License management#

Overview#

PyMechanical provides comprehensive license management capabilities through the LicenseManager class for embedded Mechanical applications. This feature enables fine-grained control over Ansys Mechanical licenses, including the ability to:

  • Start applications without checking out a license (read-only mode)

  • Choose specific licenses to check out

  • Change the order of license preferences

  • Enable or disable specific licenses

  • Manage licenses dynamically during a session

Note

License management features are available starting from Ansys Mechanical 2025 R2 (version 252) and later.

What’s new#

Recent enhancements to PyMechanical include:

  • License Selection at Startup: New start_license parameter in the App constructor allows you to specify which license to check out when starting the application.

  • Read-Only Mode: New readonly parameter enables starting Mechanical without checking out a license.

  • License Manager API: New LicenseManager class provides programmatic control over license preferences and session licenses.

These features provide greater flexibility for workflows that require specific licensing configurations or need to minimize license usage.

License keywords and products#

When using the start_license parameter, you can specify licenses using license keywords. The following table shows the available license keywords and their corresponding Ansys products:

Solver licenses#

These licenses provide full solve capabilities:

Solver License Keywords#

Keyword

Product

ansys

Ansys Mechanical Enterprise

mech_1

Ansys Mechanical Pro

mech_2

Ansys Mechanical Premium

meba

Ansys Mechanical Enterprise Solver

dyna

Ansys LS-DYNA

PrepPost (non-solver) licenses#

These licenses provide pre-processing and post-processing capabilities without solver access:

PrepPost License Keywords#

Keyword

Product

preppost

Ansys Mechanical Enterprise PrepPost

dynapp

Ansys LS-DYNA PrepPost

acdi_adprepost

Ansys AUTODYN PrepPost

Note

When specifying a license keyword with start_license, use only the keyword (for example, start_license="meba"). The license names returned by get_all_licenses() use the full product names (for example, “Ansys Mechanical Premium”).

Starting the application#

Without a license (read-only mode)#

You can start Mechanical in read-only mode without checking out a license. This is useful for viewing results or exploring projects without consuming a license:

from ansys.mechanical.core import App

# Start in read-only mode
app = App(readonly=True, version=252)

# Verify read-only status
print(f"Read-only mode: {app.readonly}")  # Output: True

Note

In read-only mode, you cannot modify the model or perform operations that require write access.

With a specific license#

You can specify which license to check out when starting the application using the start_license parameter:

from ansys.mechanical.core import App

# Start with Mechanical Enterprise Solver license
app = App(start_license="meba", version=252)

# Start with Mechanical Premium license
app = App(start_license="mech_2", version=252)

# Start with Mechanical Pro license
app = App(start_license="mech_1", version=252)

# Start with Mechanical Enterprise license
app = App(start_license="ansys", version=252)

Tip

Refer to the License Keywords and Products section above for a complete list of available license keywords.

Warning

The start_license parameter is ignored when readonly=True.

With default license#

By default, when neither readonly nor start_license is specified, Mechanical checks out the first enabled license in the preference order:

from ansys.mechanical.core import App

# Start with default license behavior
app = App(version=252)

# Check which license was checked out
print(app.license_manager.get_all_licenses())

License manager API#

The LicenseManager class provides comprehensive license management capabilities. Access it through the license_manager property of the App instance:

from ansys.mechanical.core import App

app = App(version=252)
license_mgr = app.license_manager

Viewing available licenses#

Get a list of all available licenses:

# Get all licenses in preference order
licenses = license_mgr.get_all_licenses()
print(licenses)
# Output: ['Ansys Mechanical Enterprise', 'Ansys Mechanical Premium', 'Ansys Mechanical Pro']

Display license status information:

# Show all licenses with their status
license_mgr.show()
# Output:
# Ansys Mechanical Enterprise - Enabled
# Ansys Mechanical Premium - Enabled
# Ansys Mechanical Pro - Disabled

Checking license status#

Check if a specific license is enabled or disabled:

# Get status of a specific license
status = license_mgr.get_license_status("Ansys Mechanical Premium")
print(status)  # Output: LicenseStatus.Enabled or LicenseStatus.Disabled

Enabling and disabling licenses#

Enable or disable specific licenses in your preference list:

# Disable a license so it won't be checked out
license_mgr.set_license_status("Ansys Mechanical Pro", False)

# Enable a license
license_mgr.set_license_status("Ansys Mechanical Premium", True)

Note

Changes made with set_license_status are persisted to user preferences and affect future sessions.

