ParameterVector
class qiskit.circuit.ParameterVector(name, length=0)
Bases: object
A container of many related Parameter objects.
This class is faster to construct than constructing many Parameter objects individually, and the individual names of the parameters will all share a common stem (the name of the vector). For a vector called v with length 3, the individual elements will have names v[0], v[1] and v[2].
The elements of a vector are sorted by the name of the vector, then the numeric value of their index.
This class fulfill the collections.abc.Sequence interface.
Attributes
name
The name of the ParameterVector.
params
A list of the contained ParameterVectorElement instances.
It is not safe to mutate this list.
Methods
index
index(value)
Find the index of a ParameterVectorElement within the list.
It is typically much faster to use the ParameterVectorElement.index property.
resize
resize(length)
Resize the parameter vector. If necessary, new elements are generated.
Note that the UUID of each Parameter element will be generated deterministically given the root UUID of the ParameterVector and the index of the element. In particular, if a ParameterVector is resized to be smaller and then later resized to be larger, the UUID of the later generated element at a given index will be the same as the UUID of the previous element at that index. This is to ensure that the parameter instances do not change.
>>> from qiskit.circuit import ParameterVector
>>> pv = ParameterVector("theta", 20)
>>> elt_19 = pv[19]
>>> rv.resize(10)
>>> rv.resize(20)
>>> pv[19] == elt_19
True