# check cases converting float to int, relying only on single precision float import struct import sys maxsize_bits = 0 maxsize = sys.maxsize while maxsize: maxsize >>= 1 maxsize_bits += 1 # work out configuration values is_64bit = maxsize_bits > 32 # 0 = none, 1 = long long, 2 = mpz ll_type = None if is_64bit: if maxsize_bits < 63: ll_type = 0 else: if maxsize_bits < 31: ll_type = 0 if ll_type is None: one = 1 if one << 65 < one << 62: ll_type = 1 else: ll_type = 2 # basic conversion # fmt: off print(int(14187745.)) print("%d" % 14187745.) # fmt: on if ll_type == 2: print(int(2.0**100)) print("%d" % 2.0**100) testpass = True p2_rng = ((30, 63, 127), (62, 63, 127))[is_64bit][ll_type] for i in range(0, p2_rng): bitcnt = len(bin(int(2.0**i))) - 3 if i != bitcnt: print("fail: 2.**%u was %u bits long" % (i, bitcnt)) testpass = False print("power of 2 test: %s" % (testpass and "passed" or "failed")) # TODO why does 10**12 fail this test for single precision float? testpass = True p10_rng = 9 if (ll_type == 0 and ~is_64bit) else 11 for i in range(0, p10_rng): digcnt = len(str(int(10.0**i))) - 1 if i != digcnt: print("fail: 10.**%u was %u digits long" % (i, digcnt)) testpass = False print("power of 10 test: %s" % (testpass and "passed" or "failed")) def fp2int_test(num, name, should_fail): try: x = int(num) passed = ~should_fail except: passed = should_fail print("%s: %s" % (name, passed and "passed" or "failed")) if ll_type != 2: if ll_type == 0: if is_64bit: neg_bad_fp = -1.00000005 * 2.0**62.0 pos_bad_fp = 2.0**62.0 neg_good_fp = -(2.0**62.0) pos_good_fp = 0.99999993 * 2.0**62.0 else: neg_bad_fp = -1.00000005 * 2.0**30.0 pos_bad_fp = 2.0**30.0 neg_good_fp = -(2.0**30.0) pos_good_fp = 0.9999999499 * 2.0**30.0 else: neg_bad_fp = -0.51 * 2.0**64.0 pos_bad_fp = 2.0**63.0 neg_good_fp = -(2.0**63.0) pos_good_fp = 1.9999998 * 2.0**62.0 fp2int_test(neg_bad_fp, "neg bad", True) fp2int_test(pos_bad_fp, "pos bad", True) fp2int_test(neg_good_fp, "neg good", False) fp2int_test(pos_good_fp, "pos good", False) else: fp2int_test(-1.999999879 * 2.0**127.0, "large neg", False) fp2int_test(1.999999879 * 2.0**127.0, "large pos", False) fp2int_test(float("inf"), "inf test", True) fp2int_test(float("nan"), "NaN test", True) # test numbers < 1 (this used to fail; see issue #1044) fp2int_test(0.0001, "small num", False) struct.pack("I", int(1 / 2))