Changing license order#

Change the priority order of licenses. Mechanical attempts to check out licenses in order from index 0 (highest priority):

# Move Ansys Mechanical Premium to first priority (index 0)
license_mgr.move_to_index("Ansys Mechanical Premium", 0)

# Verify the new order
licenses = license_mgr.get_all_licenses()
print(licenses)
# Output: ['Ansys Mechanical Premium', 'Ansys Mechanical Enterprise', 'Ansys Mechanical Pro']

Note

License order changes are saved to user preferences.

Resetting license preferences#

Reset all license preferences (order and status) to default values:

# Reset to default license preferences
license_mgr.reset_preference()

# Verify preferences were reset
licenses = license_mgr.get_all_licenses()
print(licenses)

Session license management#

Session licenses are temporary license checkouts that only affect the current Mechanical session. Unlike preference changes, session license changes are not persisted.

Disabling session license#

Disable the currently checked-out license to put the application in read-only mode:

from ansys.mechanical.core import App

app = App(version=252)

# Initially not in read-only mode
print(app.readonly)  # Output: False

# Disable the session license
app.license_manager.disable_session_license()

# Now in read-only mode
print(app.readonly)  # Output: True

Enabling session license#

Enable a license for the current session. This is useful for temporarily checking out a license when the application is in read-only mode:

# Enable default license (first enabled in preference order)
app.license_manager.enable_session_license()

print(app.readonly)  # Output: False

Enable a specific license:

# Enable a specific license
app.license_manager.enable_session_license("Ansys Mechanical Premium")

print(app.readonly)  # Output: False

Enable multiple licenses with priority order:

# Try to check out licenses in the specified order
app.license_manager.enable_session_license([
    "Ansys Mechanical Enterprise",
    "Ansys Mechanical Premium"
])

print(app.readonly)  # Output: False

Advanced workflows#

Choosing a specific license (workaround)#

If you need to ensure a specific license is checked out when multiple licenses are available, you can use the read-only workaround:

from ansys.mechanical.core import App

# Method 1: Using start_license parameter (recommended)
app = App(start_license="meba", version=252)  # Forces Mechanical Premium

# Method 2: Using read-only workaround
app = App(readonly=True, version=252)  # Start without license

# Modify license order
app.license_manager.move_to_index("Ansys Mechanical Premium", 0)

# Enable the desired license
app.license_manager.enable_session_license("Ansys Mechanical Premium")

# Now using the specific license
print(app.readonly)  # Output: False

Changing license mid-session#

You can change which license is checked out during a session:

from ansys.mechanical.core import App

app = App(version=252)

# Check current license status
print("Currently using:")
app.license_manager.show()

# Switch to read-only (releases current license)
app.license_manager.disable_session_license()
print(f"\nRead-only mode: {app.readonly}")

# Change license preference order
app.license_manager.move_to_index("Ansys Mechanical Pro", 0)

# Check out the new preferred license
app.license_manager.enable_session_license()

print("\nAfter license change:")
app.license_manager.show()
print(f"Read-only mode: {app.readonly}")

Minimizing license usage#

For workflows that involve long periods of data processing or waiting, you can temporarily release the license:

from ansys.mechanical.core import App
import time

app = App(version=252)

# Perform operations requiring a license
# ... your modeling operations ...

# Release license during long computation
app.license_manager.disable_session_license()

# Perform operations that don't require write access
# ... data processing, waiting for user input, etc. ...
time.sleep(300)  # 5 minutes of processing

