WUT_Computer_Science/code/matrix_generator.py

87 lines
3.7 KiB
Python

import numpy as np
import scipy.io
import os
class MatrixGenerator:
@staticmethod
def generate_spd_matrix(n: int) -> np.ndarray:
A = np.random.rand(n, n)
spd_matrix = np.dot(A, A.T) + n * MatrixGenerator.generate_identity_matrix(n) # Adding n*I ensures positive definiteness
return spd_matrix
@staticmethod
def generate_identity_matrix(size):
return np.eye(size)
@staticmethod
def generate_alternating_vector(size):
return np.tile([1, 2], int(np.ceil(size / 2)))[:size]
@staticmethod
def get_matrix_from_file(file_path, problem):
mat_contents = scipy.io.loadmat(file_path)
problem_record = mat_contents['Problem'][0][0]
A = problem_record[problem]
if scipy.sparse.issparse(A):
A_dense = A.todense()
else:
A_dense = A
return np.array(A_dense)
@staticmethod
def generate_matrix_and_vector(type, size=None):
if type == 'spd':
if size is None:
raise ValueError("Size must be provided for SPD matrix generation.")
try:
matrix, vector, lambda_min, lambda_max = MatrixGenerator.load_from_file("spd_"+str(size)+".npz")
except FileNotFoundError as e:
matrix = MatrixGenerator.generate_spd_matrix(size)
vector = np.random.uniform(-1, 1, size)
lambda_min, lambda_max = MatrixGenerator.calculate_eigenvalues(matrix)
MatrixGenerator.save_to_file(matrix, vector, lambda_min, lambda_max, "spd_"+str(size)+".npz")
elif type == 'nemeth12':
try:
matrix, vector, lambda_min, lambda_max = MatrixGenerator.load_from_file("nemeth12.npz")
except FileNotFoundError as e:
matrix = -1 * MatrixGenerator.get_matrix_from_file("nemeth12.mat", 1)
size = matrix.shape[0]
vector = MatrixGenerator.generate_alternating_vector(size)
lambda_min, lambda_max = MatrixGenerator.calculate_eigenvalues(matrix)
MatrixGenerator.save_to_file(matrix, vector, lambda_min, lambda_max, "nemeth12.npz")
elif type == 'poli3':
try:
matrix, vector, lambda_min, lambda_max = MatrixGenerator.load_from_file("poli3.npz")
except FileNotFoundError as e:
matrix = MatrixGenerator.get_matrix_from_file("poli3.mat", 2)
size = matrix.shape[0]
vector = MatrixGenerator.generate_alternating_vector(size)
lambda_min, lambda_max = MatrixGenerator.calculate_eigenvalues(matrix)
MatrixGenerator.save_to_file(matrix, vector, lambda_min, lambda_max, "poli3.npz")
else:
raise ValueError("Invalid type specified. Choose 'spd', 'nemeth12', or 'poli3'.")
return matrix, vector, lambda_min, lambda_max
@staticmethod
def calculate_eigenvalues(A):
eigenvalues = np.linalg.eigvals(A)
lambda_min = np.min(eigenvalues)
lambda_max = np.max(eigenvalues)
return lambda_min, lambda_max
@staticmethod
def save_to_file(matrix, vector, lambda_min, lambda_max, file_path):
np.savez(file_path, matrix=matrix, vector=vector, lambda_min=lambda_min, lambda_max=lambda_max)
def load_from_file(file_path):
if not os.path.exists(file_path):
raise FileNotFoundError(f"The file {file_path} does not exist.")
data = np.load(file_path)
matrix = data['matrix']
vector = data['vector']
lambda_min = data['lambda_min']
lambda_max = data['lambda_max']
return matrix, vector, lambda_min, lambda_max