227 lines
6.7 KiB
Plaintext
227 lines
6.7 KiB
Plaintext
---
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title: ReadoutError
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description: API reference for qiskit.providers.aer.noise.ReadoutError
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.providers.aer.noise.ReadoutError
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---
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# ReadoutError
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<Class id="qiskit.providers.aer.noise.ReadoutError" isDedicatedPage={true} github="https://github.com/qiskit/qiskit-aer/tree/stable/0.9/qiskit/providers/aer/noise/errors/readout_error.py" signature="ReadoutError(probabilities, atol=1e-08)" modifiers="class">
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Bases: `object`
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Readout error class for Qiskit Aer noise model.
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Create a readout error for a noise model.
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For an N-qubit readout error probabilities are entered as vectors:
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```python
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probabilities[m] = [P(0|m), P(1|m), ..., P(2 ** N - 1|m)]
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```
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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.
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**Example: 1-qubit**
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```python
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probabilities[0] = [P("0"|"0"), P("1"|"0")]
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probabilities[1] = [P("0"|"1"), P("1"|"1")]
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```
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**Example: 2-qubit**
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```python
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probabilities[0] = [P("00"|"00"), P("01"|"00"), P("10"|"00"), P("11"|"00")]
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probabilities[1] = [P("00"|"01"), P("01"|"01"), P("10"|"01"), P("11"|"01")]
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probabilities[2] = [P("00"|"10"), P("01"|"10"), P("10"|"10"), P("11"|"10")]
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probabilities[3] = [P("00"|"11"), P("01"|"11"), P("10"|"11"), P("11"|"11")]
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```
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**Parameters**
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* **probabilities** (*matrix*) – List of outcome assignment probabilities.
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* **atol** (*double*) – Threshold for checking probabilities are normalized (Default: 1e-8).
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## Methods
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### compose
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<Function id="qiskit.providers.aer.noise.ReadoutError.compose" signature="ReadoutError.compose(other, front=False)">
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Return the composition readout error other \* self.
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Note that for front=True this is equivalent to the [`ReadoutError.dot()`](qiskit.providers.aer.noise.ReadoutError#dot "qiskit.providers.aer.noise.ReadoutError.dot") method.
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**Parameters**
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* **other** ([*ReadoutError*](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")) – a readout error.
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* **front** (*bool*) – If True return the reverse order composation self \* other instead \[default: False].
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**Returns**
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The composition readout error.
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**Return type**
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[ReadoutError](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")
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**Raises**
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* **NoiseError** – if other is not a ReadoutError or has incompatible
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* **dimensions.** –
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</Function>
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### copy
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<Function id="qiskit.providers.aer.noise.ReadoutError.copy" signature="ReadoutError.copy()">
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Make a copy of current ReadoutError.
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</Function>
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### dot
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<Function id="qiskit.providers.aer.noise.ReadoutError.dot" signature="ReadoutError.dot(other)">
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Return the composition readout error self \* other.
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**Parameters**
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**other** ([*ReadoutError*](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")) – a readout error.
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**Returns**
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The composition readout error.
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**Return type**
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[ReadoutError](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")
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**Raises**
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* **NoiseError** – if other is not a ReadoutError or has incompatible
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* **dimensions.** –
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</Function>
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### expand
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<Function id="qiskit.providers.aer.noise.ReadoutError.expand" signature="ReadoutError.expand(other)">
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Return the tensor product readout error self ⊗ other.
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**Parameters**
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**other** ([*ReadoutError*](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")) – a readout error.
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**Returns**
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the tensor product readout error other ⊗ self.
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**Return type**
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[ReadoutError](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")
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**Raises**
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**NoiseError** – if other is not a ReadoutError.
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</Function>
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### ideal
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<Function id="qiskit.providers.aer.noise.ReadoutError.ideal" signature="ReadoutError.ideal()">
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Return True if current error object is an identity
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</Function>
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### power
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<Function id="qiskit.providers.aer.noise.ReadoutError.power" signature="ReadoutError.power(n)">
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Return the compose of the readout error with itself n times.
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**Parameters**
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**n** (*int*) – the number of times to compose with self (n>0).
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**Returns**
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the n-times composition channel.
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**Return type**
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[ReadoutError](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")
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**Raises**
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**NoiseError** – if the power is not a positive integer.
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</Function>
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### set\_atol
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<Function id="qiskit.providers.aer.noise.ReadoutError.set_atol" signature="ReadoutError.set_atol(value)" modifiers="classmethod">
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Set the class default absolute tolerance parameter for float comparisons.
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</Function>
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### set\_rtol
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<Function id="qiskit.providers.aer.noise.ReadoutError.set_rtol" signature="ReadoutError.set_rtol(value)" modifiers="classmethod">
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Set the class default relative tolerance parameter for float comparisons.
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</Function>
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### tensor
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<Function id="qiskit.providers.aer.noise.ReadoutError.tensor" signature="ReadoutError.tensor(other)">
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Return the tensor product readout error self ⊗ other.
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**Parameters**
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**other** ([*ReadoutError*](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")) – a readout error.
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**Returns**
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the tensor product readout error self ⊗ other.
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**Return type**
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[ReadoutError](qiskit.providers.aer.noise.ReadoutError "qiskit.providers.aer.noise.ReadoutError")
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**Raises**
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**NoiseError** – if other is not a ReadoutError.
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</Function>
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### to\_dict
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<Function id="qiskit.providers.aer.noise.ReadoutError.to_dict" signature="ReadoutError.to_dict()">
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Return the current error as a dictionary.
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</Function>
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### to\_instruction
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<Function id="qiskit.providers.aer.noise.ReadoutError.to_instruction" signature="ReadoutError.to_instruction()">
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Convert the ReadoutError to a circuit Instruction.
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</Function>
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## Attributes
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### atol
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<Attribute id="qiskit.providers.aer.noise.ReadoutError.atol">
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The default absolute tolerance parameter for float comparisons.
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</Attribute>
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### number\_of\_qubits
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<Attribute id="qiskit.providers.aer.noise.ReadoutError.number_of_qubits">
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Return the number of qubits for the error.
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</Attribute>
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### probabilities
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<Attribute id="qiskit.providers.aer.noise.ReadoutError.probabilities">
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Return the readout error probabilities matrix.
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</Attribute>
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### rtol
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<Attribute id="qiskit.providers.aer.noise.ReadoutError.rtol">
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The relative tolerance parameter for float comparisons.
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</Attribute>
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</Class>
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