# Re-acquire license for further modeling
app.license_manager.enable_session_license()

# Continue with modeling operations
# ... more operations ...

Testing license availability#

Test if specific licenses are available before starting:

from ansys.mechanical.core import App

app = App(readonly=True, version=252)  # Start without checking out a license

# Check which licenses are available
licenses = app.license_manager.get_all_licenses()
print("Available licenses:", licenses)

# Try to enable a preferred license
preferred_licenses = [
    "Ansys Mechanical Enterprise",
    "Ansys Mechanical Premium",
    "Ansys Mechanical Pro"
]

for lic in preferred_licenses:
    if lic in licenses:
        status = app.license_manager.get_license_status(lic)
        print(f"{lic}: {status}")

# Enable with fallback priority
app.license_manager.enable_session_license(preferred_licenses)
print(f"Read-only mode: {app.readonly}")

Troubleshooting#

License not available#

If you try to enable a license that is not available:

app.license_manager.enable_session_license("Ansys Mechanical Premium")

# If license is not available, app will remain in read-only mode
if app.readonly:
    print("Warning: Requested license not available. Application is in read-only mode.")
    # Try alternative license
    app.license_manager.enable_session_license("Ansys Mechanical Pro")

Checking read-only status#

Always verify the read-only status before performing write operations:

if app.readonly:
    print("Application is in read-only mode. No write operations possible.")
else:
    print("Application has an active license. Write operations allowed.")

Version compatibility#

License management features require Mechanical 2025 R2 or later:

from ansys.mechanical.core import App

app = App(version=242)  # Older version

try:
    license_mgr = app.license_manager
except Exception as e:
    print(e)
    # Output: "LicenseManager is only available for version 252 and later."

Best practices#

  1. Use start_license for predictable startup: When you know which license you need, use the start_license parameter instead of manipulating preferences.

  2. Release Licenses When Idle: Use disable_session_license() during long idle periods to free up licenses for other users.

  3. Test License Availability: In multi-user environments, start in read-only mode and check license availability before attempting to check out a license.

  4. Preserve User Preferences: Be aware that set_license_status() and move_to_index() modify user preferences permanently. Use reset_preference() to restore defaults if needed.

  5. Handle license failures gracefully: Always check app.readonly status before attempting write operations to handle license unavailability.

Example: Complete license management workflow#

Here’s a complete example demonstrating various license management scenarios:

from ansys.mechanical.core import App

# Start in read-only mode to inspect license options
app = App(readonly=True, version=252)

print("=== Available Licenses ===")
app.license_manager.show()

print("\n=== Configure License Preferences ===")
# Set preferred license order
app.license_manager.move_to_index("Ansys Mechanical Premium", 0)
app.license_manager.move_to_index("Ansys Mechanical Enterprise", 1)

# Disable a license we don't want to use
app.license_manager.set_license_status("Ansys Mechanical Pro", False)

print("\nUpdated license order:")
licenses = app.license_manager.get_all_licenses()
for idx, lic in enumerate(licenses):
    status = app.license_manager.get_license_status(lic)
    print(f"  {idx}: {lic} - {status}")

print("\n=== Check Out License ===")
# Enable the preferred license
app.license_manager.enable_session_license()

if not app.readonly:
    print("License checked out successfully")
    # Perform modeling operations
    print("Performing modeling operations...")
    # ... your code here ...
else:
    print("Failed to check out license")

print("\n=== Release License Temporarily ===")
app.license_manager.disable_session_license()
print(f"Read-only mode: {app.readonly}")

# Perform operations that don't need a license
print("Performing read-only operations...")

print("\n=== Re-acquire License ===")
app.license_manager.enable_session_license()
print(f"Read-only mode: {app.readonly}")

print("\n=== Reset to Defaults ===")
app.license_manager.reset_preference()
print("License preferences reset to default")

Additional resources#