Files
Transportation_Problem/main.py
T

456 lines
13 KiB
Python

import numpy as np
from typing import Optional
from enum import Enum
# M constant
M = 1_000_000
class State(Enum):
SOLVED = 0
UNAPPLICABLE = 2
class Result:
solved: State
objective_function_value: Optional[np.int64]
solution: Optional[np.array]
def __init__(self,
solved: State,
objective_function_value: Optional[np.array] = None,
solution: np.int64 = None):
self.solved = solved
self.objective_function_value = objective_function_value
self.solution = solution
def NorthwestCorner(S: np.array,
C: np.array,
D: np.array) -> Result:
num_rows, num_cols = len(S), len(D)
solution = np.zeros((num_rows, num_cols), dtype=np.int64)
i, j = 0, 0
while i < num_rows and j < num_cols:
quantity = min(S[i], D[j])
solution[i][j] = quantity
S[i] -= quantity
D[j] -= quantity
if S[i] == 0:
i += 1
elif D[j] == 0:
j += 1
if sum(S) == 0 and sum(D) == 0:
objective_function_value = np.sum(solution * C)
return Result(State.SOLVED, objective_function_value, solution)
else:
return Result(State.UNAPPLICABLE)
#SAMPLE INPUT FOR TESTING
S = np.array([50, 60, 50, 50])
C = np.array([
[16, 16, 13, 22, 17],
[14, 14, 13, 19, 15],
[19, 19, 20, 23, M ],
[M, 0, M, 0, 0]])
D = np.array([30, 20, 70, 30, 60])
def Vogel(
S: np.array,
C: np.array,
D: np.array) -> Result:
iteration = 0
C_initial = C
C_init_height = len(C)
C_init_length = len(C[0])
solution_matrix = np.zeros((C_init_height, C_init_length), dtype=np.int64)
print(solution_matrix)
def add_to_solutions(val, x, y):
for yi in range(C_init_height):
for xi in range(C_init_length):
if (yi == y and xi == x):
solution_matrix[y][x] = val
C_numerated = np.zeros((C_init_height, C_init_length), dtype=np.int64)
C_numerated = np.insert(C_numerated, 0, [str(i+1) for i in range( C_init_length)], axis=0)
C_numerated = np.insert(C_numerated, 0, [str(i) for i in range( C_init_height+1)], axis=1)
print(C_numerated)
while (len(C[0]) > 1 and len(C) > 1):
iteration += 1
C_map = dict()
for y in range(len(C)):
for x in range(len(C[0])):
C_map[x, y] = C[y][x]
C_length = len(C[0])
C_height = len(C)
RowD = np.array
ColD = np.array
RowD = np.resize(RowD, C_height)
ColD = np.resize(ColD, C_length)
# Finding differences
for y in range(C_height):
RowD[y] = abs(sorted(C[y])[0] - sorted(C[y])[1])
for x in range(C_length):
ColD[x] = abs(sorted(C.T[x])[0] - sorted(C.T[x])[1])
# Maximum difference
maxD = max(np.concatenate((ColD, RowD)))
target_array = None
target_number = None
row_index_to_eleminate = None
column_index_to_eleminate = None
x_num = None
y_num = None
if maxD in RowD:
y = np.where(RowD == maxD)[0][0]
target_array = C[np.where(RowD == maxD)[0]][0]
target_number = min(target_array)
x = np.where(target_array == target_number)[0][0]
x_num = C_numerated[0][x+1]
y_num = C_numerated[y+1][0]
if (D[x] >= S[y]):
row_index_to_eleminate = y
selected_value = S[y]
D[x] -= selected_value
C = np.delete(C, row_index_to_eleminate, 0)
S = np.delete(S, row_index_to_eleminate, 0)
C_numerated = np.delete(C_numerated, row_index_to_eleminate+1, 0)
else:
column_index_to_eleminate = x
selected_value = D[x]
S[y] -= selected_value
C = np.delete(C, column_index_to_eleminate, 1)
D = np.delete(D, column_index_to_eleminate, 0)
C_numerated = np.delete(C_numerated, column_index_to_eleminate+1, 1)
if maxD in ColD:
x = np.where(ColD == maxD)[0][0]
target_array = C.T[np.where(ColD == maxD)[0]][0]
target_number = min(target_array)
