Unable to start singular because the command 'Singular -t --ticks-per-sec 1000' failed

[e14f4152-4982-4ace-8c95-73a0599b109b]

Reported by Dan Drake on sage-devel and sage-release:

Two builds of 4.3.4 are not doctesting properly for me; both are failing
the doctest for free_module.py because Singular won't start. The
failures always end with "TypeError: Unable to start singular because
the command 'Singular -t --ticks-per-sec 1000' failed."

This happens on two virtual machines: one running Ubuntu Hardy, the
other running Ubuntu Lucid. I've tried rebuilding Singular, but it
didn't work in either case. I tried a couple of the doctests manually,
and they seemed to work, and I can start Singular using the above
command with no troubles.

I've built 4.3.4 on two different machines (not virtual machines) and
everything works fine. I'm attaching a log of the failed doctest. Any
ideas? 

Tracebacks:

sage -t  "devel/sage/sage/modules/free_module.py"           
**********************************************************************
File "/home/alex/sage-4.3.4/devel/sage/sage/modules/free_module.py", line 2533:
    sage: W = M.submodule([x*B[0], 2*B[1]- x*B[2]]); W
Exception raised:
    Traceback (most recent call last):
      File "/home/alex/sage-4.3.4/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/home/alex/sage-4.3.4/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/home/alex/sage-4.3.4/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_69[11]>", line 1, in <module>
        W = M.submodule([x*B[Integer(0)], Integer(2)*B[Integer(1)]- x*B[Integer(2)]]); W###line 2533:
    sage: W = M.submodule([x*B[0], 2*B[1]- x*B[2]]); W
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 2545, in submodule
        V = self.span(gens, check=check, already_echelonized=already_echelonized)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 2461, in span
        self.ambient_module(), gens, check=check, already_echelonized=already_echelonized)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 5446, in __init__
        echelonize=True, already_echelonized=already_echelonized)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4553, in __init__
        basis = self._echelonized_basis(ambient, basis)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4666, in _echelonized_basis
        d = self._denominator(basis)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4774, in _denominator
        d = sage.rings.integer.Integer(B[0].denominator())
      File "free_module_element.pyx", line 958, in sage.modules.free_module_element.FreeModuleElement.denominator (sage/modules/free_module_element.c:8071)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 343, in lcm
        return lcm_func(self, singular, have_ring)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 451, in lcm_func
        lcm = self._singular_(have_ring=have_ring).lcm(right._singular_(have_ring=have_ring))
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 339, in _singular_
        return _singular_func(self, singular, have_ring)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 383, in _singular_func
        self.parent()._singular_(singular).set_ring() #this is expensive
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 196, in _singular_
        return self._singular_init_(singular)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 241, in _singular_init_
        self.__singular = singular.ring(self.characteristic(), _vars, order=order, check=False)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 897, in ring
        R = self('%s,%s,%s'%(char, vars, order), 'ring')
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 660, in __call__
        return SingularElement(self, type, x, False)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 1109, in __init__
        raise TypeError, x
    TypeError: Unable to start singular because the command 'Singular -t --ticks-per-sec 1000' failed.

