88 lines
2.8 KiB
Plaintext
88 lines
2.8 KiB
Plaintext
From: mark at chem.uwa.edu.au (Mark C Favas)
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Date: 28 Apr 99 04:42:36 GMT
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Subject: FP exception, core dump in Python 1.5.2 (Tim's doing <grin>)
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Message-ID: <mark.925274556@declan>
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Content-Length: 2561
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X-UID: 1609
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[Tim Peters suggests some code to generate INFs and NANs]
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>def _make_inf():
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> x = 2.0
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> x2 = x * x
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> i = 0
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> while i < 100 and x != x2:
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> x = x2
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> x2 = x * x
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> i = i + 1
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> if x != x2:
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> raise ValueError("This machine's floats go on forever!")
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> return x
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>PINF = _make_inf()
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>MINF = -PINF
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>NAN = PINF - PINF
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>if 1.0 + NAN == 1.0:
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> raise ValueError("This machine doesn't have NaNs, "
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> "'overflows' to a finite number, "
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> "or is 754-conformant but is using "
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> "a goofy rounding mode.")
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>PZERO = 0.0
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>MZERO = -PZERO
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[Mark tries it, and...]
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On my platform, (DEC Alpha, Digital Unix 4.0D, Python 1.5.2) I get... a core
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dump! (exclamation because it's one of the few Python core dumps I've seen).
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[code modified to print i, x, x2]
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python ieee.py
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0 2.0 4.0
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1 4.0 16.0
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2 16.0 256.0
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3 256.0 65536.0
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4 65536.0 4294967296.0
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5 4294967296.0 1.84467440737e+19
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6 1.84467440737e+19 3.40282366921e+38
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7 3.40282366921e+38 1.15792089237e+77
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8 1.15792089237e+77 1.34078079299e+154
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Floating exception (core dumped)
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Python 1.5.2 (#1, Apr 17 1999, 05:27:57) [C] on osf1V4
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Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
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>>>
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dbx /usr/local/bin/python core
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dbx version 3.11.10
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Type 'help' for help.
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Core file created by program "python"
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thread 0x5 signal Floating point exception at >*[nxm_thread_kill, 0x3ff8058a608] ret r31, (r26), 1
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(dbx) where
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> 0 nxm_thread_kill(0x140081940, 0x0, 0x1400b13c0, 0x0, 0x3ff00000000) [0x3ff8058a608]
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1 pthread_kill(0x0, 0x0, 0x11fffef20, 0x3ffc018a888, 0x3ff00000000) [0x3ff80577998]
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2 (unknown)() [0x3ff8056c234]
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3 (unknown)() [0x3ff807b22d8]
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4 (unknown)() [0x3ff807b3824]
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5 exc_unwind(0x3ff800d4544, 0x11fffdfe0, 0xabadabad00beed00, 0x1400b13c0, 0x3ff807b3af4) [0x3ff807b3864]
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6 exc_raise_signal_exception(0x86, 0x0, 0x12005b218, 0x1, 0x8) [0x3ff807b3af0]
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7 (unknown)() [0x3ff80578cc8]
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8 PyFloat_FromDouble(0x0, 0x0, 0x12006f404, 0x14005c770, 0x1200533cc) [0x12005b214]
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9 PyNumber_Multiply(0x1400b2988, 0x1400b13c0, 0x1400b13c0, 0x0, 0x3) [0x12006f400]
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(dbx)
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--
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Email - mark at chem.uwa.edu.au ,-_|\ Mark C Favas
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Phone - +61 9 380 3482 / \ Department of Chemistry
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Fax - +61 9 380 1005 ---> *_,-._/ The University of Western Australia
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v Nedlands
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Loc - 31.97 S, 115.81 E Western Australia 6009
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