Terminate called by json library

[mwetz]

When running gamspy for different optimization problems the log file reports the following error, which then also triggers a core dump, while the process seems to continue running:

terminate called after throwing an instance of 'nlohmann::json_abi_v3_11_2::detail::type_error'
  what():  [json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xA0

We also observed the error with indifferent optimization models. In the small model, the error is thrown while already in the external solver calls - in this case the process terminates with results. In the large model, the error is thrown while gamspy is still executing the temporary gms files. Here the process gets stuck and does no longer continue.

The following software stack was used: Rocky Linux 8.9 python 3.12.4 gamspy 0.13.5

[mabdullahsoyturk]

Is it possible to share your script?

[mwetz]

Since our script is in a more complex workflow we created a minimum example to reproduce the issue. The error occurs between 2-3 minutes into the run. The Windows machine was able to complete it, while the Linux machine got stuck again when calling the solver.

import sys
import gamspy as gp
import numpy as np

rng = np.random.default_rng(seed=0)

size = int(5e6)
rands = 1000 * rng.random(size=size)

ct = gp.Container()

S = ct.addSet("S", records=range(len(rands)))

p = ct.addParameter("p", [S], records=rands)
p[S] = 1
x = ct.addVariable("x", domain=S)

eq = ct.addEquation("eq", domain=S)
eq[S] = x[S] >= p[S]

obj = gp.Sum(S, x[S])

m = ct.addModel("m", gp.Problem.LP, [eq], gp.Sense.MIN, obj)
res = m.solve(output=sys.stdout)

[mwetz]

And here's the logfile:

--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  125 secs
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  130 secs
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  135 secs
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  140 secsterminate called after throwing an instance of 'nlohmann::json_abi_v3_11_2::detail::type_error'
  what():  [json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xB1

--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  145 secs
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  150 secs
[...]
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(41) 1839 Mb  235 secs
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1839 Mb
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1854 Mb
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1871 Mb
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1899 Mb
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1879 Mb
--- _5ee820bf-f61c-4734-be64-2f16aaac5447.gms(46) 1879 Mb  3 secs
---   5,000,001 rows  5,000,001 columns  10,000,001 non-zeroes
--- Range statistics (absolute non-zero finite values)
--- RHS       [min, max] : [ 1.000E+00, 1.000E+00] - Zero values observed as well
--- Bound     [min, max] : [        NA,        NA]
--- Matrix    [min, max] : [ 1.000E+00, 1.000E+00]
--- Executing CPLEX (Solvelink=2): elapsed 0:04:01.582

IBM ILOG CPLEX   47.3.0 125a0e22 Jul 15, 2024          LEG x86 64bit/Linux

[mabdullahsoyturk]

This should be fixed with the release of gamspy_base 47.4. Please reopen if you think the problem persists.

[mwetz]

Yes, confirmed - the instance now solves successfully. Thank you for the swift fix!