y = np.where(target_array == target_number)[0][0]
x_num = C_numerated[0][x+1]
y_num = C_numerated[y+1][0]
if (D[x] >= S[y]):
row_index_to_eleminate = y
selected_value = S[y]
D[x] -= selected_value
C = np.delete(C, row_index_to_eleminate, 0)
S = np.delete(S, row_index_to_eleminate, 0)
C_numerated = np.delete(C_numerated, row_index_to_eleminate+1, 0)
else:
column_index_to_eleminate = x
selected_value = D[x]
S[y] -= selected_value
C = np.delete(C, column_index_to_eleminate, 1)
D = np.delete(D, column_index_to_eleminate, 0)
C_numerated = np.delete(C_numerated, column_index_to_eleminate+1, 1)
print(f"x_num: {x_num}, y_num: {y_num}")
add_to_solutions(selected_value, x_num, y_num)
print("C")
print(C)
print("Numerated")
print(C_numerated)
print(selected_value)
print(solution_matrix)
Z_matrix = np.zeros((C_init_height, C_init_length), dtype=np.int64)
for y in range(C_init_height):
for x in range(C_init_length):
Z_matrix[y][x] = solution_matrix[y][x] * C_initial[y][x]
Z = np.sum(Z_matrix)
print(f"Z = {Z}")
result = Result(State.SOLVED, Z, solution_matrix)
return result
''' if target_array is not None:
objective_function_value = np.sum(np.dot(C, target_array))
return Result(State.SOLVED, objective_function_value, target_array)
else:
return Result(State.UNAPPLICABLE)'''
Vogel(S,C,D)
def Russell(
S: np.array,
C: np.array,
D: np.array) -> Result:
selected = np.zeros(C.shape)
remaining_rows = np.ones(C.shape[0], dtype=bool)
remaining_cols = np.ones(C.shape[1], dtype=bool)
x_0 = np.zeros(C.shape, dtype=np.int64)
it_count = 0
while True:
mask = np.outer(remaining_rows, remaining_cols)
u = np.max(np.where(mask, C, -M), axis=1)
v = np.max(np.where(mask, C, -M), axis=0)
d = np.zeros(C.shape, dtype=np.int64)
for i in range(C.shape[0]):
for j in range(C.shape[1]):
if selected[i][j]:
d[i][j] = M
else:
d[i][j] = C[i][j] - u[i] - v[j]
i, j = np.unravel_index(np.argmin(d, axis=None), d.shape)
if (D[j] == 0):
break
if (S[i] >= D[j]):
x_0[i][j] = D[j]
S[i] -= D[j]
D[j] = 0
remaining_cols[j] = 0
else:
x_0[i][j] = S[i]
D[j] -= S[i]
S[i] = 0
remaining_rows[i] = 0
selected[i][j] = 1
it_count += 1
if (it_count > 1000):
return Result(State.UNAPPLICABLE)
return Result(State.SOLVED, C * x_0, x_0)
def print_problem_statement(
S: np.array,
C: np.array,
D: np.array) -> None:
S = S.astype(object)
S = np.append(S, "_").reshape(-1, 1)
matrix = np.append(C, [D], axis=0)
matrix = np.hstack((matrix, S))
matrix = matrix.astype(object)
matrix[matrix == M] = "M"
table = ""
for y in range(len(matrix)):
row = ""
for x in range(len(matrix[0])):
if matrix[y][x] != "_":
if (x == len(matrix[0]) - 1):
row += f" |{matrix[y][x]}"
else:
row += f" {matrix[y][x]}"
if len(str(matrix[y][x])) == 1:
row += " "
if (y == len(matrix)-1):
table += f"\n{"_ " * ((len(matrix[0])-1) * 2)}"
table += f"\n{row}"
print(table)
print(print_problem_statement(S,C,D))
def solve(
S: np.array,
C: np.array,
D: np.array,
NWExpected: np.array,
VogelExpected: np.array,
RussellExpected: np.array,
) -> int:
print_problem_statement(S, C, D)
if (np.sum(S) != np.sum(D)):
print("The problem is not balanced!")
return 1
result1 = NorthwestCorner(S.copy(), C.copy(), D.copy())
result2 = Vogel(S.copy(), C.copy(), D.copy())
result3 = Russell(S.copy(), C.copy(), D.copy())
if (any([result1.solved == State.UNAPPLICABLE,
result2.solved == State.UNAPPLICABLE,
result3.solved == State.UNAPPLICABLE])):
print("The method is not applicable!")
