Add matmul example (#701)

Author: mtsokol

Diff for: examples/matmul_example.py

@@ -0,0 +1,69 @@
+import importlib
+import os
+
+import sparse
+
+from utils import benchmark
+
+import numpy as np
+import scipy.sparse as sps
+
+LEN = 100000
+DENSITY = 0.00001
+ITERS = 3
+rng = np.random.default_rng(0)
+
+
+if __name__ == "__main__":
+    print("Matmul Example:\n")
+
+    a_sps = sps.random(LEN, LEN - 10, format="csr", density=DENSITY, random_state=rng) * 10
+    a_sps.sum_duplicates()
+    b_sps = sps.random(LEN - 10, LEN, format="csr", density=DENSITY, random_state=rng) * 10
+    b_sps.sum_duplicates()
+
+    # ======= Finch =======
+    os.environ[sparse._ENV_VAR_NAME] = "Finch"
+    importlib.reload(sparse)
+
+    a = sparse.asarray(a_sps)
+    b = sparse.asarray(b_sps)
+
+    @sparse.compiled
+    def sddmm_finch(a, b):
+        return sparse.sum(a[:, None, :] * sparse.permute_dims(b, (1, 0))[None, :, :], axis=-1)
+
+    # Compile
+    result_finch = sddmm_finch(a, b)
+    # Benchmark
+    benchmark(sddmm_finch, args=[a, b], info="Finch", iters=ITERS)
+
+    # ======= Numba =======
+    os.environ[sparse._ENV_VAR_NAME] = "Numba"
+    importlib.reload(sparse)
+
+    a = sparse.asarray(a_sps)
+    b = sparse.asarray(b_sps)
+
+    def sddmm_numba(a, b):
+        return a @ b
+
+    # Compile
+    result_numba = sddmm_numba(a, b)
+    # Benchmark
+    benchmark(sddmm_numba, args=[a, b], info="Numba", iters=ITERS)
+
+    # ======= SciPy =======
+    def sddmm_scipy(a, b):
+        return a @ b
+
+    a = a_sps
+    b = b_sps
+
+    result_scipy = sddmm_scipy(a, b)
+    # Benchmark
+    benchmark(sddmm_scipy, args=[a, b], info="SciPy", iters=ITERS)
+
+    # np.testing.assert_allclose(result_numba.todense(), result_scipy.toarray())
+    # np.testing.assert_allclose(result_finch.todense(), result_numba.todense())
+    # np.testing.assert_allclose(result_finch.todense(), result_scipy.toarray())