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Installing MIMOSA

MIMOSA is written in Python, and can be installed using pip: 

pip install mimosa

If you don't have Python installed yet, we highly recommend to use Anaconda to install python.

Installing the optimisation engine IPOPT

Since MIMOSA is an optimisation model, an optimisation engine needs to be specified. We use the open-source optimisation engine IPOPT, which can be installed as a conda package.

conda install -c conda-forge ipopt=3.11.1

conda install -c idaes-pse -c conda-forge idaes-pse

conda install -c conda-forge ipopt

conda install -c conda-forge ipopt

Once IPOPT is installed, you can now solve your MIMOSA runs (see Running MIMOSA): 

from mimosa import MIMOSA, load_params

params = load_params()

model1 = MIMOSA(params)
model1.solve()
model1.save("run1")

Fixing the error IPOPT not found on Windows

Sometimes, installing IPOPT with conda fails on Windows. To fix it, go to https://github.com/coin-or/Ipopt/releases and download the latest win64-version. Unzip the files. A subfolder bin should contain the file ipopt.exe. The next step is to add this folder to your PATH environment: Windows > Edit the system environment variables > Environment variables... > Select "Path" and click Edit... > Click New and browse to the folder you just unzipped. Make sure to select the bin subfolder as this folder contains the file ipopt.exe.

  1. Once you've downloaded the zip file of the latest win64-version on the coin website (currently Ipopt-3.14.15-win64-msvs2019-md.zip), unzip this file to folder of your choice. In the unzipped folder, there should be a bin folder.
  2. The next step is to tell Windows to look for IPOPT in this bin directory. This is achieved by adding the relevant folder to the environment path of Windows. Click on Start (or press the Win key), type environment and press Enter. This should open the dialog Edit the system environment variables.
  3. Click on Environment variables, select Path and click edit.



  4. Here, you can add the folder with the IPOPT bin folder. Click on New and add the folder you unzipped IPOPT in, making sure to select the sub-folder bin:



  5. You can test if everything works by opening an Anaconda Prompt and typing ipopt. It should show something like this:



Running MIMOSA without local computations

If you don't want to install IPOPT on your computer, you can also use the NEOS server (https://neos-server.org) to run MIMOSA remotely. This way, the installation of IPOPT is not required. This can be useful if you don't want to use your own computer to do the runs. However, this is typically much slower than installing IPOPT locally.

First, on the NEOS website, sign up for a free account. You can then run MIMOSA with NEOS enabled by simply providing it with the email address you used to sign up for NEOS:

from mimosa import MIMOSA, load_params

params = load_params()

model1 = MIMOSA(params)
# Change "your.email@email.com" to your the email address you used to sign up for NEOS
model1.solve(use_neos=True, neos_email="your.email@email.com") 
model1.save("run1")

Depending on the MIMOSA parameters chosen and on how busy the NEOS server is, running the model might take a while (typically a couple of minutes).

Next: Running MIMOSA