pythonPackages.scs: init at 2.1.1

Depends on libraries.science.math.scs.
Required by cvxpy -> qiskit-aer.

Co-authored-by: bhipple <bhipple@users.noreply.github.com>

pkgs/development/python-modules/scs/default.nix

@@ -0,0 +1,56 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, blas
+, liblapack
+, numpy
+, scipy
+, scs
+  # check inputs
+, nose
+}:
+
+buildPythonPackage rec {
+  inherit (scs) pname version;
+
+  src = fetchFromGitHub {
+    owner = "bodono";
+    repo = "scs-python";
+    rev = "f02abdc0e2e0a5851464e30f6766ccdbb19d73f0"; # need to choose commit manually, untagged
+    sha256 = "174b5s7cwgrn1m55jlrszdl403zhpzc4yl9acs6kjv9slmg1mmjr";
+  };
+
+  preConfigure = ''
+    rm -r scs
+    ln -s ${scs.src} scs
+  '';
+
+  buildInputs = [
+    liblapack
+    blas
+  ];
+
+  propagatedBuildInputs = [
+    numpy
+    scipy
+  ];
+
+  checkInputs = [ nose ];
+  checkPhase = ''
+    nosetests
+  '';
+  pythonImportsCheck = [ "scs" ];
+
+  meta = with lib; {
+    description = "Python interface for SCS: Splitting Conic Solver";
+    longDescription = ''
+      Solves convex cone programs via operator splitting.
+      Can solve: linear programs (LPs), second-order cone programs (SOCPs), semidefinite programs (SDPs),
+      exponential cone programs (ECPs), and power cone programs (PCPs), or problems with any combination of those cones.
+    '';
+    homepage = "https://github.com/cvxgrp/scs"; # upstream C package
+    downloadPage = "https://github.com/bodono/scs-python";
+    license = licenses.gpl3;
+    maintainers = with maintainers; [ drewrisinger ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -5080,6 +5080,8 @@ in {
   python-simple-hipchat = callPackage ../development/python-modules/python-simple-hipchat {};
   python_simple_hipchat = self.python-simple-hipchat;
 
+  scs = callPackage ../development/python-modules/scs { scs = pkgs.scs; };
+
   python_keyczar = callPackage ../development/python-modules/python_keyczar { };
 
   python-language-server = callPackage ../development/python-modules/python-language-server {};