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Author: lshaw8317

examples/ndarray/blosc2_3_10_demo.py

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+import blosc2
+import time
+
+N, M = 5_000, 10_000
+dtype = blosc2.float64
+working_set = dtype().itemsize * (2 * N * M + N * N) / 2 ** 30
+print(f"Working set size of {round(working_set, 2)} GB")
+shape1 = (N, M)
+shape2 = (M, N)
+a = blosc2.ones(shape=shape1, urlpath="a.b2nd", mode='w', dtype=dtype)
+b = blosc2.full(fill_value=2., shape=shape2, urlpath="b.b2nd", mode='w', dtype=dtype)
+
+# Expression
+t0 = time.time()
+# Define the operands and expression
+expression, operands = "matmul(a, b) + sin(b[2])", {"a": a, "b": b}
+# Create a lazy expression
+lexpr = blosc2.lazyexpr(expression, operands)
+print(f"Result of {expression} will have shape {lexpr.shape} and dtype {lexpr.dtype}")
+# Save the lazy expression to the specified path
+url_path = "my_expr.b2nd"
+lexpr.save(urlpath=url_path, mode="w")
+dt = time.time() - t0
+print(f"Defined expression, got metadata, and persisted it on disk in {round(dt * 1000, 3)} ms!")
+
+# Reopen persistent expression, compute, and write to disk with blosc2
+t0 = time.time()
+lexpr = blosc2.open(urlpath=url_path)
+dt = time.time() - t0
+print(f"In {round(dt*1000, 3)} ms opened lazy expression: shape = {lexpr.shape}, dtype = {lexpr.dtype}")
+t1 = time.time()
+result1 = lexpr.compute(urlpath="result.b2nd", mode='w')
+t2 = time.time()
+print(f"blosc2 fetched operands from disk, computed {expression}, wrote to disk in: {t2 - t1:.3f} s")