return 1
if (not np.all(NWExpected == result1.solution)):
print("Incorrect initial basic feasible solution for North-West.\n",
f"Got:\n{result1.solution}.\n Expected:\n{NWExpected}.")
return 0
if (not np.all(VogelExpected == result2.solution)):
print("Incorrect initial basic feasible solution for Vogel's approximation.\n",
f"Got:\n{result2.solution}.\n Expected:\n{VogelExpected}.")
return 0
if (not np.all(RussellExpected == result3.solution)):
print("Incorrect initial basic feasible solution for Russell's approximation.\n",
f"Got:\n{result3.solution}.\nExpected:\n{RussellExpected}.")
return 0
print("North-West initial basic feasible solution:\n", result1.solution,
"\nVogel's approximation intial basic feasible solution:\n", result2.solution,
"\nRussell's approximation initial basic feasible solution:\n", result3.solution)
return 1
def TEST_CASE_1():
print("----------------------RUNNING_TEST_CASE_1----------------------")
C = np.array([
[16, 16, 13, 22, 17],
[14, 14, 13, 19, 15],
[19, 19, 20, 23, M],
[M, 0, M, 0, 0]
], dtype=np.int64)
S = np.array([
50, 60, 50, 50
], dtype=np.int64)
D = np.array([
30, 20, 70, 30, 60
], dtype=np.int64)
print_problem_statement(S, C, D)
NWExpected = np.array([
[30, 20, 0, 0, 0],
[0, 0, 60, 0, 0],
[0, 0, 10, 30, 10],
[0, 0, 0, 0, 50]
], dtype=np.int64)
VogelExpected = np.array([
[0, 0, 50, 0, 0],
[0, 0, 20, 0, 40],
[30, 20, 0, 0, 0],
[0, 0, 0, 30, 20]
], dtype=np.int64)
RussellExpected = np.array([
[0, 0, 40, 0, 10],
[30, 0, 30, 0, 0],
[0, 20, 0, 30, 0],
[0, 0, 0, 0, 50]
], dtype=np.int64)
return solve(S, C, D, NWExpected, VogelExpected, RussellExpected)
def TEST_CASE_2():
print("----------------------RUNNING_TEST_CASE_2----------------------")
C = np.array([[5, 8, 6],
[4, 7, 9],
[3, 8, 5]], dtype=np.int64)
S = np.array([20, 30, 25], dtype=np.int64)
D = np.array([10, 25, 40], dtype=np.int64)
print_problem_statement(S, C, D)
NWExpected = np.array([
[10, 10, 0],
[0, 15, 15],
[0, 0, 25],
], dtype=np.int64)
VogelExpected = np.array([
[0],
[0],
[0] # Заполнить
], dtype=np.int64)
RussellExpected = np.array([
[5, 0, 15],
[5, 25, 0],
[0, 0, 25]
], dtype=np.int64)
return solve(S, C, D, NWExpected, VogelExpected, RussellExpected)
def TEST_CASE_3():
print("----------------------RUNNING_TEST_CASE_3----------------------")
C = np.array([
[7, 8, 1, 2],
[4, 5, 9, 8],
[9, 2, 3, 6],
], dtype=np.int64)
S = np.array([
160, 140, 170
], dtype=np.int64)
D = np.array([
120, 50, 190, 110
], dtype=np.int64)
print_problem_statement(S, C, D)
NWExpected = np.array([
[120, 40, 0, 0],
[0, 10, 130, 0],
[0, 0, 60, 110]
], dtype=np.int64)
VogelExpected = np.array([
[0, 0, 50, 110],
[120, 20, 0, 0],
[0, 30, 140, 0],
], dtype=np.int64)
RussellExpected = np.array([
[0, 0, 160, 0],
[120, 0, 0, 20],
[0, 50, 30, 90],
], dtype=np.int64)
return solve(S, C, D, NWExpected, VogelExpected, RussellExpected)
if __name__ == "__main__":
tests = [TEST_CASE_1, TEST_CASE_2, TEST_CASE_3]
tests_passed = 0
for test in tests:
tests_passed += test()
print("----------------------RESULTS----------------------")
print(f"Total number of tests: {len(tests)}")
print(f"Total number of passed tests: {tests_passed}")