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This commit is contained in:
2024-03-24 21:31:21 +03:00
parent a4ac272d64
commit 6f503ee003
3 changed files with 93 additions and 45 deletions

View File

@@ -50,34 +50,54 @@ def swap_first_non_zero(matrix, i):
return False, -1
def swap_max_row(matrix, i):
def swap_max_row(matrix, j):
n = matrix.shape[0]
col_max = abs(matrix[i, i])
max_j = i
for j in range(i, n):
if abs(matrix[j, i]) > col_max:
col_max = abs(matrix[j, i])
max_j = j
if i != max_j:
matrix[[i, max_j], :] = matrix[[max_j, i], :]
current = float("inf")
if matrix[j, j] != 0:
current = np.sum(np.abs(matrix[j, :])) / abs(matrix[j, j])
max_i = j
for i in range(j + 1, n):
if matrix[i, j] == 0 or matrix[j, i] == 0:
continue
return max_j
target_current = np.sum(np.abs(matrix[i, :])) / abs(matrix[i, i])
new = np.sum(np.abs(matrix[i, :])) / abs(matrix[i, j])
target_new = np.sum(np.abs(matrix[j, :])) / abs(matrix[j, i])
if current - new > target_new - target_current:
current = new
max_i = i
if j != max_i:
matrix[[j, max_i], :] = matrix[[max_i, j], :]
return max_i
def swap_max_column(matrix, i):
n = matrix.shape[0]
row_max = abs(matrix[i, i])
max_j = i
for j in range(i, n):
if abs(matrix[i, j]) > row_max and abs(matrix[i, i]) - abs(matrix[j, j]) > 0.0:
row_max = abs(matrix[i, j])
max_j = j
if i != max_j:
matrix[:, [i, max_j]] = matrix[:, [max_j, i]]
current = float("inf")
if matrix[i, i] != 0:
current = np.sum(np.abs(matrix[i, :])) / abs(matrix[i, i])
best_j = i
for j in range(i + 1, n):
if matrix[i, j] == 0 or matrix[j, i] == 0:
continue
return max_j
target_current = np.sum(np.abs(matrix[j, :])) / abs(matrix[j, j])
new = np.sum(np.abs(matrix[i, :])) / abs(matrix[i, j])
target_new = np.sum(np.abs(matrix[j, :])) / abs(matrix[j, i])
if current - new > target_new - target_current:
current = new
best_j = j
if i != best_j:
matrix[:, [i, best_j]] = matrix[:, [best_j, i]]
return best_j
def norm(matrix: np.matrix):

View File

@@ -14,17 +14,17 @@ A = np.matrix(
B = np.matrix([[15.5, 2.5, 8.6, 12.1]], dtype=np.float64).T
# A = np.matrix(
# [
# [14.4, -5.3, 14.3, -12.7],
# [23.4, -14.2, -5.4, 2.1],
# [6.3, -13.2, -6.5, 14.3],
# [5.6, 8.8, -6.7, -23.8],
# ],
# dtype=np.float64,
# )
A = np.matrix(
[
[14.4, -5.3, 14.3, -12.7],
[23.4, -14.2, -5.4, 2.1],
[6.3, -13.2, -6.5, 14.3],
[5.6, 8.8, -6.7, -23.8],
],
dtype=np.float64,
)
# B = np.matrix([[-14.4, 6.6, 9.4, 7.3]], dtype=np.float64).T
B = np.matrix([[-14.4, 6.6, 9.4, 7.3]], dtype=np.float64).T
# A = np.matrix(
@@ -48,7 +48,7 @@ B = np.matrix([[15.5, 2.5, 8.6, 12.1]], dtype=np.float64).T
# print(algorithm.cond(A))
# print(np.linalg.cond(A, p=float("inf")))
# koef = np.matrix([[1 / 10000000000000, 1/100000000000, 1, 1]], dtype=np.float64)
# koef = np.matrix([[1, 1, 1, 1]], dtype=np.float64)
# for i in range(A.shape[0]):
# A[i, :] *= koef[0, i]
# B[i, :] *= koef[0, i]

View File

@@ -1,3 +1,4 @@
from typing import List, Tuple
import algorithm
import numpy as np
@@ -13,28 +14,26 @@ def iterative_method(
alpha = np.copy(A)
beta = np.copy(B)
for i in range(n):
j = algorithm.swap_max_row(alpha, i)
if alpha[i, i] == 0:
return None
beta[[i, j], :] = beta[[j, i], :]
print(alpha)
swaps = []
for i in range(n):
j = algorithm.swap_max_column(alpha, i)
if alpha[i, i] == 0:
if not _swap_rows(alpha, beta):
return None
swaps.append((i, j))
success, swaps_ = _swap_columns(alpha)
if not success:
return None
swaps.extend(swaps_)
print(alpha)
print(alpha)
for i in range(n):
beta[i, 0] = beta[i, 0] / alpha[i, i]
X = np.copy(beta)
for i in range(n):
for j in range(n):
if i == j:
@@ -44,12 +43,13 @@ def iterative_method(
alpha[i, i] = 0
print(algorithm.cond(alpha))
print(algorithm.norm(alpha))
if algorithm.cond(alpha) >= 1.0:
if algorithm.norm(alpha) >= 1.0:
return None
i = 0
X = np.copy(beta)
while i < max_iterations:
i += 1
@@ -63,3 +63,31 @@ def iterative_method(
X[[i, j], :] = X[[j, i], :]
return X
def _swap_rows(a: np.matrix, b: np.matrix) -> bool:
n = a.shape[0]
for i in range(n):
j = algorithm.swap_max_row(a, i)
if a[i, i] == 0:
return False
b[[i, j], :] = b[[j, i], :]
return True
def _swap_columns(a: np.matrix) -> Tuple[bool, List[Tuple[int, int]] | None]:
n = a.shape[0]
swaps = []
for i in range(n):
j = algorithm.swap_max_column(a, i)
if a[i, i] == 0:
return False, None
if i != j:
swaps.append((i, j))
return True, swaps