This error means ALAMO could not locate or run the simulator. To resolve it:

• Ensure the simulator exists and is accessible from your system's PATH, or
• Specify the full path to the simulator using ALAMO’s SIMULATOR option.

Note: ALAMO runs the simulator in a scratch directory, so the simulator should not rely on relative paths to locate other files or programs. Use absolute paths where needed.

Make sure you are using the latest version of ALAMO and generate a new license online. If the error persists, please send us a screenshot of ALAMO's output so we can help diagnose the issue.

• For Windows: Follow the instructions here.
• For Mac: Follow the instructions here.

After making the changes, restart your terminal and operating system to apply the updated path.

To license BARON:

• Go to minlp.com/baron-licenses to view licensing options, then email sales@minlp.com to purchase a license.
• You will receive a license file named baronlice.txt by email. Save it in one of the following locations:
  • In the same directory as the BARON executable, or
  • In your home directory (e.g., C:\Users\YourName\ on Windows or ~/ on Linux/macOS).
• Run BARON to confirm that your license is active. If not, a license error message will appear. For help, see the Error Messages and Support section below or contact info@minlp.com.

Free academic licenses are currently available only to individuals affiliated with Carnegie Mellon University, the University of Illinois at Urbana-Champaign, or the University System of Georgia.

However, all academic users receive discounted academic pricing on BARON licenses. These licenses are fully featured with no restrictions on problem size. 

For details, visit the BARON Licenses page.

All BARON licenses are perpetual. You only pay once, and your license is valid forever. You also get free access to all versions of BARON that are released within a year from your purchase.

Yes. When you purchase a BARON license, you receive free upgrades and technical support for the duration of your license. Renewal is strongly recommended to ensure ongoing access to the latest features and fixes.

Yes, BARON licenses are issued on a per-user basis, not per machine. This means you may install and use BARON on multiple machines—like a desktop, laptop, and across a computing cluster—as long as only the licensed user is using the software. If multiple people want to use BARON, you must have a multi-user license.

There are no restrictions on the number of instances you can run simultaneously. The user can run BARON on as many platforms, operating systems, and compute units as desired.

BARON supports the following operating systems:

• Windows
• Linux
• macOS (OS X)

You can download platform-specific executables from the BARON Downloads page.

Yes, BARON can be used completely offline. Once it is installed with a license on your machine, it does not require an internet connection to run.

BARON runs on 64-bit CPUs and is designed to be lightweight in hardware requirements. While exact resource needs depend on the problem, BARON can solve many models with just a few hundred megabytes of RAM. It uses dynamic memory allocation and will notify you if a problem exceeds your system's available resources.

This usually means there is a mismatch between your BARON version and the license file. Most likely, you are running an older version of BARON, but your new license is valid only for newer versions.

To resolve this:

• Remove the older BARON version from your system, or
• Update your system PATH to prioritize the latest BARON version that matches your license.

BARON shows this error when it cannot locate the required baronlice.txt license file. To resolve it:

1. Check your system PATH – Ensure the directory containing baronlice.txt is included in your PATH environment variable.
2. Use the LicName option – You can explicitly tell BARON where to find the license file:

On UNIX/Linux: LicName: "/home/username/baronlice.txt";

On Windows: LicName: "C:\Users\username\baronlice.txt";

Include this line in the OPTIONS section of your .bar file, or configure your modeling system (e.g., Pyomo, GAMS) to pass this option directly to BARON.

This error may occur due to formatting issues or version mismatches. Common causes include:

• Corruption from editing – Some Windows text editors (like Notepad) may introduce extra characters or line endings.
  ➤ Solution: Recopy the license file to the correct location without opening or modifying it in an editor.
• Version mismatch – You might be using a BARON version older than the license's effective date.
  ➤ Solution: Make sure you're using a BARON version released after the license date. Consider updating to the latest version.

This error may indicate that the license is not valid or the executable is corrupted. To troubleshoot:

• Run BARON from the command line to verify the installation:

  For example, on Windows, open the Command Prompt (cmd), then navigate to the folder where baron.exe is installed, and run: baron.exe path-to-your-input-file

If the error persists, consider reinstalling BARON or checking file permissions in the working directory.

If CompIIS appears to have no effect, check the results file—this is where BARON reports the Irreducible Infeasible Set (IIS), not the standard output.

Make sure:

• You are using a recent version of BARON that supports CompIIS.
• The results file is being properly generated and reviewed.

This issue usually occurs when BARON cannot locate the required CPLEX library files on your system. To resolve it:

1. Add the CPLEX library folder to your system’s dynamic library path, not just the PATH.
   • On Linux, update LD_LIBRARY_PATH.
   • On Windows, ensure the DLL folder is in your system environment variables.
2. Use the cplexlibname option to explicitly specify the library location. For example:
   • On Linux: cplexlibname: "/opt/ibm/ILOG/CPLEX_Studio221/cplex/bin/x86-64_linux/libcplex2211.so";
   • On Windows: cplexlibname: "C:\Program Files\ibmcplex\cplex2211.dll";
3. Allow time for changes to take effect, or restart your terminal/session if needed.

Include this option in your .bar file or pass it through your modeling interface.

Pyomo relies on the BARON executable being in your system PATH. If it is not found, follow these steps:

Check your PATH by running:

echo $PATH

This shows the directories Pyomo searches for executables.

• Add BARON to your PATH.
  If BARON is installed in, say, /usr/local/baron, add it like this:

  export PATH=/usr/local/baron:$PATH

• Make it permanent.
  Add the above line to your ~/.bashrc or ~/.bash_profile to preserve it across sessions.

After this, restart your terminal, and Pyomo should be able to locate BARON.

Please visit our MATLAB/BARON FAQ Page for solutions to common error messages and setup issues. If you need additional assistance, contact info@minlp.com for technical support.

Yes, ALAMO includes examples that demonstrate constrained regression, such as enforcing monotonicity or bounding model outputs. These examples are available in the example files provided on the ALAMO Downloads page. For using the constrained regression feature, please see Section 6.4 in the ALAMO user manual.

Adaptive sampling in ALAMO works by iteratively selecting new data points that maximize improvement in the model. It poses this as a black-box optimization problem using a surrogate model to identify high-uncertainty regions. The process continues until a stopping criterion is met, such as a target error or point limit.

The goal is to minimize costly data evaluations while building an accurate, interpretable model.

ALAMO requires at least one initial data point during the sampling stage. This point serves as the starting reference for building and refining the surrogate model. If no data is provided, ALAMO cannot evaluate model accuracy or guide sampling, and will terminate with an error.

ALAMO communicates with external simulators using text files. To use a simulator, you must provide a wrapper script that:

1. Reads input.txt – contains the points ALAMO wants to simulate.
2. Calls your simulator – runs simulations at those points.
3. Writes output.txt – returns the results for ALAMO to read.

Example Setup

Example wrappers are included in the examples folder:

• Windows: C:\alamo\examples
• Linux: /usr/local/alamo/examples

One useful example is in the batpython folder:

• In e1.alm, the line simulator e1.bat tells ALAMO to use e1.bat as the simulator wrapper.
• e1.bat runs: 
  python2.7 C:\alamo\e1.py 
  (Replace python2.7 with the version installed on your system.)

In e1.py:

• Line 28 performs the simulation (e.g., x^2).
• Other lines handle I/O — reading from input.txt and writing to output.txt.

Customizing for Your Simulator

To integrate your own simulator, replace line 28 of e1.py with code that:

• Launches your simulator
• Reads input(s) from input.txt
• Writes results to output.txt

Examples for Python, MATLAB, and executable-based simulators are included in the ALAMO software package.