License Management

This page describes how to manage your QUBO++ license using the qbpp-license command-line utility. The license system is shared between QUBO++ (C++) and PyQUBO++ (Python).

License Types

QUBO++ offers several license types with different variable count limits and validity periods.

• Anonymous Trial: No registration required. Automatically activated on first use.
• Registered Trial: Requires a free license key for evaluation purposes.
• Standard License: For production use. Supports large-scale CPU optimization.
• Professional License: For production use with GPU acceleration (ABS3 Solver, Exhaustive Solver).
• Fallback Mode: When no valid license is found or the license has expired, QUBO++ runs with a 100-variable limit.

Setting the License Key

If you have a license key, set it using one of the following methods.

Method 1: Environment Variable (recommended)

Add the following line to your ~/.bashrc:

export QBPP_LICENSE_KEY=XXXXXX-XXXXXX-XXXXXX-XXXXXX

Then reload the shell:

$ source ~/.bashrc

Method 2: Command-Line Option

Pass the key directly to qbpp-license:

$ qbpp-license -k XXXXXX-XXXXXX-XXXXXX-XXXXXX -a

Method 3: In C++ Code

Set the key programmatically before creating variables:

#include <qbpp/qbpp.hpp>

int main() {
    qbpp::license_key("XXXXXX-XXXXXX-XXXXXX-XXXXXX");
    // ... your QUBO++ code ...
}

Note: For Anonymous Trial, no license key is needed. Simply run qbpp-license -a without setting a key.

Activating a License

A license must be activated on each machine before QUBO++ programs can use it. Activation is node-locked – the license is tied to the specific machine.

$ qbpp-license -a

• This contacts the license server and registers the current machine.
• Each activation consumes one slot from the license’s activation limit.
• If the license is already activated on this machine, running -a again does not consume an additional slot.

Checking License Status

To display the current license status without making any changes:

$ qbpp-license

This shows the license type, expiry date, variable limits, and activation usage. The command contacts the license server to refresh the status.

Deactivating a License

To move a license to another machine, first deactivate it on the current machine:

$ qbpp-license -d

• Deactivation frees up one activation slot.
• Anonymous Trial licenses cannot be deactivated.
• There is a 24-hour cooldown between consecutive deactivations to prevent abuse.

Warning: Each license key has a limited number of allowed activations and deactivations. Once the total reaches this limit, you will no longer be able to activate or deactivate that license. Plan your activations carefully.

Command Reference

Usage: qbpp-license [options]

Options:
  -h, --help         Show help message and exit
  -k, --key KEY      Specify a license key
  -a, --activate     Activate the license on this machine
  -d, --deactivate   Deactivate the license on this machine
  -t, --time-out SEC Set the server communication timeout (default: 20 seconds)

Examples

How License Verification Works

• qbpp-license command: Always contacts the license server to get the latest status. This may take a few seconds depending on network conditions.
• QUBO++ programs: Verify the license using the local cache (~/.qbpp/license_cache) and do not block on server communication. The server is contacted only when the cache needs to be refreshed (e.g., after a long period without synchronization).
• Offline use: Once activated, the license works offline using the cached credentials. No persistent internet connection is required for running QUBO++ programs.

Network and Timeout

If your network is slow or behind a firewall/proxy, the default 20-second timeout may not be enough.

To increase the timeout:

$ qbpp-license -t 60 -a

If the server is unreachable, QUBO++ falls back to the cached license status. If no cache exists, QUBO++ runs in Fallback Mode (100-variable limit).

Troubleshooting

“License server timed out”

• Check your internet connection.
• Increase the timeout: qbpp-license -t 60
• If you are behind a corporate firewall or proxy, ensure outbound HTTPS traffic is allowed.

“Activation limit reached”

• Each license has a limited number of activation/deactivation slots.
• Deactivate on machines you no longer use: qbpp-license -d
• Contact the license administrator to increase the activation limit if needed.

“License expired”

• Trial licenses have a fixed validity period (7 days for Anonymous, 30 days for Registered).
• Contact the distributor to renew or upgrade your license.
• QUBO++ continues to work in Fallback Mode (100-variable limit) after expiry.

Programs work but with limited variables

• QUBO++ may be running in Fallback Mode. Check the license status:

  $ qbpp-license
  

• Ensure the license key is set correctly via QBPP_LICENSE_KEY or qbpp::license_key().
• Re-activate if necessary: qbpp-license -a

“Deactivation cooldown”

• There is a 24-hour waiting period between consecutive deactivations.
• Wait and try again after the cooldown period has elapsed.

Floating Licenses

Floating licenses allow shared access across multiple machines within an organization. Instead of being permanently locked to a machine, a floating license uses a lease-based mechanism.

• A floating license key is prefixed with F- (e.g., F-XXXXXX-XXXXXX-XXXXXX-XXXXXX).
• When a QUBO++ program starts, it acquires a lease from the license server.
• The lease is automatically renewed while the program is running.
• When the program exits, the lease is released, making the slot available for other machines.
• If the program crashes or the network is lost, the lease expires automatically after a timeout period.

Usage is the same as node-locked licenses:

$ export QBPP_LICENSE_KEY=F-XXXXXX-XXXXXX-XXXXXX-XXXXXX
$ qbpp-license -a