Hi all. Several months ago I opened an issue on the PySCIPOpt repo containing an example where PySCIPOpt 4.2 (running SCIP 8) incorrectly claimed that a small SOCP was infeasible. Since the issue has seen no activity over there and it probably belongs here, I'm posting just to make sure the SCIP devs are aware.

The relevant issue is: https://github.com/scipopt/PySCIPOpt/issues/583.

Ping @BrannonKing, since he might be interested in this getting resolved.

When trying to compile SCIP from source, the build fails with

error: cannot convert ‘void(void*, unsigned int, const unsigned int*)’ to ‘const std::function<void(unsigned int, const unsigned int*)>&

in https://github.com/scipopt/scip/blob/07dfd86f87f15f8d31eee700f603283bfb6ab357/src/symmetry/compute_symmetry_bliss.cpp#L1087

I looked up the reference, seems like Bliss has changed the signature (user_param is no longer accepted as a param), Is SCIP using a forked version of the API?

I was able to surpass the error by rewriting the blisshook to

    auto blisshook = [&data](
      unsigned int          n,                  /**< size of aut vector */
      const unsigned int*   aut                 /**< automorphism */
      )
    {
      assert( aut != NULL );

      assert( data.scip != NULL );
      assert( data.npermvars < (int) n );
      assert( data.maxgenerators >= 0);

      /* make sure we do not generate more that maxgenerators many permutations, if the limit in bliss is not available */
      if ( data.maxgenerators != 0 && data.nperms >= data.maxgenerators )
          return;

      /* copy first part of automorphism */
      bool isIdentity = true;
      int* p = 0;
      if ( SCIPallocBlockMemoryArray(data.scip, &p, data.npermvars) != SCIP_OKAY )
          return;

      for (int j = 0; j < data.npermvars; ++j)
      {
          /* convert index of variable-level 0-nodes to variable indices */
          p[j] = (int) aut[j];
          if ( p[j] != j )
            isIdentity = false;
      }

      /* ignore trivial generators, i.e. generators that only permute the constraints */
      if ( isIdentity )
      {
          SCIPfreeBlockMemoryArray(data.scip, &p, data.npermvars);
          return;
      }

      /* check whether we should allocate space for perms */
      if ( data.nmaxperms <= 0 )
      {
          if ( data.maxgenerators == 0 )
            data.nmaxperms = 100;   /* seems to cover many cases */
          else
            data.nmaxperms = data.maxgenerators;

          if ( SCIPallocBlockMemoryArray(data.scip, &data.perms, data.nmaxperms) != SCIP_OKAY )
            return;
      }
      else if ( data.nperms >= data.nmaxperms )    /* check whether we need to resize */
      {
          int newsize = SCIPcalcMemGrowSize(data.scip, data.nperms + 1);
          assert( newsize >= data.nperms );
          assert( data.maxgenerators == 0 );

          if ( SCIPreallocBlockMemoryArray(data.scip, &data.perms, data.nmaxperms, newsize) != SCIP_OKAY )
            return;

          data.nmaxperms = newsize;
      }

      data.perms[data.nperms++] = p;
    };

and the call to

   G.find_automorphisms(stats, blisshook);

It is now working as expected, if you think that's a correct fix, I can prepare a patch :).

Thanks.

When trying to build SCIP in our Vagrant generic/FreeBSD13 box (note a FreeBSD VirtualBox img) we are facing some compilation issue...

Observed

here the relevant trace (please notice we are building SCIP using FetchContent from our or-tools CMake based build)

