32 lines
1.4 KiB
Python
32 lines
1.4 KiB
Python
|
# 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")))
|