Running gulls

After configuring your environment and meeting all prerequisites, follow these steps to run simulations with the GULLS Simulator.

Building the Simulator

Open the Makefile: Navigate to the GULLS source directory and open the Makefile:
```
cd /path/to/gulls/src/
open Makefile
```
Configure the Makefile: Edit the Makefile to set the BASEDIR and compiler flags such as FFLAGS, CFLAGS, and LINKERFLAGS to match your system's configuration.
Select an Executable: Based on your simulation needs, choose an executable from the list defined in the Makefile. For instance, to simulate single lens microlensing events, you would focus on gullsSingle.
Build the Executable: Compile the chosen executable by running:
```
make gullsSingle
```
Clean up any intermediate files if necessary:
```
make clean
```

Running a Simulation

Change to the Bin Directory: Once the build process completes, navigate to the bin directory:
```
cd /path/to/gulls/bin
```
Execute the Simulator: Launch the GULLS simulator by running the built executable. For example:
```
./gullsSingle.x
```
You'll be prompted with usage guidelines. Follow these to run your simulation effectively.
Simulation Input: Prepare your input parameter file (e.g., singlelens.prm) and specify it when running the simulator. Adjust the flags according to your needs:
- -i: Path to the input parameter file.
- -s: Simulation instance number, usually set to 0 for initial runs.
- -f: Field number for the observation, if applicable.
- -d: Debug mode, can be repeated for increased verbosity.
Example command:
```
./gullsSingle.x -i PATH/singlelens.prm -s 0 -f 83 -d
```
This command initiates the simulation with specified parameters and outputs data to the OUTPUT_DIR configured in your parameter file.

Congratulations! You've successfully run a simulation with the GULLS Simulator. Explore the output in your specified directory, and adjust parameters for further simulations as needed.