default: [ 48%] Building CXX object _deps/scip-build/src/CMakeFiles/libscip.dir/amplmp/src/os.cpp.o
    default: cd /usr/home/vagrant/project/build/_deps/scip-build/src && /usr/bin/c++  -I/usr/home/vagrant/project/build/_deps/scip-src/src/amplmp/include -I/usr/home/vagrant/project/build/_deps/scip-build -I/usr/home/vagrant/project/build/_deps/scip-src/src -I/usr/home/vagrant/project/build/_deps/zlib-build -I/usr/home/vagrant/project/build/_deps/zlib-src -O3 -DNDEBUG -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -std=c++14 -MD -MT _deps/scip-build/src/CMakeFiles/libscip.dir/amplmp/src/os.cpp.o -MF CMakeFiles/libscip.dir/amplmp/src/os.cpp.o.d -o CMakeFiles/libscip.dir/amplmp/src/os.cpp.o -c /usr/home/vagrant/project/build/_deps/scip-src/src/amplmp/src/os.cpp
    default: /usr/home/vagrant/project/build/_deps/scip-src/src/amplmp/src/os.cpp:108:4: error: GetExecutablePath is not implemented for this system
    default: #  error GetExecutablePath is not implemented for this system
    default:    ^
    default: 1 error generated.
    default: *** Error code 1
    default: 
    default: Stop.
    default: make[2]: stopped in /usr/home/vagrant/project/build
    default: *** Error code 1
    default: 
    default: Stop.
    default: make[1]: stopped in /usr/home/vagrant/project/build
    default: *** Error code 1
    default: 
    default: Stop.
    default: make: stopped in /usr/home/vagrant/project/build
The SSH command responded with a non-zero exit status. Vagrant
assumes that this means the command failed. The output for this command
should be in the log above. Please read the output to determine what
went wrong.

ref: https://github.com/google/or-tools/runs/3672547012?check_suite_focus=true

https://github.com/scipopt/scip/blob/9444e80869f6ac42723f3a43712ca6d4ce0c20dc/src/amplmp/src/os.cpp#L107-L109

Expected

Have support of FreeBSD so we can use it in OR-Tools or at least a dummy function instead of this error message breaking the build ;) Also it seems that amplmp is only use to read some .nl file so it's sad to break the build for this "optional" feature... https://github.com/scipopt/scip/blob/9444e80869f6ac42723f3a43712ca6d4ce0c20dc/src/amplmp/README#L2

Annexe

You can found our Vagrantfile here: https://github.com/google/or-tools/blob/master/cmake/vagrant/freebsd/cpp/Vagrantfile

note: I think it should be easy to adapt it to only build SCIP starting from your repo to get rid of or-tools shenanigan and/or add it as a CI job to this repo (if you are willing to use github action workflow) ;)

Hello Team,

I apologize if this is not the best place to post this request for help; having spent a few days trying to read documentation and figure out what to do. I need to get the entire search tree used during computation of a solution to an LP. This tree I assume would have unexplored nodes, pruned nodes etc. Is this possible on SCIP? Thanks for your help and guidance.

I compiled SCIP 7.0.3 on Mac and I am coding on C++.

Hello!

I came across a nasty issue when trying to solve a model from an LP file.
As far as I can tell, the SCIPOPT LP parser follows the LP specification of CPLEX:

• https://www.scipopt.org/doc-7.0.3/html/reader__lp_8h.php
• https://www.ibm.com/docs/en/icos/12.9.0?topic=cplex-lp-file-format-algebraic-representation

From testing, I do know (now) that CPLEX does not support constant values within the constraint expressions. The specification itself does not explicitly state this:

• "The constraints are entered in the same way as the objective function".
• Objective expressions support constants in the (objective-) expression

This is not the nicest definition, but something that can be worked with.

Problem description

If CPLEX is presented with an LP file that violates this rule, an error is raised:

invalid.lp

\none
Maximize
 var_x 
Subject To
 var_x - 1 = 0
Bounds
 1 <= var_x <= 1
Binary
 var_x
End

CPLEX output

CPLEX> read invalid.lp
CPLEX Error  1616: Line 5: Expected identifier, found '='.
No file read.
CPLEX>

If the same LP is given to SCIPOPT, it is read without error, and solved: SCIPOPT output

SCIP> read C:\temp\scip\invalid.lp

read problem <C:\temp\scip\invalid.lp>
============

original problem has 1 variables (1 bin, 0 int, 0 impl, 0 cont) and 1 constraints
SCIP> optimize

presolving:
presolving (1 rounds: 1 fast, 0 medium, 0 exhaustive):
 1 deleted vars, 0 deleted constraints, 0 added constraints, 0 tightened bounds, 0 added holes, 0 changed sides, 0 changed coefficients
 0 implications, 0 cliques
presolving detected infeasibility
Presolving Time: 0.00

SCIP Status        : problem is solved [infeasible]
Solving Time (sec) : 0.00
Solving Nodes      : 0
Primal Bound       : -1.00000000000000e+20 (objective limit, 0 solutions)
Dual Bound         : +1.00000000000000e+20
Gap                : 0.00 %

