4.1.1.3.1.2. pyfem.fem.Constrainer module

class Constrainer(nDofs: int, name: str = 'Main')

Bases: object

Container for handling multi-point constraints (ties/prescribed dofs).

The class records constraint relations and can build a sparse constraint matrix as a scipy.sparse.coo_matrix. It also manages groups of constrained DOFs, their prescribed values and scaling factors per load-case or name.

addConstraint(dofID: int, val: Any, label: str) → None

Register a constraint on a DOF.

The val argument may be a scalar or a triplet [value, masterID, factor] representing a tied DOF. The method updates internal structures that are later used to build the constraint matrix.

checkConstraints(dofspace: Any, nodeTables: Any) → None

Resolve chained tying relations and expand slave prescriptions.

This method processes entries in self.constrainData that indicate tied DOFs using the [value, master, factor] convention and flattens recursive ties so that slaves with masters that are themselves slaves are resolved to base values.

flush() → None

Build and store the sparse constraint matrix self.C.

The returned matrix maps the full DOF vector to the reduced set of free DOFs. Slave entries are added to the matrix based on previously recorded master/slave relations.

addConstrainedValues(a: Any) → None

Add the constrained values into array a (incremental).

The method loops over named constraint groups and increments the entries in a by scaled prescribed values.

setConstrainedValues(a: Any) → None

Overwrite entries in a with constrained values.

setConstrainFactor(fac: float, loadCase: str = 'All_') → None

Set the constraint scaling factor for all or a specific load case.

setPrescribedDofs(a: Any, val: float = 0.0) → None

Set prescribed DOFs in array a to a scalar value.

setFactorForDof(fac: float, dofID: int, label: str) → None

Add a factor to the prescribed value for a specific DOF.

slaveCount() → int

Return the total number of constrained (slave) DOFs.