32 lines
1.4 KiB
Python
32 lines
1.4 KiB
Python
# Test that integers format to exact values.
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for b in [13, 123, 457, 23456]:
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for r in range(1, 10):
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e_fmt = "{:." + str(r) + "e}"
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f_fmt = "{:." + str(r) + "f}"
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g_fmt = "{:." + str(r) + "g}"
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for e in range(0, 5):
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f = b * (10**e)
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title = str(b) + " x 10^" + str(e)
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print(title, "with format", e_fmt, "gives", e_fmt.format(f))
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print(title, "with format", f_fmt, "gives", f_fmt.format(f))
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print(title, "with format", g_fmt, "gives", g_fmt.format(f))
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# Check that powers of 10 (that fit in float32) format correctly.
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for i in range(31):
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# It works to 12 digits on all platforms *except* qemu-arm, where
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# 10^11 comes out as 10000000820 or something.
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print("{:.7g}".format(float("1e" + str(i))))
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# 16777215 is 2^24 - 1, the largest integer that can be completely held
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# in a float32.
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print("{:f}".format(16777215))
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# 4294967040 = 16777215 * 128 is the largest integer that is exactly
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# represented by a float32 and that will also fit within a (signed) int32.
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# The upper bound of our integer-handling code is actually double this,
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# but that constant might cause trouble on systems using 32 bit ints.
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print("{:f}".format(2147483520))
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# Very large positive integers can be a test for precision and resolution.
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# This is a weird way to represent 1e38 (largest power of 10 for float32).
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print("{:.6e}".format(float("9" * 30 + "e8")))
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