SCIP simply omits the constant in the constraint expression, and solves the (inconsistent) problem. In this case, the model becomes infeasible by omitting the constant. However, with a slight adjustment to the LB of var_x, the model will become feasible and the result will deviate from the intended/expected solution:

feasible_invalid.lp

\none
Maximize
 var_x 
Subject To
 var_x - 1 = 0
Bounds
 0 <= var_x <= 1
Binary
 var_x
End

SCIP output (var_x LB = 0)

SCIP> read C:\temp\scip\feasible_invalid.lp

read problem <C:\temp\scip\feasible_invalid.lp>
============

original problem has 1 variables (1 bin, 0 int, 0 impl, 0 cont) and 1 constraints
SCIP> optimize

feasible solution found by trivial heuristic after 0.0 seconds, objective value 0.000000e+00
presolving:
presolving (1 rounds: 1 fast, 0 medium, 0 exhaustive):
 1 deleted vars, 0 deleted constraints, 0 added constraints, 1 tightened bounds, 0 added holes, 0 changed sides, 0 changed coefficients
 0 implications, 0 cliques
Presolving Time: 0.00

SCIP Status        : problem is solved [optimal solution found]
Solving Time (sec) : 0.00
Solving Nodes      : 0
Primal Bound       : +0.00000000000000e+00 (1 solutions)
Dual Bound         : +0.00000000000000e+00
Gap                : 0.00 %

If the same file is parsed + solved with, e.g., Gurobi (which supports constants in constraint expressions), the following output is produced: Gurobi output

gurobi> m = read('feasible_invalid.lp')
Read LP format model from file feasible_invalid.lp
Reading time = 0.00 seconds
: 1 rows, 2 columns, 2 nonzeros
gurobi> m.optimize()
Gurobi Optimizer version 9.5.0 build v9.5.0rc5 (win64)
Thread count: 4 physical cores, 4 logical processors, using up to 4 threads
Optimize a model with 1 rows, 2 columns and 2 nonzeros
Model fingerprint: 0xf7308cbe
Variable types: 1 continuous, 1 integer (1 binary)
Coefficient statistics:
  Matrix range     [1e+00, 1e+00]
  Objective range  [1e+00, 1e+00]
  Bounds range     [1e+00, 1e+00]
  RHS range        [0e+00, 0e+00]
Found heuristic solution: objective -0.0000000
Presolve removed 1 rows and 2 columns
Presolve time: 0.00s
Presolve: All rows and columns removed

Explored 0 nodes (0 simplex iterations) in 0.00 seconds (0.00 work units)
Thread count was 1 (of 4 available processors)

Solution count 2: 1 -0

Optimal solution found (tolerance 1.00e-04)
Best objective 1.000000000000e+00, best bound 1.000000000000e+00, gap 0.0000%
gurobi>

Expected behavior

• Main priority
  • Given the current LP file format specification that SCIPOPT is following, I'd expect an error message when an invalid LP file is given. The silent fail might cause serious issues, since the resulting model might actually be feasible - but the solution differs from the "intended" model.
• Nice to have
  • Add support for constant values in constraints, similar to Gurobi's LP file format

I hope this is the correct address for reporting such an issue. If this is not the case, please let me know where I can/should submit it.

Best Regards,
Jannick

Good afternoon.

I have created an example model where SCIP finds an optimal solution, but if certain constraints are removed, SCIP claims the model is infeasible.

With these constraints (plus some bound constraints):

We get this optimal solution:

And simply deleting the temperature constraints:

We get an infeasible model:

Maybe I am not thinking clearly, but it seems that this should not happen. You can see the code here: incorrect_infeasibility.zip.

Merry Christmas, I am looking into SCIP for a research project and was wondering whether there is a specific reason why certain heuristic parameters are only exposed by getter methods in the public API. This PR includes an example. The option of setting consistent heuristic parameters would be useful for me (like implemented with SCIPheurSetFreq). Best regards, Anton Hinneck

I have 2 questions:

1. Is it possible to remove a node from the node pool during the solving process safely? I want to remove a subtree from the solving process.
2. If so, is it possible to do that in fscip? Since fscip is a parallel version of scip, should I use some mutex/lock to accomplish this?

Thanks.

Hi, I found bug on SCIP concurrentopt function. I compiled IPOPT with HSL libraries contains HSL_MA97 which use OpenMP for parallel computation. I configure SCIP to use HSL_MA97 via command "set nlpi ipopt linear_solver ma97". When I try to start concurrentopt fails. I think, this problem hard to fix but some explanation can be added for wrong settings. Thanks for for your hard work.

