add COPT solver

[fneum]

closes #186

https://shanshu.ai/copt

Documentation: https://guide.coap.online/copt/en-doc/index.html

Install with pip install coptpy

Commercial, free academic license.

Tested locally and passed all tests. However, quadratic problems are not supported yet (LP file format issues?).

Small problem instances do not require a license. Hence, this solver can be tested in CI.

COPT could also calculate IIS (for later).

import pypsa

n = pypsa.examples.ac_dc_meshed()
n.optimize(solver_name='highs')
n.buses_t.marginal_price["London"]
n.generators_t.p
n.optimize(solver_name='copt', solver_options=dict(LpMethod=2))
n.generators_t.p
n.buses_t.marginal_price["London"]

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (c1186a3) 89.22% compared to head (0557525) 89.25%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #190      +/-   ##
==========================================
+ Coverage   89.22%   89.25%   +0.03%     
==========================================
  Files          15       15              
  Lines        3136     3182      +46     
  Branches      723      731       +8     
==========================================
+ Hits         2798     2840      +42     
- Misses        234      237       +3     
- Partials      104      105       +1     

Files	Coverage Δ
linopy/solvers.py	90.10% <91.30%> (+0.16%)	⬆️

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[FabianHofmann]

Wow, super nice! I hope I can review soon, but it looks very good on the first glimpse (same for #189, #188 )

[loongmxbt]

Hi, copt also support quadratic problem, hope to add to quadratic solvers option.

ValueError: Solver copt does not support quadratic problems