224 lines
8.6 KiB
Plaintext
224 lines
8.6 KiB
Plaintext
---
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title: GaussianSquare
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description: API reference for qiskit.pulse.library.GaussianSquare
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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.pulse.library.GaussianSquare
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---
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# GaussianSquare
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<Class id="qiskit.pulse.library.GaussianSquare" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.21/qiskit/pulse/library/symbolic_pulses.py" signature="GaussianSquare(duration, amp, sigma, width=None, risefall_sigma_ratio=None, name=None, limit_amplitude=None)" modifiers="class">
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Bases: [`qiskit.pulse.library.symbolic_pulses.SymbolicPulse`](qiskit.pulse.library.SymbolicPulse "qiskit.pulse.library.symbolic_pulses.SymbolicPulse")
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A square pulse with a Gaussian shaped risefall on both sides lifted such that its first sample is zero.
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Exactly one of the `risefall_sigma_ratio` and `width` parameters has to be specified.
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If `risefall_sigma_ratio` is not None and `width` is None:
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$$
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\begin{split}\text{risefall} &= \text{risefall_sigma_ratio} \times \text{sigma}\\
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\text{width} &= \text{duration} - 2 \times \text{risefall}\end{split}
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$$
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If `width` is not None and `risefall_sigma_ratio` is None:
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$$
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\text{risefall} = \frac{\text{duration} - \text{width}}{2}
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$$
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In both cases, the lifted gaussian square pulse $f'(x)$ is defined as:
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$$
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\begin{split}f'(x) &= \begin{cases} \exp\biggl(-\frac12 \frac{(x - \text{risefall})^2}{\text{sigma}^2}\biggr) & x < \text{risefall}\\
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1 & \text{risefall} \le x < \text{risefall} + \text{width}\\
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\exp\biggl(-\frac12 \frac{{\bigl(x - (\text{risefall} + \text{width})\bigr)}^2} {\text{sigma}^2} \biggr) & \text{risefall} + \text{width} \le x \end{cases}\\
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f(x) &= \text{amp} \times \frac{f'(x) - f'(-1)}{1-f'(-1)}, \quad 0 \le x < \text{duration}\end{split}
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$$
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where $f'(x)$ is the gaussian square waveform without lifting or amplitude scaling.
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Create new pulse instance.
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**Parameters**
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* **duration** (`Union`\[`int`, [`ParameterExpression`](qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")]) – Pulse length in terms of the sampling period dt.
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* **amp** (`Union`\[`complex`, [`ParameterExpression`](qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")]) – The amplitude of the Gaussian and of the square pulse.
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* **sigma** (`Union`\[`float`, [`ParameterExpression`](qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")]) – A measure of how wide or narrow the Gaussian risefall is; see the class docstring for more details.
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* **width** (`Union`\[`float`, [`ParameterExpression`](qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression"), `None`]) – The duration of the embedded square pulse.
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* **risefall\_sigma\_ratio** (`Union`\[`float`, [`ParameterExpression`](qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression"), `None`]) – The ratio of each risefall duration to sigma.
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* **name** (`Optional`\[`str`]) – Display name for this pulse envelope.
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* **limit\_amplitude** (`Optional`\[`bool`]) – If `True`, then limit the amplitude of the waveform to 1. The default is `True` and the amplitude is constrained to 1.
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**Raises**
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[**PulseError**](pulse#qiskit.pulse.PulseError "qiskit.pulse.PulseError") – When width and risefall\_sigma\_ratio are both empty or both non-empty.
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## Methods
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### draw
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<Function id="qiskit.pulse.library.GaussianSquare.draw" signature="GaussianSquare.draw(style=None, backend=None, time_range=None, time_unit='dt', show_waveform_info=True, plotter='mpl2d', axis=None)">
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Plot the interpolated envelope of pulse.
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**Parameters**
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* **style** (`Optional`\[`Dict`\[`str`, `Any`]]) – Stylesheet options. This can be dictionary or preset stylesheet classes. See `IQXStandard`, `IQXSimple`, and `IQXDebugging` for details of preset stylesheets.
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* **backend** (*Optional\[BaseBackend]*) – Backend object to play the input pulse program. If provided, the plotter may use to make the visualization hardware aware.
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* **time\_range** (`Optional`\[`Tuple`\[`int`, `int`]]) – Set horizontal axis limit. Tuple `(tmin, tmax)`.