/usr/local/bin/ld: ../bin/scip: hidden symbol `xlp_conname_exists' in CMakeFiles/scip.dir/scip/reader_zpl.c.o is referenced by DSO
/usr/local/bin/ld: final link failed: bad value
c++: error: linker command failed with exit code 1 (use -v to see invocation)
*** [bin/scip] Error code 1

It appears that the cause is that xlp_conname_exists is defined in both SCIP and ZIMPL projects.

OS: FreeBSD 13 clang-11

TLDR: It seems the SCIP source depends on M_PI which is a GNU extension, i.e. compiling using -std=c99 won't work.

Protocol

If here: https://github.com/scipopt/scip/blob/a6142b7d1d7892f950b1e5127925f7c435151beb/src/CMakeLists.txt#L10-L12 I'm adding the line

set(CMAKE_C_EXTENSIONS OFF)

Then CMake will generate compile line using -std=c99 instead of the "default" -std=gnu99

ref: https://cmake.org/cmake/help/latest/variable/CMAKE_CXX_EXTENSIONS.html note: You can also pass it on CMake configure line or could be given by a super project integrating SCIP from sources... note2: Usually CMake default enable extensions seems to have change 17months ago see https://github.com/Kitware/CMake/commit/f034b0f66338f37d4f637916cc42b9c4a4f30a32

Observed

note: I'm doing some integration tests of multithread SCIP so technically I building SCIP using through FetchContent() full project here: https://github.com/Mizux/scip-multithread

cmake --build build -v
...
[ 17%] Building C object _deps/scip-build/src/CMakeFiles/libscip.dir/scip/cons_soc.c.o
cd /home/mizux/dev/scip-multithread/build/_deps/scip-build/src && /usr/bin/clang
 -I/home/mizux/dev/scip-multithread/build/_deps/scip-build
 -I/home/mizux/dev/scip-multithread/build/_deps/scip-src/src
 -I/home/mizux/dev/scip-multithread/build/_deps/zlib-build
 -I/home/mizux/dev/scip-multithread/build/_deps/zlib-src
 -fsanitize=thread -g -fPIC -fvisibility=hidden -std=c99 # SEE HERE the use of -std=c99
 -MD -MT
 _deps/scip-build/src/CMakeFiles/libscip.dir/scip/cons_soc.c.o
 -MF CMakeFiles/libscip.dir/scip/cons_soc.c.o.d
 -o CMakeFiles/libscip.dir/scip/cons_soc.c.o
 -c /home/mizux/dev/scip-multithread/build/_deps/scip-src/src/scip/cons_soc.c
/home/mizux/dev/scip-multithread/build/_deps/scip-src/src/scip/cons_soc.c:1996:10: error: use of undeclared identifier 'M_PI'
   val = M_PI;
         ^
/home/mizux/dev/scip-multithread/build/_deps/scip-src/src/scip/cons_soc.c:2238:13: error: use of undeclared identifier 'M_PI'
      val = M_PI / pow(2.0, (double) (i+1));
            ^
/home/mizux/dev/scip-multithread/build/_deps/scip-src/src/scip/cons_soc.c:2313:19: error: use of undeclared identifier 'M_PI'
   vals[0] = tan( M_PI / pow(2.0, (double) (N+1)) );
                  ^
3 errors generated.
make[2]: *** [_deps/scip-build/src/CMakeFiles/libscip.dir/build.make:776: _deps/scip-build/src/CMakeFiles/libscip.dir/scip/cons_soc.c.o] Error 1
make[2]: Leaving directory '/home/mizux/dev/scip-multithread/build'
make[1]: *** [CMakeFiles/Makefile2:1057: _deps/scip-build/src/CMakeFiles/libscip.dir/all] Error 2
make[1]: Leaving directory '/home/mizux/dev/scip-multithread/build'
make: *** [Makefile:166: all] Error 2

note: I tweaked the indent of the trace fun fact: PI only officially exist since C++20 (https://en.cppreference.com/w/cpp/numeric/constants)

Proposal

If i were you:

1. I would be explicit, because in case of a super project build integrating scip with this option to OFF it will fail. Ie since it seems mandatory you should force it -> set(CMAKE_C_EXTENSIONS ON)
2. add a define in case...

