Opened 4 years ago
Last modified 8 weeks ago
#22857 needs_work defect
Using symbolic variables in domain 'positive' makes Sage crash
Reported by: | egourgoulhon | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | sage-9.4 |
Component: | symbolics | Keywords: | |
Cc: | rws, tmonteil, slelievre | Merged in: | |
Authors: | Reviewers: | Eric Gourgoulhon | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
In Sage 7.6 and 8.0.beta2, we have
sage: a, b = var('a b', domain='positive') sage: bool((a-b)*b == 0) ;;; ;;; Detected access to protected memory, also kwown as 'bus or segmentation fault'. ;;; Jumping to the outermost toplevel prompt ;;; Erreur de segmentation (core dumped)
This was reported on this ask question.
Change History (15)
comment:1 Changed 4 years ago by
- Cc rws added
comment:2 Changed 4 years ago by
comment:3 Changed 4 years ago by
- Description modified (diff)
comment:4 Changed 4 years ago by
Can you isolate the actual sequence of maxima commands that lead to the error? Then it's possible to see if it's a bug in ECL or something in Maxima itself (the kind of error suggests it's something that is poorly handled in ECL)
comment:5 Changed 4 years ago by
I cannot reproduce it with:
sage: a, b = var('a b') sage: (a>0)._maxima_init_assume_() '(_SAGE_VAR_a)>(0)' sage: maxima.assume(_) [_SAGE_VAR_a>0] sage: (b>0)._maxima_init_assume_() '(_SAGE_VAR_b)>(0)' sage: maxima.assume(_) [_SAGE_VAR_b>0] sage: bool((a-b)*b==0) False
but I can make it disappear with:
diff --git a/src/sage/symbolic/expression.pyx b/src/sage/symbolic/expression.pyx index 01319b5e68..8522746f27 100644 --- a/src/sage/symbolic/expression.pyx +++ b/src/sage/symbolic/expression.pyx @@ -1786,7 +1786,7 @@ cdef class Expression(CommutativeRingElement): pynac_assume_rel(self._gobj) if str(s._sage_()[0]) in ['meaningless','inconsistent','redundant']: raise ValueError("Assumption is %s" % str(s._sage_()[0])) - _assumptions.append(self) + #_assumptions.append(self) def forget(self): """
Anyway, with the original trigger ECL goes into an infinite loop:
#114 0x00007ffd8f408645 in L125signdiff_special (v1xlhs=0x3b56401, v2xrhs=0x3b19fb1) at binary-ecl/compar.c:6765 #115 0x00007ffd8f3ffaaa in L124signdiff (v1x=<optimized out>) at binary-ecl/compar.c:6679 #116 0x00007ffd8f3f0bf2 in L123sign_mplus (v1x=0x3b56e81) at binary-ecl/compar.c:6420 #117 0x00007ffd8f409c73 in L108sign1 (v1x=<optimized out>) at binary-ecl/compar.c:5682 #118 0x00007ffd8f3fb620 in L104sign_ (v1x=0x3b56e81) at binary-ecl/compar.c:5304 #119 0x00007ffd8f408645 in L125signdiff_special (v1xlhs=0x3b19f51, v2xrhs=0x5ce7180) at binary-ecl/compar.c:6765 #120 0x00007ffd8f3ffaaa in L124signdiff (v1x=<optimized out>) at binary-ecl/compar.c:6679 #121 0x00007ffd8f3f0bf2 in L123sign_mplus (v1x=0x3b0b1a1) at binary-ecl/compar.c:6420 #122 0x00007ffd8f409c73 in L108sign1 (v1x=<optimized out>) at binary-ecl/compar.c:5682 #123 0x00007ffd8f3fb620 in L104sign_ (v1x=0x3b0b1a1) at binary-ecl/compar.c:5304
comment:6 Changed 4 years ago by
OK here the confirmation:
sage: a, b = var('a b') sage: (a>0)._maxima_init_assume_() '(_SAGE_VAR_a)>(0)' sage: maxima.assume(_) [_SAGE_VAR_a>0] sage: (b>0)._maxima_init_assume_() '(_SAGE_VAR_b)>(0)' sage: maxima.assume(_) [_SAGE_VAR_b>0] sage: maxima._eval_line('is (equal((_SAGE_VAR_a-_SAGE_VAR_b)*_SAGE_VAR_b,0))') /home/ralf/sage/local/lib/python2.7/site-packages/sage/interfaces/maxima.pyc in _eval_line(self, line, allow_use_file, wait_for_prompt, reformat, error_check, restart_if_needed) 791 assert line_echo.strip().endswith(line.strip()), 'mismatch:\n' + line_echo + line 792 --> 793 self._expect_expr(self._display_prompt) 