mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-12-18 09:10:16 +00:00
441b82a95f
* added matrix minor * added matrix determinant * added inverse,scalar multiply, identity, transpose
76 lines
2.1 KiB
Python
76 lines
2.1 KiB
Python
def add(matrix_a, matrix_b):
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rows = len(matrix_a)
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columns = len(matrix_a[0])
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matrix_c = []
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for i in range(rows):
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list_1 = []
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for j in range(columns):
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val = matrix_a[i][j] + matrix_b[i][j]
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list_1.append(val)
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matrix_c.append(list_1)
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return matrix_c
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def scalarMultiply(matrix , n):
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return [[x * n for x in row] for row in matrix]
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def multiply(matrix_a, matrix_b):
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matrix_c = []
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n = len(matrix_a)
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for i in range(n):
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list_1 = []
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for j in range(n):
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val = 0
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for k in range(n):
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val = val + matrix_a[i][k] * matrix_b[k][j]
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list_1.append(val)
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matrix_c.append(list_1)
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return matrix_c
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def identity(n):
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return [[int(row == column) for column in range(n)] for row in range(n)]
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def transpose(matrix):
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return map(list , zip(*matrix))
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def minor(matrix, row, column):
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minor = matrix[:row] + matrix[row + 1:]
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minor = [row[:column] + row[column + 1:] for row in minor]
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return minor
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def determinant(matrix):
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if len(matrix) == 1: return matrix[0][0]
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res = 0
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for x in range(len(matrix)):
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res += matrix[0][x] * determinant(minor(matrix , 0 , x)) * (-1) ** x
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return res
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def inverse(matrix):
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det = determinant(matrix)
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if det == 0: return None
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matrixMinor = [[] for _ in range(len(matrix))]
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for i in range(len(matrix)):
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for j in range(len(matrix)):
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matrixMinor[i].append(determinant(minor(matrix , i , j)))
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cofactors = [[x * (-1) ** (row + col) for col, x in enumerate(matrixMinor[row])] for row in range(len(matrix))]
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adjugate = transpose(cofactors)
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return scalarMultiply(adjugate , 1/det)
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def main():
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matrix_a = [[12, 10], [3, 9]]
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matrix_b = [[3, 4], [7, 4]]
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matrix_c = [[11, 12, 13, 14], [21, 22, 23, 24], [31, 32, 33, 34], [41, 42, 43, 44]]
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matrix_d = [[3, 0, 2], [2, 0, -2], [0, 1, 1]]
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print(add(matrix_a, matrix_b))
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print(multiply(matrix_a, matrix_b))
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print(identity(5))
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print(minor(matrix_c , 1 , 2))
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print(determinant(matrix_b))
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print(inverse(matrix_d))
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if __name__ == '__main__':
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main()
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