Installation advice for noncommercial solvers added

docs/installation.rst

@@ -28,7 +28,7 @@ open source framework `Pyomo <http://www.pyomo.org/>`__ which supports several c
 
 Gurobi or Pyomo?
 -----------------
-You can work with ENTMOOT using Gurobi or Pyomo.
+You can work with ENTMOOT using the Gurobi interface or the modeling framework Pyomo.
 
 * `Gurobi <https://www.gurobi.com/>`__ is a commercial mathematical optimization solver which is very fast. Not only
   in solving the corresponding optimization problem but also in building it. Using Gurobi requires a valid license. Note
@@ -44,10 +44,28 @@ problems. The most common choices are the commercial solvers `Gurobi <https://ww
 `CBC <https://github.com/coin-or/Cbc/>`__  and `SCIP <https://www.scipopt.org
 />`__.
 
-Some help for Windows users with CBC and GLPK
------------------------------------------------------------------
+On the installation of noncommercial solvers
+=============================================
+Data scientists are used to install everything they need using
 
-If you are a Windows user and you want to use Pyomo with the free solvers CBC and/or GLPK, here is what you have to do.
+::
+
+   pip install everything_I_need
+
+Unfortunately, installing a free (i.e. noncommercial) solver is usually not that easy, so we provide some help in this
+section on how to install the solvers `GLPK <https://www.gnu.org/software/glpk/>`__,
+`CBC <https://github.com/coin-or/Cbc/>`__  and `SCIP <https://www.scipopt.org
+/>`__. We tested some types of installations (not all, though) for Windows and macOS and hope that this may help you.
+
+Which of the solvers CBC, GLPK and SCIP is best?
+---------------------------------------------
+SCIP is considered to be superior to GLPK and CBC in terms of speed and modeling features. However, CBC and GLPK are
+also widely used and there might be other reasons for you to use them, so we will guide you through the installation
+of all three solvers.
+
+Are you a Windows user who likes to download files?
+----------------------------------------------------
+If that is an option for you, you can follow these steps to install CBC and GLPK:
 
 1. Install the latest Microsoft Visual C++ Redistributable. You can get them
    `here <https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170>`_.
@@ -58,3 +76,51 @@ If you are a Windows user and you want to use Pyomo with the free solvers CBC an
 5. Insert these paths into the environment variable named ``PATH``. You can access this variable under System and
    Security>>System>>Advanced system settings>>Environment Variables. Then click on `path` in the top window, click the
    `Edit` button, then `New`.
+
+Are you a Windows user who likes to use conda?
+----------------------------------------------
+If you like to install your Python packages with conda, just use
+
+::
+
+   conda install -c conda-forge glpk
+
+to install GLPK and
+
+::
+
+    conda install -c conda-forge scip
+
+to install SCIP, respectively.
+
+Two remarks:
+
+1. It should also be possible to install CBC using conda but that did not work on my PC. Might be my fault, though.
+2. If you use Windows and Anaconda you might encounter an openSSL error, which occurs due to a bug from Anaconda.
+   `Here <https://community.anaconda.cloud/t/getting-openssl-working/51512/>`__ is some advice on how to fix it:
+
+Are you a macOS user?
+----------------------
+You may install *GLPK* with pip or conda using the commands
+
+::
+
+    pip install glpk
+
+or
+
+::
+
+   conda install -c conda-forge glpk
+
+The solvers *CBC* and *SCIP* can be installed via conda using
+
+::
+
+    conda install -c conda-forge coincbc
+
+or
+
+::
+
+    conda install -c conda-forge scip