Error Installing PySCIPOpt on Mac OSX

Question

After installing SCIP Optimization Suite on OS X by compiling the source and installing Cython,

make
make install INSTALLDIR="/usr/local/"
make SHARED=true GMP=false READLINE=false scipoptlib
pip install Cython

the installation of PySCIPOpt was attempted

git clone https://github.com/SCIP-Interfaces/PySCIPOpt.git
cd PySCIPOpt
$ SCIPOPTDIR=./ python setup.py install

But this gave an error. Any suggestions?

Traceback (most recent call last):
File "setup.py", line 29, in <module>
scipsrcdir = sorted(scipsrcdir)[-1]  # use the latest version
IndexError: list index out of range

---

Problem importing library

After successfully installing pyscipopt , when the library is being imported using

from pyscipopt.scip import Model

I get the Library not loaded error

  File "test.py", line 1, in <module>
    from pyscipopt import Model
  File "/Users/test/anaconda/envs/test/lib/python2.7/site-packages/pyscipopt/__init__.py", line 3, in <module>
    from pyscipopt.scip      import Model
ImportError: dlopen(/Users/test/anaconda/envs/test/lib/python2.7/site-packages/pyscipopt/scip.so, 2): Library not loaded: lib/libscipopt-3.2.1.darwin.x86_64.gnu.opt.so
  Referenced from: /Users/test/anaconda/envs/test/lib/python2.7/site-packages/pyscipopt/scip.so
  Reason: image not found

After some searching, I tried someone's solution:

export DYLD_LIBRARY_PATH=/path/to/scipoptsuite-3.2.1/lib 

but running the Python file again gives a different error Symbol not found: _history_length

Traceback (most recent call last):
  File "test.py", line 1, in <module>
    from pyscipopt import Model
  File "/Users/test/anaconda/envs/test/lib/python2.7/site-packages/pyscipopt/__init__.py", line 3, in <module>
    from pyscipopt.scip      import Model
ImportError: dlopen(/Users/test/anaconda/envs/test/lib/python2.7/site-packages/pyscipopt/scip.so, 2): Symbol not found: _history_length
  Referenced from: /Users/test/Desktop/scipoptsuite-3.2.1/lib/libscipopt-3.2.1.darwin.x86_64.gnu.opt.so
  Expected in: flat namespace
 in /Users/test/Desktop/scipoptsuite-3.2.1/lib/libscipopt-3.2.1.darwin.x86_64.gnu.opt.so

Answer 1

When you set the SCIPOPTDIR environment variable, it looks for directories of the form ${SCIPOPTDIR}/scip-*/src.

You get that error because you do not have any directories that match that form in a freshly cloned checkout of PySCIPopt.git. You need to set that environment variable to the directory where you installed the "SCIP Optimization Suite".

Answer 2

You need to have SCIP installed first. The shared library of the SCIP Optimization Suite to be precise. The environment variable SCIPOPTDIR must then be set to its root directory - not the directory of the Python interface. Please follow the instructions in the INSTALL file carefully: https://github.com/SCIP-Interfaces/PySCIPOpt/blob/master/INSTALL.md