (
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self.table[main_row, 0] / self.table[main_row, main_col]):
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main_row = i
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return main_row
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if __name__ == "__main__":
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table = np.array([[7, 1, 1, 1, -1, 1, 0],
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[2, 1, -1, 1, -1, 0, -1],
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[-5, 3, -1, -2, 2, 0, 0],
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[0, -1, 2, -3, 3, 0, 0]])
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result = np.zeros(6)
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S = Simplex(table)
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table_result = S.calculate(result)
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print("Resulting simplex table")
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print(tb.tabulate(table_result))
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print("\nResult:")
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print(f"X[max] = {result}")
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print(f"F[max] = {-1 * table_result[-1][0]:.2f}") |