251 lines
8.5 KiB
Plaintext
251 lines
8.5 KiB
Plaintext
---
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title: AQGD (v0.29)
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description: API reference for qiskit.algorithms.optimizers.AQGD in qiskit v0.29
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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.algorithms.optimizers.AQGD
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---
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# AQGD
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<Class id="qiskit.algorithms.optimizers.AQGD" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.18/qiskit/algorithms/optimizers/aqgd.py" signature="AQGD(maxiter=1000, eta=1.0, tol=1e-06, momentum=0.25, param_tol=1e-06, averaging=10)" modifiers="class">
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Bases: `qiskit.algorithms.optimizers.optimizer.Optimizer`
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Analytic Quantum Gradient Descent (AQGD) with Epochs optimizer. Performs gradient descent optimization with a momentum term, analytic gradients, and customized step length schedule for parameterized quantum gates, i.e. Pauli Rotations. See, for example:
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* K. Mitarai, M. Negoro, M. Kitagawa, and K. Fujii. (2018). Quantum circuit learning. Phys. Rev. A 98, 032309. [https://arxiv.org/abs/1803.00745](https://arxiv.org/abs/1803.00745)
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* Maria Schuld, Ville Bergholm, Christian Gogolin, Josh Izaac, Nathan Killoran. (2019). Evaluating analytic gradients on quantum hardware. Phys. Rev. A 99, 032331. [https://arxiv.org/abs/1811.11184](https://arxiv.org/abs/1811.11184)
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for further details on analytic gradients of parameterized quantum gates.
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Gradients are computed “analytically” using the quantum circuit when evaluating the objective function.
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Performs Analytical Quantum Gradient Descent (AQGD) with Epochs.
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**Parameters**
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* **maxiter** (`Union`\[`int`, `List`\[`int`]]) – Maximum number of iterations (full gradient steps)
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* **eta** (`Union`\[`float`, `List`\[`float`]]) – The coefficient of the gradient update. Increasing this value results in larger step sizes: param = previous\_param - eta \* deriv
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* **tol** (`float`) – Tolerance for change in windowed average of objective values. Convergence occurs when either objective tolerance is met OR parameter tolerance is met.
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* **momentum** (`Union`\[`float`, `List`\[`float`]]) – Bias towards the previous gradient momentum in current update. Must be within the bounds: \[0,1)
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* **param\_tol** (`float`) – Tolerance for change in norm of parameters.
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* **averaging** (`int`) – Length of window over which to average objective values for objective convergence criterion
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**Raises**
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[**AlgorithmError**](qiskit.algorithms.AlgorithmError "qiskit.algorithms.AlgorithmError") – If the length of `maxiter`, momentum\`, and `eta` is not the same.
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## Methods
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<span id="qiskit-algorithms-optimizers-aqgd-get-support-level" />
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### get\_support\_level
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<Function id="qiskit.algorithms.optimizers.AQGD.get_support_level" signature="AQGD.get_support_level()">
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Support level dictionary
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**Returns**
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**gradient, bounds and initial point**
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support information that is ignored/required.
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**Return type**
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Dict\[str, int]
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-gradient-num-diff" />
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### gradient\_num\_diff
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<Function id="qiskit.algorithms.optimizers.AQGD.gradient_num_diff" signature="AQGD.gradient_num_diff(x_center, f, epsilon, max_evals_grouped=1)" modifiers="static">
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We compute the gradient with the numeric differentiation in the parallel way, around the point x\_center.
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**Parameters**
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* **x\_center** (*ndarray*) – point around which we compute the gradient
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* **f** (*func*) – the function of which the gradient is to be computed.
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* **epsilon** (*float*) – the epsilon used in the numeric differentiation.
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* **max\_evals\_grouped** (*int*) – max evals grouped
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**Returns**
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the gradient computed
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**Return type**
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grad
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-optimize" />
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### optimize
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<Function id="qiskit.algorithms.optimizers.AQGD.optimize" signature="AQGD.optimize(num_vars, objective_function, gradient_function=None, variable_bounds=None, initial_point=None)">
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Perform optimization.
