ScalarOp.compose(other, qargs=None, front=False)[source]

Return the composed operator.

  • other (BaseOperator) – an operator object.

  • qargs (list or None) – a list of subsystem positions to apply other on. If None apply on all subsystems [default: None].

  • front (bool) – If True compose using right operator multiplication, instead of left multiplication [default: False].


The operator self @ other.

Return type



QiskitError – if other has incompatible dimensions for specified subsystems.

Additional Information:

Composition (@) is defined as left matrix multiplication for matrix operators. That is that A @ B is equal to B * A. Setting front=True returns right matrix multiplication A * B and is equivalent to the dot() method.