219 lines
7.1 KiB
Plaintext
219 lines
7.1 KiB
Plaintext
---
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title: SNOBFIT
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description: API reference for qiskit.algorithms.optimizers.SNOBFIT
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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.SNOBFIT
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---
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# SNOBFIT
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<Class id="qiskit.algorithms.optimizers.SNOBFIT" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.20/qiskit/algorithms/optimizers/snobfit.py" signature="SNOBFIT(maxiter=1000, maxfail=10, maxmp=None, verbose=False)" modifiers="class">
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Bases: `qiskit.algorithms.optimizers.optimizer.Optimizer`
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Stable Noisy Optimization by Branch and FIT algorithm.
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SnobFit is used for the optimization of derivative-free, noisy objective functions providing robust and fast solutions of problems with continuous variables varying within bound.
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Uses skquant.opt installed with pip install scikit-quant. For further detail, please refer to [https://github.com/scikit-quant/scikit-quant](https://github.com/scikit-quant/scikit-quant) and [https://qat4chem.lbl.gov/software](https://qat4chem.lbl.gov/software).
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**Parameters**
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* **maxiter** (`int`) – Maximum number of function evaluations.
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* **maxmp** (`Optional`\[`int`]) – Maximum number of model points requested for the local fit. Default = 2 \* number of parameters + 6 set to this value when None.
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* **maxfail** (`int`) – Maximum number of failures to improve the solution. Stops the algorithm after maxfail is reached.
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* **verbose** (`bool`) – Provide verbose (debugging) output.
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**Raises**
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**MissingOptionalLibraryError** – scikit-quant or SQSnobFit not installed
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## Methods
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### get\_support\_level
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.get_support_level" signature="SNOBFIT.get_support_level()">
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Returns support level dictionary.
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</Function>
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### gradient\_num\_diff
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.gradient_num_diff" signature="SNOBFIT.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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### minimize
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.minimize" signature="SNOBFIT.minimize(fun, x0, jac=None, bounds=None)">
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Minimize the scalar function.
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**Parameters**
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* **fun** (`Callable`\[\[`Union`\[`float`, `ndarray`]], `float`]) – The scalar function to minimize.
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* **x0** (`Union`\[`float`, `ndarray`]) – The initial point for the minimization.
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* **jac** (`Optional`\[`Callable`\[\[`Union`\[`float`, `ndarray`]], `Union`\[`float`, `ndarray`]]]) – The gradient of the scalar function `fun`.
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* **bounds** (`Optional`\[`List`\[`Tuple`\[`float`, `float`]]]) – Bounds for the variables of `fun`. This argument might be ignored if the optimizer does not support bounds.
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**Return type**
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`OptimizerResult`
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**Returns**
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The result of the optimization, containing e.g. the result as attribute `x`.
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</Function>
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### optimize
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.optimize" signature="SNOBFIT.optimize(num_vars, objective_function, gradient_function=None, variable_bounds=None, initial_point=None)">
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Runs the optimization.
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</Function>
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### print\_options
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.print_options" signature="SNOBFIT.print_options()">
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Print algorithm-specific options.
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</Function>
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### set\_max\_evals\_grouped
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.set_max_evals_grouped" signature="SNOBFIT.set_max_evals_grouped(limit)">
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Set max evals grouped
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</Function>
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### set\_options
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.set_options" signature="SNOBFIT.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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### wrap\_function
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<Function id="qiskit.algorithms.optimizers.SNOBFIT.wrap_function" signature="SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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.SNOBFIT.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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