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**Parameters**
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* **num\_vars** (*int*) – Number of parameters to be optimized.
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* **objective\_function** (*callable*) – A function that computes the objective function.
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* **gradient\_function** (*callable*) – A function that computes the gradient of the objective function, or None if not available.
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* **variable\_bounds** (*list\[(float, float)]*) – List of variable bounds, given as pairs (lower, upper). None means unbounded.
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* **initial\_point** (*numpy.ndarray\[float]*) – Initial point.
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**Return type**
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`Tuple`\[`ndarray`, `float`, `int`]
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**Returns**
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**point, value, nfev**
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point: is a 1D numpy.ndarray\[float] containing the solution value: is a float with the objective function value nfev: number of objective function calls made if available or None
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**Raises**
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**ValueError** – invalid input
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-print-options" />
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### print\_options
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<Function id="qiskit.algorithms.optimizers.AQGD.print_options" signature="AQGD.print_options()">
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Print algorithm-specific options.
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-set-max-evals-grouped" />
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### set\_max\_evals\_grouped
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<Function id="qiskit.algorithms.optimizers.AQGD.set_max_evals_grouped" signature="AQGD.set_max_evals_grouped(limit)">
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Set max evals grouped
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-set-options" />
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### set\_options
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<Function id="qiskit.algorithms.optimizers.AQGD.set_options" signature="AQGD.set_options(**kwargs)">
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Sets or updates values in the options dictionary.
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The options dictionary may be used internally by a given optimizer to pass additional optional values for the underlying optimizer/optimization function used. The options dictionary may be initially populated with a set of key/values when the given optimizer is constructed.
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**Parameters**
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**kwargs** (*dict*) – options, given as name=value.
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</Function>
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<span id="qiskit-algorithms-optimizers-aqgd-wrap-function" />
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### wrap\_function
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<Function id="qiskit.algorithms.optimizers.AQGD.wrap_function" signature="AQGD.wrap_function(function, args)" modifiers="static">
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Wrap the function to implicitly inject the args at the call of the function.
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**Parameters**
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* **function** (*func*) – the target function
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* **args** (*tuple*) – the args to be injected
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**Returns**
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wrapper
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**Return type**
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function\_wrapper
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</Function>
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## Attributes
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### bounds\_support\_level
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<Attribute id="qiskit.algorithms.optimizers.AQGD.bounds_support_level">
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Returns bounds support level
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</Attribute>
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### gradient\_support\_level
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<Attribute id="qiskit.algorithms.optimizers.AQGD.gradient_support_level">
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Returns gradient support level
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</Attribute>
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### initial\_point\_support\_level
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<Attribute id="qiskit.algorithms.optimizers.AQGD.initial_point_support_level">
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Returns initial point support level
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</Attribute>
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### is\_bounds\_ignored
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_bounds_ignored">
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Returns is bounds ignored
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</Attribute>
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### is\_bounds\_required
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_bounds_required">
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Returns is bounds required
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</Attribute>
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### is\_bounds\_supported
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_bounds_supported">
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Returns is bounds supported
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</Attribute>
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### is\_gradient\_ignored
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_gradient_ignored">
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Returns is gradient ignored
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</Attribute>
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### is\_gradient\_required
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_gradient_required">
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Returns is gradient required
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</Attribute>
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### is\_gradient\_supported
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_gradient_supported">
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Returns is gradient supported
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</Attribute>
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### is\_initial\_point\_ignored
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_initial_point_ignored">
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Returns is initial point ignored
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</Attribute>
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### is\_initial\_point\_required
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_initial_point_required">
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Returns is initial point required
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</Attribute>
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### is\_initial\_point\_supported
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<Attribute id="qiskit.algorithms.optimizers.AQGD.is_initial_point_supported">
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Returns is initial point supported
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</Attribute>
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### setting
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<Attribute id="qiskit.algorithms.optimizers.AQGD.setting">
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Return setting
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</Attribute>
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### settings
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<Attribute id="qiskit.algorithms.optimizers.AQGD.settings">
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**Return type**
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`Dict`\[`str`, `Any`]
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</Attribute>
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</Class>
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