#57 matrix_multiply_recursive_general

src/solutions/chapter4/section1/exercise1.py

@@ -0,0 +1,42 @@
+from book.chapter4.section1 import matrix_multiply_recursive
+from book.data_structures import Matrix
+from util import range_of
+
+
+def matrix_multiply_recursive_general(A: Matrix, B: Matrix, C: Matrix, n: int) -> None:
+    """A generalized version of the recursive algorithm for multiplying two square matrices, supporting arbitrary matrix
+     dimensions.
+
+    Args:
+        A: the first square matrix to multiply
+        B: the second square matrix to multiply
+        C: the matrix to add to the result of the matrix multiplication
+        n: the dimension of matrices A and B
+    """
+    m = __next_power_of_2(n)
+    A_ = __extend_matrix(A, n, m)
+    B_ = __extend_matrix(B, n, m)
+    C_ = __extend_matrix(C, n, m)
+    matrix_multiply_recursive(A_, B_, C_, m)
+    __copy_result(C_, C, n)
+
+
+def __next_power_of_2(n: int) -> int:
+    res = 1
+    while res < n:
+        res *= 2
+    return res
+
+
+def __extend_matrix(source: Matrix, source_size: int, extended_size: int) -> Matrix:
+    extended = Matrix(extended_size, extended_size)
+    for i in range_of(1, to=source_size):
+        for j in range_of(1, to=source_size):
+            extended[i, j] = source[i, j]
+    return extended
+
+
+def __copy_result(extended: Matrix, original: Matrix, original_size: int) -> None:
+    for i in range_of(1, to=original_size):
+        for j in range_of(1, to=original_size):
+            original[i, j] = extended[i, j]

test/test_solutions/test_chapter4.py

@@ -0,0 +1,32 @@
+import numpy
+from hypothesis import given
+from hypothesis import strategies as st
+from hypothesis.strategies import integers
+from hypothesis.strategies import lists
+
+from book.data_structures import Matrix
+from solutions.chapter4.section1.exercise1 import matrix_multiply_recursive_general
+from test_case import ClrsTestCase
+from test_util import create_matrix
+
+
+class TestChapter4(ClrsTestCase):
+
+    @given(st.data())
+    def test_matrix_multiply_recursive_general(self, data):
+        n = data.draw(integers(min_value=1, max_value=15), label="Matrices dimension")
+        elements1 = data.draw(
+            lists(lists(integers(min_value=-1000, max_value=1000), min_size=n, max_size=n), min_size=n, max_size=n),
+            label="First matrix elements")
+        elements2 = data.draw(
+            lists(lists(integers(min_value=-1000, max_value=1000), min_size=n, max_size=n), min_size=n, max_size=n),
+            label="Second matrix elements")
+        A = create_matrix(elements1)
+        B = create_matrix(elements2)
+        C = Matrix(n, n)
+
+        matrix_multiply_recursive_general(A, B, C, n)
+
+        actual_product = create_matrix(numpy.matmul(elements1, elements2))
+
+        self.assertEqual(C, actual_product)