**********************************************************************
File "/home/alex/sage-4.3.4/devel/sage/sage/modules/free_module.py", line 2538:
    sage: W.ambient_module()
Expected:
    Ambient free module of rank 3 over the principal ideal domain Univariate Polynomial Ring in x over Rational Field
Got:
    Ambient free module of rank 3 over the principal ideal domain Integer Ring
**********************************************************************
File "/home/alex/sage-4.3.4/devel/sage/sage/modules/free_module.py", line 2681:
    sage: W = M.submodule_with_basis([x*B[0], 2*B[0]- x*B[2]]); W
Exception raised:
    Traceback (most recent call last):
      File "/home/alex/sage-4.3.4/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/home/alex/sage-4.3.4/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/home/alex/sage-4.3.4/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_71[15]>", line 1, in <module>
        W = M.submodule_with_basis([x*B[Integer(0)], Integer(2)*B[Integer(0)]- x*B[Integer(2)]]); W###line 2681:
    sage: W = M.submodule_with_basis([x*B[0], 2*B[0]- x*B[2]]); W
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 2687, in submodule_with_basis
        V = self.span_of_basis(basis=basis, check=check, already_echelonized=already_echelonized)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 2602, in span_of_basis
        already_echelonized=already_echelonized)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4577, in __init__
        w = self._echelonized_basis(ambient, basis)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4666, in _echelonized_basis
        d = self._denominator(basis)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/modules/free_module.py", line 4774, in _denominator
        d = sage.rings.integer.Integer(B[0].denominator())
      File "free_module_element.pyx", line 958, in sage.modules.free_module_element.FreeModuleElement.denominator (sage/modules/free_module_element.c:8071)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 343, in lcm
        return lcm_func(self, singular, have_ring)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 451, in lcm_func
        lcm = self._singular_(have_ring=have_ring).lcm(right._singular_(have_ring=have_ring))
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 339, in _singular_
        return _singular_func(self, singular, have_ring)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 383, in _singular_func
        self.parent()._singular_(singular).set_ring() #this is expensive
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 196, in _singular_
        return self._singular_init_(singular)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 241, in _singular_init_
        self.__singular = singular.ring(self.characteristic(), _vars, order=order, check=False)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 897, in ring
        R = self('%s,%s,%s'%(char, vars, order), 'ring')
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 660, in __call__
        return SingularElement(self, type, x, False)
      File "/home/alex/sage-4.3.4/local/lib/python/site-packages/sage/interfaces/singular.py", line 1109, in __init__
        raise TypeError, x
    TypeError: Unable to start singular because the command 'Singular -t --ticks-per-sec 1000' failed.

**********************************************************************
2 items had failures:
   2 of  13 in __main__.example_69
   1 of  16 in __main__.example_71
***Test Failed*** 3 failures.
For whitespace errors, see the file /home/alex/.sage//tmp/.doctest_free_module.py
 [13.0 s]

Minh Nguyen reports seeing the same error a GCC compile farm Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz) with a trial "final" 4.5.3 (essentially the same as 4.5.3.rc0). Here is the test log.

CC: @dandrake @sagetrac-mvngu @alexanderdreyer

Component: interfaces

Keywords: pexpect EOF crash exception

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/9865

[e14f4152-4982-4ace-8c95-73a0599b109b]

comment:1

I've just seen this error while testing the trial "final" 4.5.3 on t2:

sage -t -long  devel/sage/sage/crypto/mq/sr.py
**********************************************************************
File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/devel/sage-main/sage/crypto/mq/sr.py", line 118:
    sage: for V in I.variety():
       for k,v in sorted(V.iteritems()):
          print k,v
       print
Exception raised:
    Traceback (most recent call last):
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_0[20]>", line 1, in <module>
        for V in I.variety():###line 118:
    sage: for V in I.variety():
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 407, in __call__
        return self.f(self._instance, *args, **kwds)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 2092, in variety
        d = self.dimension()
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 407, in __call__
        return self.f(self._instance, *args, **kwds)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1010, in dimension
        v = self._groebner_basis_singular_raw()
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1175, in _groebner_basis_singular_raw
        S = self._singular_().groebner()
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 517, in _singular_
        self.ring()._singular_(singular).set_ring()
      File "sage_object.pyx", line 583, in sage.structure.sage_object.SageObject._singular_ (sage/structure/sage_object.c:6315)
      File "sage_object.pyx", line 379, in sage.structure.sage_object.SageObject._interface_ (sage/structure/sage_object.c:3374)
      File "pbori.pyx", line 1190, in sage.rings.polynomial.pbori.BooleanPolynomialRing._singular_init_ (sage/rings/polynomial/pbori.cpp:10968)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/rings/quotient_ring.py", line 756, in _singular_init_
        self.__R._singular_().set_ring()
      File "multi_polynomial_libsingular.pyx", line 994, in sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular._singular_ (sage/rings/polynomial/multi_polynomial_libsingular.cpp:9038)
      File "multi_polynomial_libsingular.pyx", line 1135, in sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular._singular_init_ (sage/rings/polynomial/multi_polynomial_libsingular.cpp:9607)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 890, in ring
        self.eval(s)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 546, in eval
        s = Expect.eval(self, x, **kwds)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 983, in eval
        return '\n'.join([self._eval_line(L, **kwds) for L in code.split('\n') if L != ''])
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 634, in _eval_line
        return self._eval_line_using_file(line)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 621, in _eval_line_using_file
        s = self._eval_line(self._read_in_file_command(tmp_to_use), allow_use_file=False)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 637, in _eval_line
        self._start()
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 375, in _start
        Expect._start(self, alt_message)
      File "/scratch/mpatel/tmp/bb/slave/t2_scratch/build/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 458, in _start
        self.__name, cmd, self._install_hints())
    RuntimeError: Unable to start singular because the command 'Singular -t --ticks-per-sec 1000' failed.