794 out = self._before() # input echo + output prompt + output 795 if error_check: /home/ralf/sage/local/lib/python2.7/site-packages/sage/interfaces/maxima.pyc in _expect_expr(self, expr, timeout) 713 i = self._expect.expect(expr,timeout=timeout) 714 else: --> 715 i = self._expect.expect(expr) 716 if i > 0: 717 v = self._expect.before /home/ralf/sage/local/lib/python2.7/site-packages/pexpect/spawnbase.pyc in expect(self, pattern, timeout, searchwindowsize, async) 319 compiled_pattern_list = self.compile_pattern_list(pattern) 320 return self.expect_list(compiled_pattern_list, --> 321 timeout, searchwindowsize, async) 322 323 def expect_list(self, pattern_list, timeout=-1, searchwindowsize=-1, /home/ralf/sage/local/lib/python2.7/site-packages/pexpect/spawnbase.pyc in expect_list(self, pattern_list, timeout, searchwindowsize, async) 343 return expect_async(exp, timeout) 344 else: --> 345 return exp.expect_loop(timeout) 346 347 def expect_exact(self, pattern_list, timeout=-1, searchwindowsize=-1, /home/ralf/sage/local/lib/python2.7/site-packages/pexpect/expect.pyc in expect_loop(self, timeout) 103 timeout = end_time - time.time() 104 except EOF as e: --> 105 return self.eof(e) 106 except TIMEOUT as e: 107 return self.timeout(e) /home/ralf/sage/local/lib/python2.7/site-packages/pexpect/expect.pyc in eof(self, err) 48 if err is not None: 49 msg = str(err) + '\n' + msg ---> 50 raise EOF(msg) 51 52 def timeout(self, err=None): EOF: End Of File (EOF). Exception style platform. Maxima with PID 23086 running /home/ralf/sage/local/bin/maxima --userdir=/home/ralf/.sage/maxima -p /home/ralf/sage/local/bin/sage-maxima.lisp command: /home/ralf/sage/local/bin/maxima args: ['/home/ralf/sage/local/bin/maxima', '--userdir=/home/ralf/.sage/maxima', '-p', '/home/ralf/sage/local/bin/sage-maxima.lisp'] buffer (last 100 chars): '' before (last 100 chars): "y, also kwown as 'bus or segmentation fault'.\r\n;;; Jumping to the outermost toplevel prompt\r\n;;;\r\n\r\n" after: <class 'pexpect.exceptions.EOF'> match: None match_index: None exitstatus: None flag_eof: True pid: 23086 child_fd: 14 closed: False timeout: None delimiter: <class 'pexpect.exceptions.EOF'> logfile: None logfile_read: None logfile_send: None maxread: 4194304 ignorecase: False searchwindowsize: None delaybeforesend: None delayafterclose: 0.1 delayafterterminate: 0.1 searcher: searcher_re: 0: re.compile("<sage-display>") sage:
comment:7 Changed 2 years ago by
Just to tell that the bug is still there in Sage 8.7.beta3.
comment:8 Changed 9 months ago by
- Milestone changed from sage-8.0 to sage-9.2
Still there in 9.2.beta3
comment:10 follow-up: ↓ 11 Changed 7 months ago by
- Cc tmonteil slelievre added
- Milestone changed from sage-9.2 to sage-duplicate/invalid/wontfix
- Status changed from new to needs_review
Looks like this was fixed by #30063
comment:11 in reply to: ↑ 10 Changed 7 months ago by
comment:12 Changed 7 months ago by
- Reviewers set to Eric Gourgoulhon
- Status changed from needs_review to positive_review
comment:13 Changed 7 months ago by
- Milestone changed from sage-duplicate/invalid/wontfix to sage-9.2
- Priority changed from critical to minor
- Status changed from positive_review to needs_work
No doctest was added for this at #30063. We should add one here.
comment:14 Changed 6 months ago by
- Milestone changed from sage-9.2 to sage-9.3
comment:15 Changed 8 weeks ago by
- Milestone changed from sage-9.3 to sage-9.4
Setting new milestone based on a cursory review of ticket status, priority, and last modification date.
in my machine (mac osx 10.11.6) the command works in v7.5.1, but breaks in v8.0beta2.