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Diffstat (limited to 'tests/float/float_format_ints.py')
| -rw-r--r-- | tests/float/float_format_ints.py | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/tests/float/float_format_ints.py b/tests/float/float_format_ints.py new file mode 100644 index 0000000000..0bf4baf12d --- /dev/null +++ b/tests/float/float_format_ints.py @@ -0,0 +1,31 @@ +# Test that integers format to exact values. + +for b in [13, 123, 457, 23456]: + for r in range(1, 10): + e_fmt = "{:." + str(r) + "e}" + f_fmt = "{:." + str(r) + "f}" + g_fmt = "{:." + str(r) + "g}" + for e in range(0, 5): + f = b * (10**e) + title = str(b) + " x 10^" + str(e) + print(title, "with format", e_fmt, "gives", e_fmt.format(f)) + print(title, "with format", f_fmt, "gives", f_fmt.format(f)) + print(title, "with format", g_fmt, "gives", g_fmt.format(f)) + +# Check that powers of 10 (that fit in float32) format correctly. +for i in range(31): + # It works to 12 digits on all platforms *except* qemu-arm, where + # 10^11 comes out as 10000000820 or something. + print("{:.7g}".format(float("1e" + str(i)))) + +# 16777215 is 2^24 - 1, the largest integer that can be completely held +# in a float32. +print("{:f}".format(16777215)) +# 4294967040 = 16777215 * 128 is the largest integer that is exactly +# represented by a float32 and that will also fit within a (signed) int32. +# The upper bound of our integer-handling code is actually double this, +# but that constant might cause trouble on systems using 32 bit ints. +print("{:f}".format(2147483520)) +# Very large positive integers can be a test for precision and resolution. +# This is a weird way to represent 1e38 (largest power of 10 for float32). +print("{:.6e}".format(float("9" * 30 + "e8"))) |