Opened 3 years ago
Closed 3 years ago
#20326 closed defect (fixed)
GenericBackend: Fix doctest of add_linear_constraint_vector
Reported by:  mkoeppe  Owned by:  

Priority:  major  Milestone:  sage7.2 
Component:  numerical  Keywords:  lp 
Cc:  dimpase, vdelecroix  Merged in:  
Authors:  Matthias Koeppe  Reviewers:  Dima Pasechnik 
Report Upstream:  N/A  Work issues:  
Branch:  690b1a5 (Commits)  Commit:  690b1a55435f70abfd17bfcc752af13a7cce8e52 
Dependencies:  Stopgaps: 
Description (last modified by )
The doctest of add_linear_constraint_vector
from generic_backend.pyx (which is never run for any real backend!), when applied to COIN or GLPK leads to segfaults:
sage: coeffs = ([0, vector([1, 2])], [1, vector([2, 3])]) sage: upper = vector([5, 5]) sage: lower = vector([0, 0]) sage: from sage.numerical.backends.generic_backend import get_solver sage: p = get_solver(solver = "Coin") # optional  cbc sage: p.add_linear_constraint_vector(2, coeffs, lower, upper, 'foo')  0 signals.so 0x0000000109df05c5 print_backtrace + 37  Unhandled SIGSEGV: A segmentation fault occurred. This probably occurred because a *compiled* module has a bug in it and is not properly wrapped with sig_on(), sig_off(). Python will now terminate.  Segmentation fault: 11 $ sage SageMath Version 7.2.beta0, Release Date: 20160324 sage: coeffs = ([0, vector([1, 2])], [1, vector([2, 3])]) sage: upper = vector([5, 5]) sage: lower = vector([0, 0]) sage: from sage.numerical.backends.generic_backend import get_solver sage: p = get_solver(solver = "Coin") # optional  cbc sage: p.add_linear_constraint_vector(2, coeffs, lower, upper)  0 signals.so 0x0000000109c8a5c5 print_backtrace + 37  Unhandled SIGSEGV: A segmentation fault occurred.
Change History (14)
comment:1 Changed 3 years ago by
 Description modified (diff)
comment:2 Changed 3 years ago by
The COIN segfaults are addressed in #20360.
comment:3 Changed 3 years ago by
 Branch set to u/mkoeppe/genericbackend__fix_doctest_of_add_linear_constraint_vector
comment:4 Changed 3 years ago by
 Cc ncohen removed
 Commit set to dea0705ca3ff339dc7887ae040c1c787d03798a0
 Status changed from new to needs_review
New commits:
dea0705  Fix #20326: GenericBackend: Fix doctest of add_linear_constraint_vector

comment:5 Changed 3 years ago by
solver.add_variables(2)
throws a NotImplementedError
immediately, what's the point of the last commit then?
sage t src/sage/numerical/backends/generic_backend.pyx ********************************************************************** File "src/sage/numerical/backends/generic_backend.pyx", line 402, in sage.numerical.backends.generic_backend.GenericBackend.add_linear_constraint_vector Failed example: solver.add_variables(2) ... NotImplementedError
comment:6 Changed 3 years ago by
if you want to keep these as a template you'd mark them # not tested
comment:7 Changed 3 years ago by
 Commit changed from dea0705ca3ff339dc7887ae040c1c787d03798a0 to b932b890e06615af0d8501127e6dbcfb49c4dff3
Branch pushed to git repo; I updated commit sha1. New commits:
b932b89  add_linear_constraint_vector: Fix fix of doctest

comment:8 Changed 3 years ago by
Sorry! I tested the wrong file after making this change, so I did not catch this test failure.
Yes, the idea is to make generic_backend.pyx
suitable for cut and paste again.
But don't worry, I won't make many more tickets like this one; I have been making progress with #20323.
comment:9 followup: ↓ 11 Changed 3 years ago by
Isn't it more in line with the rest of the code to tag these statements by # optional  Nonexistent_LP_solver
? Then you don't need to insert Tracebacks...
comment:10 Changed 3 years ago by
 Commit changed from b932b890e06615af0d8501127e6dbcfb49c4dff3 to 690b1a55435f70abfd17bfcc752af13a7cce8e52
comment:11 in reply to: ↑ 9 Changed 3 years ago by
Replying to dimpase:
Isn't it more in line with the rest of the code to tag these statements by
# optional  Nonexistent_LP_solver
? Then you don't need to insert Tracebacks...
You are right. I have now brought it in line with the doctests for the other methods. Same also for add_linear_constraint
.
comment:13 Changed 3 years ago by
 Reviewers set to Dima Pasechnik
comment:14 Changed 3 years ago by
 Branch changed from u/mkoeppe/genericbackend__fix_doctest_of_add_linear_constraint_vector to 690b1a55435f70abfd17bfcc752af13a7cce8e52
 Resolution set to fixed
 Status changed from positive_review to closed
with the second example I only get segfault with Coin  with other backends I get gracefully handled errors. (on a branch with lots of recent positively reviewed LPrelated tickets)