**********************************************************************
1 items had failures:
   1 of  28 in __main__.example_0
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mpatel/.sage/tmp/.doctest_sr.py

[e14f4152-4982-4ace-8c95-73a0599b109b]

Description changed:

--- 
+++ 
@@ -18,7 +18,7 @@

Tracebacks:

- +python sage -t "devel/sage/sage/modules/free_module.py"

---

File "/home/alex/sage-4.3.4/devel/sage/sage/modules/free_module.py", line 2533: @@ -128,4 +128,4 @@ [13.0 s]

-Minh Nguyen reports seeing the same error a Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz).  [Here](http://wiki.sagemath.org/devel/BuildFarm/sage-4.5.3?action=AttachFile&do=get&target=gcc100.fsffrance.log.bz2) is the test log.
+Minh Nguyen reports seeing the same error a Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz) with a trial "final" 4.5.3 (essentially the same as 4.5.3.rc0).  [Here](http://wiki.sagemath.org/devel/BuildFarm/sage-4.5.3?action=AttachFile&do=get&target=gcc100.fsffrance.log.bz2) is the test log.

[e14f4152-4982-4ace-8c95-73a0599b109b]

comment:2

In my case, the test passed when I ran it again. I could not reproduce it.

[e14f4152-4982-4ace-8c95-73a0599b109b]

Description changed:

--- 
+++ 
@@ -128,4 +128,4 @@
     [13.0 s]

-Minh Nguyen reports seeing the same error a Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz) with a trial "final" 4.5.3 (essentially the same as 4.5.3.rc0). Here is the test log. +Minh Nguyen reports seeing the same error a GCC compile farm Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz) with a trial "final" 4.5.3 (essentially the same as 4.5.3.rc0). Here is the test log.

[ba2de90a-bb52-4931-8573-7586330e60db]

comment:4

I remember having the same failure in free_module.py and I think its most likely caused by having not sufficient memory - everytime I run free_module.py's my system (i686 + 1GB RAM + 512 MB swap) is heavily using swap.

Also, rebooting and running the test again made the test pass back then.

[83660e46-0051-498b-a8c1-f7a7bd232b5a]

comment:7

Replying to @dandrake:

Replying to @cschwan:

I remember having the same failure in free_module.py and I think its most likely caused by having not sufficient memory - everytime I run free_module.py's my system (i686 + 1GB RAM + 512 MB swap) is heavily using swap.

Interesting. On the Arch VM where I was seeing the same problem, increasing the RAM allocated to the VM from 1152 MB up to 1768 MB seems to fix the problem. (Using 4.5.3.alpha2.) But there are still questions: why do the tests pass when run in Sage normally? Does the doctest framework really take 600+ MB of memory? And why exactly does Singular fail to start -- is it just unable to allocate enough memory? If so, can we get a better error message? These tests seem to work on non-VMs with less memory -- or do they? Why is that?

