SparseVectorStateFn
class SparseVectorStateFn(primitive, coeff=1.0, is_measurement=False)
Bases: qiskit.opflow.state_fns.state_fn.StateFn
A class for sparse state functions and measurements in vector representation.
This class uses scipy.sparse.spmatrix for the internal representation.
Parameters
- primitive (
spmatrix) – The underlying sparse vector. - coeff (
Union[complex,ParameterExpression]) – A coefficient multiplying the state function. - is_measurement (
bool) – Whether the StateFn is a measurement operator
Raises
- ValueError – If the primitive is not a column vector.
- ValueError – If the number of elements in the primitive is not a power of 2.
Methods Defined Here
add
SparseVectorStateFn.add(other)
Return Operator addition of self and other, overloaded by +.
Parameters
other (OperatorBase) – An OperatorBase with the same number of qubits as self, and in the same ‘Operator’, ‘State function’, or ‘Measurement’ category as self (i.e. the same type of underlying function).
Return type
Returns
An OperatorBase equivalent to the sum of self and other.
adjoint
SparseVectorStateFn.adjoint()
Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by ~. For StateFns, this also turns the StateFn into a measurement.
Return type
Returns
An OperatorBase equivalent to the adjoint of self.
equals
SparseVectorStateFn.equals(other)
Evaluate Equality between Operators, overloaded by ==. Only returns True if self and other are of the same representation (e.g. a DictStateFn and CircuitStateFn will never be equal, even if their vector representations are equal), their underlying primitives are equal (this means for ListOps, OperatorStateFns, or EvolvedOps the equality is evaluated recursively downwards), and their coefficients are equal.
Parameters
other (OperatorBase) – The OperatorBase to compare to self.
Return type
bool
Returns
A bool equal to the equality of self and other.
eval
SparseVectorStateFn.eval(front=None)
Evaluate the Operator’s underlying function, either on a binary string or another Operator. A square binary Operator can be defined as a function taking a binary function to another binary function. This method returns the value of that function for a given StateFn or binary string. For example, op.eval('0110').eval('1110') can be seen as querying the Operator’s matrix representation by row 6 and column 14, and will return the complex value at those “indices.” Similarly for a StateFn, op.eval('1011') will return the complex value at row 11 of the vector representation of the StateFn, as all StateFns are defined to be evaluated from Zero implicitly (i.e. it is as if .eval('0000') is already called implicitly to always “indexing” from column 0).
If front is None, the matrix-representation of the operator is returned.
Parameters
front (Union[str, Dict[str, complex], ndarray, OperatorBase, Statevector, None]) – The bitstring, dict of bitstrings (with values being coefficients), or StateFn to evaluated by the Operator’s underlying function, or None.
Return type
Union[OperatorBase, complex]
Returns
The output of the Operator’s evaluation function. If self is a StateFn, the result is a float or complex. If self is an Operator (PrimitiveOp, ComposedOp, SummedOp, EvolvedOp, etc.), the result is a StateFn. If front is None, the matrix-representation of the operator is returned, which is a MatrixOp for the operators and a VectorStateFn for state-functions. If either self or front contain proper ListOps (not ListOp subclasses), the result is an n-dimensional list of complex or StateFn results, resulting from the recursive evaluation by each OperatorBase in the ListOps.
primitive_strings
SparseVectorStateFn.primitive_strings()
Return a set of strings describing the primitives contained in the Operator. For example, {'QuantumCircuit', 'Pauli'}. For hierarchical Operators, such as ListOps, this can help illuminate the primitives represented in the various recursive levels, and therefore which conversions can be applied.
Return type
Set[str]
Returns
A set of strings describing the primitives contained within the Operator.
sample
SparseVectorStateFn.sample(shots=1024, massive=False, reverse_endianness=False)
Sample the state function as a normalized probability distribution. Returns dict of bitstrings in order of probability, with values being probability.
Parameters
- shots (
int) – The number of samples to take to approximate the State function. - massive (
bool) – Whether to allow large conversions, e.g. creating a matrix representing over 16 qubits. - reverse_endianness (
bool) – Whether to reverse the endianness of the bitstrings in the return dict to match Terra’s big-endianness.
Return type
dict
Returns
A dict containing pairs sampled strings from the State function and sampling frequency divided by shots.
to_circuit_op
SparseVectorStateFn.to_circuit_op()
Convert this state function to a CircuitStateFn.
Return type
to_dict_fn
SparseVectorStateFn.to_dict_fn()
Convert this state function to a DictStateFn.
Return type
Returns
A new DictStateFn equivalent to self.
to_matrix
SparseVectorStateFn.to_matrix(massive=False)
Return NumPy representation of the Operator. Represents the evaluation of the Operator’s underlying function on every combination of basis binary strings. Warn if more than 16 qubits to force having to set massive=True if such a large vector is desired.
Return type
ndarray
Returns
The NumPy ndarray equivalent to this Operator.
to_matrix_op
SparseVectorStateFn.to_matrix_op(massive=False)
Return a VectorStateFn for this StateFn.
Parameters
massive (bool) – Whether to allow large conversions, e.g. creating a matrix representing over 16 qubits.
Return type
Returns
A VectorStateFn equivalent to self.
to_spmatrix
SparseVectorStateFn.to_spmatrix()
Return SciPy sparse matrix representation of the Operator. Represents the evaluation of the Operator’s underlying function on every combination of basis binary strings.
Return type
Returns
The SciPy spmatrix equivalent to this Operator.
Attributes
INDENTATION
Default value: ' '
coeff
A coefficient by which the state function is multiplied.
Return type
Union[complex, ParameterExpression]
instance_id
Return the unique instance id.
Return type
int
is_measurement
Whether the StateFn object is a measurement Operator.
Return type
bool
num_qubits
Return type
int
parameters
primitive
Type: scipy.sparse._base.spmatrix
The primitive which defines the behavior of the underlying State function.
settings
Return settings.
Return type
Dict