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* **time\_unit** (`str`) – The unit of specified time range either `dt` or `ns`. The unit of `ns` is available only when `backend` object is provided.
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* **show\_waveform\_info** (`bool`) – Show waveform annotations, i.e. name, of waveforms. Set `True` to show additional information about waveforms.
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* **plotter** (`str`) –
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Name of plotter API to generate an output image. One of following APIs should be specified:
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```python
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mpl2d: Matplotlib API for 2D image generation.
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Matplotlib API to generate 2D image. Charts are placed along y axis with
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vertical offset. This API takes matplotlib.axes.Axes as `axis` input.
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```
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axis and style kwargs may depend on the plotter.
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* **axis** (`Optional`\[`Any`]) – Arbitrary object passed to the plotter. If this object is provided, the plotters use a given `axis` instead of internally initializing a figure object. This object format depends on the plotter. See plotter argument for details.
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**Returns**
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Visualization output data. The returned data type depends on the `plotter`. If matplotlib family is specified, this will be a `matplotlib.pyplot.Figure` data.
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</Function>
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### get\_waveform
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<Function id="qiskit.pulse.library.GaussianSquare.get_waveform" signature="GaussianSquare.get_waveform()">
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Return a Waveform with samples filled according to the formula that the pulse represents and the parameter values it contains.
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Since the returned array is a discretized time series of the continuous function, this method uses a midpoint sampler. For `duration`, return:
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$$
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\{f(t+0.5) \in \mathbb{C} | t \in \mathbb{Z} \wedge 0<=t<\texttt{duration}\}
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$$
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**Return type**
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[`Waveform`](qiskit.pulse.library.Waveform "qiskit.pulse.library.waveform.Waveform")
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**Returns**
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A waveform representation of this pulse.
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**Raises**
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* [**PulseError**](pulse#qiskit.pulse.PulseError "qiskit.pulse.PulseError") – When parameters are not assigned.
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* [**PulseError**](pulse#qiskit.pulse.PulseError "qiskit.pulse.PulseError") – When expression for pulse envelope is not assigned.
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</Function>
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### is\_parameterized
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<Function id="qiskit.pulse.library.GaussianSquare.is_parameterized" signature="GaussianSquare.is_parameterized()">
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Return True iff the instruction is parameterized.
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**Return type**
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`bool`
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</Function>
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### validate\_parameters
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<Function id="qiskit.pulse.library.GaussianSquare.validate_parameters" signature="GaussianSquare.validate_parameters()">
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Validate parameters.
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**Raises**
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[**PulseError**](pulse#qiskit.pulse.PulseError "qiskit.pulse.PulseError") – If the parameters passed are not valid.
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**Return type**
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`None`
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</Function>
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## Attributes
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### constraints
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<Attribute id="qiskit.pulse.library.GaussianSquare.constraints">
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Return symbolic expression for the pulse parameter constraints.
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**Return type**
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`Expr`
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</Attribute>
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### duration
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<Attribute id="qiskit.pulse.library.GaussianSquare.duration" />
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### envelope
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<Attribute id="qiskit.pulse.library.GaussianSquare.envelope">
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Return symbolic expression for the pulse envelope.
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**Return type**
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`Expr`
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</Attribute>
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### id
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<Attribute id="qiskit.pulse.library.GaussianSquare.id">
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Unique identifier for this pulse.
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**Return type**
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`int`
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</Attribute>
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### limit\_amplitude
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<Attribute id="qiskit.pulse.library.GaussianSquare.limit_amplitude" attributeValue="True" />
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### name
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<Attribute id="qiskit.pulse.library.GaussianSquare.name" />
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### parameters
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<Attribute id="qiskit.pulse.library.GaussianSquare.parameters">
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**Return type**
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`Dict`\[`str`, `Any`]
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</Attribute>
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### pulse\_type
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<Attribute id="qiskit.pulse.library.GaussianSquare.pulse_type">
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Return display name of the pulse shape.
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**Return type**
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`str`
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</Attribute>
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### risefall\_sigma\_ratio
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<Attribute id="qiskit.pulse.library.GaussianSquare.risefall_sigma_ratio">
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Return risefall\_sigma\_ratio. This is auxiliary parameter to define width.
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</Attribute>
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### valid\_amp\_conditions
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<Attribute id="qiskit.pulse.library.GaussianSquare.valid_amp_conditions">
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Return symbolic expression for the pulse amplitude constraints.
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**Return type**
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`Expr`
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</Attribute>
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</Class>
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