   #ifndef M_PI
   #define M_PI 3.14159265358979323846
   #endif
   

Platform

FYI

%uname -a
Linux nuc10i7 5.13.5-arch1-1 #1 SMP PREEMPT Sun, 25 Jul 2021 18:02:58 +0000 x86_64 GNU/Linux
%gcc --version
gcc (GCC) 11.1.0
% clang --version
clang version 12.0.1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

I've been studying nlhdlr_quadratic.c to understand how to iterate the extreme rays when at an optimum of the LP relaxation. It's more complex than expected. (It might be less complex if the code for handling quadratics was not part of it.) Is it possible to expose some public methods for iterating the extreme rays of an optimal corner? This is surely a common need for modern cutting techniques, no?

In the meantime, can you give some guidance on iterating extreme rays of the corner in a custom separator for MILP problems?

Building a certain MILP with indicator constraints produces the following the lines of error and causes the program to crash:

ELEAVE56 ERROR! Tried to put a fixed column variable into the basis. idx=72, lower=0, upper=0
ELEAVE56 ERROR! Tried to put a fixed column variable into the basis. idx=72, lower=0, upper=0
ELEAVE56 ERROR! Tried to put a fixed column variable into the basis. idx=79, lower=0, upper=0

The underlying issue was introduced between scip version 8.0.0 to 8.0.1 (scip 8.0.0 solves the problem correctly, scip 8.0.1 produces the error).

I use pyscipopt in python 3.7 to construct the problem. Both, version 4.2.0 and 4.0.0 work fine.

Here the "writeProblem" output (identical for scip 8.0.0 and 8.0.1):