I've successfully built and ptestlonged recent versions of Sage on e.g.:

• Single-core (no HT either) with only 768 MB (and GUI running), and I believe half of that would not cause swapping. (IIRC built with 2 jobs, tested with only one thread.)
• Quad-core (no HT) with 8 GB: Built with 32 jobs, ptestlong with 64(!) threads without swapping. (I then only further tried ptestlong with 128 threads, which as expected caused massive swapping s.t. almost all tests timed out.)

I recently examined the memory consumption of testing files in sage/schemes/elliptic_curves since these were said to be the record holders. The "winner" of these was sha_tate.py with a peak usage (just that process) of 226 MB.

[83660e46-0051-498b-a8c1-f7a7bd232b5a]

comment:8

lol, I've just built Sage 4.5.3 on the (single-core) Pentium 4 with 768 MB RAM, and it seems I now get doctest errors due to Singular crashing while running ptestlong with two threads...

More to come; the test is still running.

[83660e46-0051-498b-a8c1-f7a7bd232b5a]

Changed keywords from none to pexpect EOF crash exception

[83660e46-0051-498b-a8c1-f7a7bd232b5a]

comment:9

Replying to @nexttime:

lol, I've just built Sage 4.5.3 on the (single-core) Pentium 4 with 768 MB RAM, and it seems I now get doctest errors due to Singular crashing while running ptestlong with two threads...

More to come; the test is still running.

2 threads were perhaps too much for that old machine (CPU, not RAM), though the build went fine with three jobs.

As reported by me on sage-release, ptestlong gave one timeout and two doctest failures due to Singular having "crashed" (plus two NameErrors as a result of that):

sage -t  -long devel/sage/sage/rings/polynomial/multi_polynomial_element.py
**********************************************************************
File "/home/leif/Sage/sage-4.5.3/devel/sage-main/sage/rings/polynomial/multi_polynomial_element.py", line 1513:
    sage: M = f.lift(I)
Exception raised:
    Traceback (most recent call last):
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_49[5]>", line 1, in <module>
        M = f.lift(I)###line 1513:
    sage: M = f.lift(I)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/multi_polynomial_element.py", line 1519, in lift
        fs = self._singular_()
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 347, in _singular_
        return _singular_func(self, singular, have_ring)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 391, in _singular_func
        self.parent()._singular_(singular).set_ring() #this is expensive
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 195, in _singular_
        return self._singular_init_(singular)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/rings/polynomial/polynomial_singular_interface.py", line 236, in _singular_init_
        self.__singular = singular.ring("(complex,%d,0,I)"%digits, _vars,  order=order, check=False)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 890, in ring
        self.eval(s)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 546, in eval
        s = Expect.eval(self, x, **kwds)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 983, in eval
        return '\n'.join([self._eval_line(L, **kwds) for L in code.split('\n') if L != ''])
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 637, in _eval_line
        self._start()
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 377, in _start
        self.lib('general')   # assumed loaded by misc/constants.py
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 703, in lib
        self.eval('LIB "%s"'%lib)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/singular.py", line 546, in eval
        s = Expect.eval(self, x, **kwds)
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 983, in eval
        return '\n'.join([self._eval_line(L, **kwds) for L in code.split('\n') if L != ''])
      File "/home/leif/Sage/sage-4.5.3/local/lib/python/site-packages/sage/interfaces/expect.py", line 668, in _eval_line
        raise RuntimeError, "%s\n%s crashed executing %s"%(msg,self, line)
    RuntimeError: End Of File (EOF) in read_nonblocking(). Exception style platform.
    <pexpect.spawn instance at 0xaf32c0c>
    version: 2.0 ($Revision: 1.151 $)
    command: /home/leif/Sage/sage-4.5.3/local/bin/Singular
    args: ['/home/leif/Sage/sage-4.5.3/local/bin/Singular', '-t', '--ticks-per-sec', '1000']
    patterns:

    > 
    buffer (last 100 chars): 
    before (last 100 chars): mmand(a), continue(c) or quit Singular(q) ?fatal flex scanner internal error--end of buffer missed

    after: <class 'pexpect.EOF'>
    match: None
    match_index: None
    exitstatus: None
    flag_eof: 1
    pid: 26203
    child_fd: 4
    timeout: None
    delimiter: <class 'pexpect.EOF'>
    logfile: None
    maxread: 1000
    searchwindowsize: None
    delaybeforesend: 0
    Singular crashed executing LIB "general.lib";
**********************************************************************
File "/home/leif/Sage/sage-4.5.3/devel/sage-main/sage/rings/polynomial/multi_polynomial_element.py", line 1514:
    sage: M
Exception raised:
    Traceback (most recent call last):
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_49[6]>", line 1, in <module>
        M###line 1514:
    sage: M
    NameError: name 'M' is not defined
**********************************************************************
File "/home/leif/Sage/sage-4.5.3/devel/sage-main/sage/rings/polynomial/multi_polynomial_element.py", line 1516:
    sage: sum( map( mul , zip( M, I.gens() ) ) ) == f
Exception raised:
    Traceback (most recent call last):
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1231, in run_one_test
        self.run_one_example(test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/sagedoctest.py", line 38, in run_one_example
        OrigDocTestRunner.run_one_example(self, test, example, filename, compileflags)
      File "/home/leif/Sage/sage-4.5.3/local/bin/ncadoctest.py", line 1172, in run_one_example
        compileflags, 1) in test.globs
      File "<doctest __main__.example_49[7]>", line 1, in <module>
        sum( map( mul , zip( M, I.gens() ) ) ) == f###line 1516:
    sage: sum( map( mul , zip( M, I.gens() ) ) ) == f
    NameError: name 'M' is not defined
**********************************************************************
File "/home/leif/Sage/sage-4.5.3/devel/sage-main/sage/rings/polynomial/multi_polynomial_element.py", line 1570:
    sage: f.quo_rem(x)
Expected:
    (x*y + 1.00000000000000, 1.00000000000000)
Got:
    Singular crashed -- automatically restarting.
    (x*y + 1.00000000000000, 1.00000000000000)
**********************************************************************
2 items had failures:
   3 of   8 in __main__.example_49
   1 of   5 in __main__.example_51
***Test Failed*** 4 failures.
For whitespace errors, see the file /home/leif/.sage//tmp/.doctest_multi_polynomial_element.py
     [45.9 s]

It's not that clear if the error is caused by Singular, pexpect or Sage's Singular interface (or even the operating system, Ubuntu 7.10, kernel 2.6.22-16-generic).

[83660e46-0051-498b-a8c1-f7a7bd232b5a]

comment:10

P.S.: Both doctesting just these files and also make testlong passed without errors.

I wonder if read_nonblocking() is the right thing to do... (One can use signals to implement timeouts if that's the reason. I haven't looked at the code.)

[fchapoton]

Description changed:

--- 
+++ 
@@ -125,7 +125,7 @@
    1 of  16 in __main__.example_71
 ***Test Failed*** 3 failures.
 For whitespace errors, see the file /home/alex/.sage//tmp/.doctest_free_module.py
-    [13.0 s]
+ [13.0 s]

Minh Nguyen reports seeing the same error a GCC compile farm Debian 5.0 machine (gcc100.fsffrance.org, AMD Opteron(tm) Processor 252 @ 2647.708 MHz) with a trial "final" 4.5.3 (essentially the same as 4.5.3.rc0). Here is the test log.

[jdemeyer]

Reviewer: Jeroen Demeyer

[jdemeyer]

comment:18

I think this should be fixed in the mean time.