[pypy-dev] Two bugs in PyPy 1.2

Fredrik Johansson fredrik.johansson at gmail.com
Fri Mar 12 22:01:52 CET 2010

(Note: Trying a second time, since the mail does not seem to have arrived on
the first try. Sorry if it's a duplicate.)

Dear PyPy developers,

I have found two bugs while trying to run mpmath on pypy-1.2. This is with
the Windows binary:

Python 2.5.2 (72130, Mar 12 2010, 12:25:40)
[PyPy 1.2.0] on win32

My system is an HP 530, Intel Celeron M 520 @ 1.60 GHz, 1024 MB RAM running
Windows XP.

The first bug is an incompatibility with CPython. In CPython, builtin float
functions accept arbitrary objects as long as they have a __float__ method.
Consider the following code:

class x(object):
    def __float__(self): return 1.0

class y(object):
    def __complex__(self): return 1.0j

import math; math.log(x())
import cmath; cmath.log(x())
import cmath; cmath.log(y())

CPython 2.6 gives:

CPython 2.5 gives:
TypeError: a float is required

PyPy gives:
TypeError: expected float, got x object
TypeError: expected float, got x object

Presumably PyPy should do the same thing as 2.6 here.

Secondly, there is an error somewhere in the long multiplication code:

Python 2.5.2 (72130, Mar 12 2010, 12:25:40)
[PyPy 1.2.0] on win32
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``no random bugs in random,
>>>> import mpmath
>>>> mpmath.runtests()
mpmath imported from C:\pypy12\lib-python\2.5.2\mpmath
mpmath backend: python
mpmath mp class: <mpmath.ctx_mp.MPContext object at 0x0000001a>
mpmath version: 0.15-svn
Python version: 2.5.2 (72130, Mar 12 2010, 12:25:40)
[PyPy 1.2.0]


    agm                       ok        0.0446171 s
    airy                      ok        0.1957078 s
    appellf1                  ok        1.1814778 s
    bessel                    ok        0.6132425 s
    coulomb                   ok        0.4926749 s
    e1                        ok        0.0109151 s
    ei                        ok        0.0346402 s
    elliptic_integrals        ok        0.2575911 s
    erf                       ok        0.3858091 s
    exp_integrals             ok        0.0715859 s
    RPython traceback:
  File "implement_4.c", line 35008, in
  File "implement_9.c", line 47885, in __mm_mul_W_LongObject_W_LongObject
  File "implement_13.c", line 3727, in _k_lopsided_mul
  File "implement_9.c", line 38027, in _k_mul
Fatal RPython error: AssertionError

The test that triggers the failure is "from mpmath import expint;
expint('1.01', '1e-1000')".

For your convenience, I have tracked down the precise numbers. Since they
have several hundred digits, I put them in an attachment.

Thank you for your hard work!

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