\ SCIP STATISTICS
\   Problem name     : model
\   Variables        : 112 (26 binary, 0 integer, 0 implicit integer, 86 continuous)
\   Constraints      : 123
Minimize
 Obj: +1 x1 +0.6 x3 +1.1 x4 +0.75 x5 +1 x6 +0.8 x7 +1 x8 +1 x9 +1 x11 +1.5 x13 +1.2 x15
Subject to
 c1: -1 x1 -0.6 x3 -1.1 x4 -0.75 x5 -1 x6 -0.8 x7 -1 x8 -1 x9 -1 x11 -1.5 x13 -1.2 x15 <= +0
 c2: +1 x1 +0.6 x3 +1.1 x4 +0.75 x5 +1 x6 +0.8 x7 +1 x8 +1 x9 +1 x11 +1.5 x13 +1.2 x15 <= +4
 c4: +1 x16 -1 x18 +1 x30 -1 x47 <= +0
 c5: -1 x16 +0.4 x28 +1 x29 -1 x55 <= +0
 c6: +1 x21 +1 x27 -1 x57 <= +0
 c7: +1 x23 +1 x31 <= +0
 c8: +1 x27 -1 x33 <= +0
 c9: +4.5 x27 -1 x43 <= +0
 c10: +1 x24 -100 x27 <= +0
 c11: +1 x25 -100 x27 <= +0
 c12: -100 x27 +1 x32 <= +0
 c13: -100 x27 +1 x33 <= +0
 c14: -100 x27 +1 x34 <= +0
 c15: -1 x24 -100 x27 <= +0
 c16: -100 x27 +1 x35 <= +0
 c17: -100 x27 +1 x36 <= +0
 c18: -1 x25 -100 x27 <= +0
 c19: -100 x27 +1 x37 <= +0
 c20: -100 x27 +1 x38 <= +0
 c21: -10 x27 +1 x39 <= +0
 c22: -100 x27 +1 x40 <= +0
 c23: -100 x27 +1 x41 <= +0
 c24: -100 x27 +1 x42 <= +0
 c25: -0.1 x29 -1 x30 -4.5 x31 -1 x41 +100 x44 +100 x45 +100 x46 +100 x47 +100 x48 +100 x49 +100 x50 +100 x51
  +100 x52 +100 x53 +100 x54 +10 x55 +100 x56 +100 x57 +100 x58 <= -1
 c26: +1 x23 <= +0
 c27: +1 x59 +9 x1 <= +9
 c28: +1 x61 -4.9 x3 <= +0
 c29: +1 x62 +10 x4 <= +10
 c30: +1 x63 +10 x5 <= +10
 c31: +1 x64 -10 x6 <= +0
 c32: +1 x65 +9 x7 <= +9
 c33: +1 x66 +9 x8 <= +9
 c34: +1 x67 +5 x9 <= +5
 c35: +1 x69 +9 x11 <= +9
 c36: +1 x71 +9.8 x13 <= +9.8
 c37: -1 x62 +4.9 x4 <= +4.9
 c38: -1 x65 +10 x7 <= +10
 c39: -1 x73 +5.5 x15 <= +5.5
 c40: +1 x32 +1 x33 +1 x34 +1 x37 -1 x39 = +0
 c41: -1 x25 -1 x32 +1 x36 +1 x38 = +0
 c42: -1 x33 +1 x34 +1 x35 +1 x36 +1 x38 = +0
 c43: +1 x24 -1 x34 +1 x35 = +0
 c44: +1 x25 -1 x36 -1 x37 +1 x40 = +0
 c45: -1 x35 -1 x36 -1 x38 +1 x41 = +0
 c46: -1 x24 -1 x34 -1 x35 -1 x38 +1 x42 = +0
 c47: +1 x26 -1 x36 +1 x43 = +0
 c48: -1 x59 -1 x60 -1 x61 -1 x66 +1 x68 = +0
 c49: +1 x59 -1 x64 -1 x65 -1 x67 = +0
 c50: +1 x60 -1 x61 -1 x63 -1 x64 -1 x67 = +0
 c51: +1 x61 +1 x62 -1 x63 = +0
 c52: +1 x64 +1 x65 +1 x66 -1 x69 = +0
 c53: +1 x63 +1 x64 +1 x67 -1 x70 = +0
 c54: +1 x61 -1 x62 +1 x63 +1 x67 -1 x71 = +0
 c55: +1 x64 -1 x72 +1 x73 = +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x1>[B],<x74>[B]) = 1;
 IndicatorCons: x74 = 1 ->  +1 x16 -1 x17 -1 x46 <= +0
 IndicatorCons: x3 = 1 ->  +1 x16 +1 x18 -1 x19 -1 x22 -1 x48 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x5>[B],<x77>[B]) = 1;
 IndicatorCons: x77 = 1 ->  +1 x18 +1 x19 -1 x21 -1 x22 -1 x50 <= +0
 IndicatorCons: x6 = 1 ->  +1 x17 +1 x18 -1 x20 -1 x21 -1 x23 -1 x51 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x8>[B],<x80>[B]) = 1;
 IndicatorCons: x80 = 1 ->  +1 x16 -1 x20 -1 x53 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x9>[B],<x82>[B]) = 1;
 IndicatorCons: x82 = 1 ->  +1 x17 +1 x18 -1 x21 -1 x22 -1 x54 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x11>[B],<x84>[B]) = 1;
 IndicatorCons: x84 = 1 ->  +1 x20 -1 x28 -1 x56 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x13>[B],<x86>[B]) = 1;
 IndicatorCons: x86 = 1 ->  +1 x22 -1 x58 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x15>[B],<x88>[B]) = 1;
 IndicatorCons: x88 = 1 ->  -1 x23 <= +0
 IndicatorCons: x1 = 1 ->  +1 x32 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x3>[B],<x91>[B]) = 1;
 IndicatorCons: x91 = 1 ->  +1 x34 <= +0
 IndicatorCons: x5 = 1 ->  +1 x35 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x6>[B],<x94>[B]) = 1;
 IndicatorCons: x94 = 1 ->  +1 x36 <= +0
 IndicatorCons: x8 = 1 ->  +1 x37 <= +0
 IndicatorCons: x9 = 1 ->  +1 x38 <= +0
 IndicatorCons: x11 = 1 ->  +1 x40 <= +0
 IndicatorCons: x13 = 1 ->  +1 x42 <= +0
 IndicatorCons: x15 = 1 ->  +1 x73 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x4>[B],<x101>[B]) = 1;
 IndicatorCons: x101 = 1 ->  +1 x19 -1 x22 -1 x44 +1 x49 <= +0
 IndicatorCons: x101 = 1 ->  -1 x19 +1 x22 +1 x44 -1 x49 <= +0
constraint handler <xor> cannot print requested format
\   [xor] <XORcons>: xor(<x7>[B],<x104>[B]) = 1;
 IndicatorCons: x104 = 1 ->  -1 x17 +1 x20 -1 x45 +1 x52 <= +0
 IndicatorCons: x104 = 1 ->  +1 x17 -1 x20 +1 x45 -1 x52 <= +0
 IndicatorCons: x4 = 1 ->  +1 x24 <= +0
 IndicatorCons: x4 = 1 ->  -1 x24 <= +0
 IndicatorCons: x7 = 1 ->  +1 x25 <= +0
 IndicatorCons: x7 = 1 ->  -1 x25 <= +0
 IndicatorCons: x15 = 1 ->  +1 x26 <= +0
 IndicatorCons: x15 = 1 ->  -1 x26 <= +0
Bounds
 0 <= x1 <= 1
 0 <= x2 <= 0
 0 <= x3 <= 1
 0 <= x4 <= 1
 0 <= x5 <= 1
 0 <= x6 <= 1
 0 <= x7 <= 1
 0 <= x8 <= 1
 0 <= x9 <= 1
 0 <= x10 <= 0
 0 <= x11 <= 1
 0 <= x12 <= 0
 0 <= x13 <= 1
 0 <= x14 <= 0
 0 <= x15 <= 1
 0 <= x74 <= 1
 0 <= x77 <= 1
 0 <= x80 <= 1
 0 <= x82 <= 1
 0 <= x84 <= 1
 0 <= x86 <= 1
 0 <= x88 <= 1
 0 <= x91 <= 1
 0 <= x94 <= 1
 0 <= x101 <= 1
 0 <= x104 <= 1
 x27 free
 0 <= x59 <= 100
 1 <= x60 <= 100
 0 <= x61 <= 100
 -100 <= x62 <= 100
 0 <= x63 <= 100
 0 <= x64 <= 100
 -100 <= x65 <= 100
 0 <= x66 <= 100
 0 <= x67 <= 100
 0 <= x68 <= 10
 0 <= x69 <= 100
 0.2 <= x70 <= 100
 0 <= x71 <= 100
 4.5 <= x72
 x73 free
 x16 free
 x17 free
 x18 free
 x19 free
 x20 free
 x21 free
 x22 free
 x23 free
 x24 free
 x25 free
 x26 free
Binaries
 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15 x74 x77 x80 x82 x84 x86 x88 x91 x94 x101 x104
End

