qiskit.quantum_info.ScalarOp
class ScalarOp(dims, coeff=1)
Scalar identity operator class.
This is a symbolic representation of an scalar identity operator on multiple subsystems. It may be used to initialize a symbolic scalar multiplication of an identity and then be implicitly converted to other kinds of operator subclasses by using the compose(), dot(), tensor(), expand() methods.
Initialize an operator object.
Parameters
- dims (int or tuple) – subsystem dimensions.
- coeff (Number) – scalar coefficient for the identity operator (Default: 1).
Raises
QiskitError – If the optional coefficient is invalid.
__init__
__init__(dims, coeff=1)
Initialize an operator object.
Parameters
- dims (int or tuple) – subsystem dimensions.
- coeff (Number) – scalar coefficient for the identity operator (Default: 1).
Raises
QiskitError – If the optional coefficient is invalid.
Methods
__init__(dims[, coeff]) | Initialize an operator object. |
add(other) | Return the linear operator self + other. |
adjoint() | Return the adjoint of the operator. |
compose(other[, qargs, front]) | Return the composed operator. |
conjugate() | Return the conjugate of the operator. |
copy() | Make a deep copy of current operator. |
dot(other[, qargs]) | Return the right multiplied operator self * other. |
expand(other) | Return the tensor product operator other ⊗ self. |
input_dims([qargs]) | Return tuple of input dimension for specified subsystems. |
is_unitary([atol, rtol]) | Return True if operator is a unitary matrix. |
multiply(other) | Return the linear operator other * self. |
output_dims([qargs]) | Return tuple of output dimension for specified subsystems. |
power(n) | Return the power of the ScalarOp. |
reshape([input_dims, output_dims]) | Return a shallow copy with reshaped input and output subsystem dimensions. |
set_atol(value) | Set the class default absolute tolerance parameter for float comparisons. |
set_rtol(value) | Set the class default relative tolerance parameter for float comparisons. |
subtract(other) | Return the linear operator self - other. |
tensor(other) | Return the tensor product operator self ⊗ other. |
to_matrix() | Convert to a Numpy matrix. |
to_operator() | Convert to an Operator object. |
transpose() | Return the transpose of the operator. |
Attributes
atol | The default absolute tolerance parameter for float comparisons. |
coeff | Return the coefficient |
dim | Return tuple (input_shape, output_shape). |
num_qubits | Return the number of qubits if a N-qubit operator or None otherwise. |
qargs | Return the qargs for the operator. |
rtol | The relative tolerance parameter for float comparisons. |
add
add(other)
Return the linear operator self + other.
DEPRECATED: use operator + other instead.
Parameters
other (BaseOperator) – an operator object.
Returns
the operator self + other.
Return type
BaseOperator
adjoint
adjoint()
Return the adjoint of the operator.
atol
The default absolute tolerance parameter for float comparisons.
coeff
Return the coefficient
compose
compose(other, qargs=None, front=False)
Return the composed operator.
Parameters
- 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].
Returns
The operator self @ other.
Return type
BaseOperator
Raises
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.
conjugate
conjugate()
Return the conjugate of the operator.
copy
copy()
Make a deep copy of current operator.
dim
Return tuple (input_shape, output_shape).
dot
dot(other, qargs=None)
Return the right multiplied operator self * other.
Parameters
- 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].
Returns
The operator self * other.
Return type
BaseOperator
Raises
QiskitError – if other cannot be converted to an operator, or has incompatible dimensions for specified subsystems.
expand
expand(other)
Return the tensor product operator other ⊗ self.
Parameters
other (BaseOperator) – an operator object.
Returns
if other is an ScalarOp. BaseOperator: if other is not an ScalarOp.
Return type
input_dims
input_dims(qargs=None)
Return tuple of input dimension for specified subsystems.
is_unitary
is_unitary(atol=None, rtol=None)
Return True if operator is a unitary matrix.
multiply
multiply(other)
Return the linear operator other * self.
DEPRECATED: use other * operator instead.
Parameters
other (complex) – a complex number.
Returns
the linear operator other * self.
Return type
BaseOperator
Raises
NotImplementedError – if subclass does not support multiplication.
num_qubits
Return the number of qubits if a N-qubit operator or None otherwise.
output_dims
output_dims(qargs=None)
Return tuple of output dimension for specified subsystems.
power
power(n)
Return the power of the ScalarOp.
Parameters
n (Number) – the exponent for the scalar op.
Returns
the coeff ** n ScalarOp.
Return type
Raises
QiskitError – if the input and output dimensions of the operator are not equal, or the power is not a positive integer.
qargs
Return the qargs for the operator.
reshape
reshape(input_dims=None, output_dims=None)
Return a shallow copy with reshaped input and output subsystem dimensions.
Arg:
input_dims (None or tuple): new subsystem input dimensions.
If None the original input dims will be preserved [Default: None].
output_dims (None or tuple): new subsystem output dimensions.
If None the original output dims will be preserved [Default: None].
Returns
returns self with reshaped input and output dimensions.
Return type
BaseOperator
Raises
QiskitError – if combined size of all subsystem input dimension or subsystem output dimensions is not constant.
rtol
The relative tolerance parameter for float comparisons.
set_atol
classmethod set_atol(value)
Set the class default absolute tolerance parameter for float comparisons.
DEPRECATED: use operator.atol = value instead
set_rtol
classmethod set_rtol(value)
Set the class default relative tolerance parameter for float comparisons.
DEPRECATED: use operator.rtol = value instead
subtract
subtract(other)
Return the linear operator self - other.
DEPRECATED: use operator - other instead.
Parameters
other (BaseOperator) – an operator object.
Returns
the operator self - other.
Return type
BaseOperator
tensor
tensor(other)
Return the tensor product operator self ⊗ other.
Parameters
other (BaseOperator) – an operator object.
Returns
if other is an ScalarOp. BaseOperator: if other is not an ScalarOp.
Return type
to_matrix
to_matrix()
Convert to a Numpy matrix.
to_operator
to_operator()
Convert to an Operator object.
transpose
transpose()
Return the transpose of the operator.