# SIMPLE-G Model Execution Guide using GEMPACK

This README provides instructions on how to run a SIMPLE-G model using the GEMPACK software.

## Prerequisites
- Ensure you have GEMPACK installed on your system.
- Have the model files ready from ZIP archive, typically with a `.CMF`, `.TAB`, `.EXE` extension.

## Steps to Run the Model

### Step 1: Open the Command File
- Navigate to the directory containing your model files.
- Locate the Command (`*.CMF`) files associated with your model. Seven .cmf files are placed to replicate the results in Liu et al. (2023). Detailed descriptions, corresponding to Table 1 in the chapter and the paper are as follows. 
- E1 (N loss tax); E2 (Split N); E3 (Controlled drainage); E4 (Wetlands); E5 (Tax + Split N); E6 (Tax + Split N + Controlled drainage); E7 (Tax + Split N + (Wetlands).

### Step 2: Load the Command File
- Open the `CMF` file using TABmate utility.

### Step 3: Run the Model
- Once the Command file is loaded, you can run the model by clicking on the `Run CMF` button.
- Look at top icons.
- Go to `RUN CMF` > `Browse Tab file` and select the `.TAB` file to load your model.
- Uncheck `Run With GEMSIM`.
- Click `OK` to run.
- Monitor the process through the output window for any errors or messages.

## Post-Execution
- After the model has finished running, check the `out` directory for results.
- Analyze the output files using the appropriate tools within GEMPACK.

## Troubleshooting
- If you encounter any issues, refer to the GEMPACK documentation or contact support for assistance.


Thank you for using GEMPACK for your SIMPLE-G modeling needs.

# Reference: Liu, J., Bowling, L., Kucharik, C., Jame, S., Baldos, U., Jarvis, L., Ramankutty, N. and Hertel, T., 2023. Tackling policy leakage and targeting hotspots could be key to addressing the ‘Wicked’challenge of nutrient pollution from corn production in the US. Environmental Research Letters, 18(10), p.105002.
# author: Jing Liu
# contact: liu207@purdue.edu
# website: https://www.gtap.agecon.purdue.edu/access_staff/network/member_display.asp?UserID=11198 