Mr Matthias suggested me to create an issue here. I understand that there has have already been a huge amount of issues that have been resolved with regards to installation, but something seems to be going haywire in my installation process and I am very keen to understand why and how to resolve it. Please, if you could see the my doings below.

On downloading scip-8.0.0 from the official website, and following the commands listed here: https://github.com/scipopt/scip/blob/master/INSTALL.md. I get a weird error:

-- Build shared libraries: ON
-- Build type: Release
-- Finding ZLIB
-- Finding ZLIB - found
-- Finding Readline
-- Finding Readline - found
-- Finding GMP
-- Finding GMP - found
-- Finding PAPILO
CMake Error at CMakeLists.txt:298 (find_package):
Could not find a package configuration file provided by "PAPILO" with any
of the following names:

PAPILOConfig.cmake
papilo-config.cmake
Add the installation prefix of "PAPILO" to CMAKE_PREFIX_PATH or set
"PAPILO_DIR" to a directory containing one of the above files. If "PAPILO"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!

I was wondering if you could please help me resolve this?

Many thanks for your time on this.

• scip-8.0.0

make install output :

//usr/local/lib/libreadline.so.8: undefined reference to tgetstr' //usr/local/lib/libreadline.so.8: undefined reference totputs' //usr/local/lib/libreadline.so.8: undefined reference to BC' //usr/local/lib/libreadline.so.8: undefined reference totgetent' //usr/local/lib/libreadline.so.8: undefined reference to tgetflag' //usr/local/lib/libreadline.so.8: undefined reference totgoto' //usr/local/lib/libreadline.so.8: undefined reference to UP' //usr/local/lib/libreadline.so.8: undefined reference totgetnum' //usr/local/lib/libreadline.so.8: undefined reference to `PC' collect2: error: ld returned 1 exit status gcg/src/CMakeFiles/gcg.dir/build.make:2211: recipe for target 'bin/gcg' failed make[2]: *** [bin/gcg] Error 1 CMakeFiles/Makefile2:2954: recipe for target 'gcg/src/CMakeFiles/gcg.dir/all' failed make[1]: *** [gcg/src/CMakeFiles/gcg.dir/all] Error 2 Makefile:165: recipe for target 'all' failed make: *** [all] Error 2