ReadoutError
class ReadoutError(probabilities, atol=1e-08)
Bases: object
Readout error class for Qiskit Aer noise model.
Create a readout error for a noise model.
For an N-qubit readout error probabilities are entered as vectors:
probabilities[m] = [P(0|m), P(1|m), ..., P(2 ** N - 1|m)]where P(n|m) is the probability of recording a noisy measurement outcome as n given the true ideal measurement outcome was m, where n and m are integer representations of bit-strings.
Example: 1-qubit
probabilities[0] = [P("0"|"0"), P("1"|"0")]
probabilities[1] = [P("0"|"1"), P("1"|"1")]Example: 2-qubit
probabilities[0] = [P("00"|"00"), P("01"|"00"), P("10"|"00"), P("11"|"00")]
probabilities[1] = [P("00"|"01"), P("01"|"01"), P("10"|"01"), P("11"|"01")]
probabilities[2] = [P("00"|"10"), P("01"|"10"), P("10"|"10"), P("11"|"10")]
probabilities[3] = [P("00"|"11"), P("01"|"11"), P("10"|"11"), P("11"|"11")]Parameters
- probabilities (matrix) – List of outcome assignment probabilities.
- atol (double) – Threshold for checking probabilities are normalized (Default: 1e-8).
Raises
NoiseError – if an invalid argument is provided
Methods
compose
ReadoutError.compose(other, front=False)
Return the composition readout error other * self.
Note that for front=True this is equivalent to the ReadoutError.dot() method.
Parameters
- other (ReadoutError) – a readout error.
- front (bool) – If True return the reverse order composation self * other instead [default: False].
Returns
The composition readout error.
Return type
Raises
- NoiseError – if other is not a ReadoutError or has incompatible
- dimensions. –
copy
ReadoutError.copy()
Make a copy of current ReadoutError.
dot
ReadoutError.dot(other)
Return the composition readout error self * other.
Parameters
other (ReadoutError) – a readout error.
Returns
The composition readout error.
Return type
Raises
- NoiseError – if other is not a ReadoutError or has incompatible
- dimensions. –
expand
ReadoutError.expand(other)
Return the tensor product readout error self ⊗ other.
Parameters
other (ReadoutError) – a readout error.
Returns
the tensor product readout error other ⊗ self.
Return type
Raises
NoiseError – if other is not a ReadoutError.
ideal
ReadoutError.ideal()
Return True if current error object is an identity
power
ReadoutError.power(n)
Return the compose of the readout error with itself n times.
Parameters
n (int) – the number of times to compose with self (n>0).
Returns
the n-times composition channel.
Return type
Raises
NoiseError – if the power is not a positive integer.
set_atol
classmethod ReadoutError.set_atol(value)
Set the class default absolute tolerance parameter for float comparisons.
set_rtol
classmethod ReadoutError.set_rtol(value)
Set the class default relative tolerance parameter for float comparisons.
tensor
ReadoutError.tensor(other)
Return the tensor product readout error self ⊗ other.
Parameters
other (ReadoutError) – a readout error.
Returns
the tensor product readout error self ⊗ other.
Return type
Raises
NoiseError – if other is not a ReadoutError.
to_dict
ReadoutError.to_dict()
Return the current error as a dictionary.
to_instruction
ReadoutError.to_instruction()
Convert the ReadoutError to a circuit Instruction.
Attributes
atol
The default absolute tolerance parameter for float comparisons.
number_of_qubits
Return the number of qubits for the error.
probabilities
Return the readout error probabilities matrix.
rtol
The relative tolerance parameter for float comparisons.