157 lines
7.4 KiB
Plaintext
157 lines
7.4 KiB
Plaintext
---
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title: MultiStartOptimizer
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description: API reference for qiskit.optimization.algorithms.MultiStartOptimizer
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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.optimization.algorithms.MultiStartOptimizer
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---
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# qiskit.optimization.algorithms.MultiStartOptimizer
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<Class id="qiskit.optimization.algorithms.MultiStartOptimizer" isDedicatedPage={true} github="https://github.com/qiskit-community/qiskit-aqua/tree/stable/0.9/qiskit/optimization/algorithms/multistart_optimizer.py" signature="MultiStartOptimizer(trials=1, clip=100.0)" modifiers="class">
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An abstract class that implements multi start optimization and should be sub-classed by other optimizers.
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Constructs an instance of this optimizer.
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**Parameters**
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* **trials** (`int`) – The number of trials for multi-start method. The first trial is solved with the initial guess of zero. If more than one trial is specified then initial guesses are uniformly drawn from `[lowerbound, upperbound]` with potential clipping.
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* **clip** (`float`) – Clipping parameter for the initial guesses in the multi-start method. If a variable is unbounded then the lower bound and/or upper bound are replaced with the `-clip` or `clip` values correspondingly for the initial guesses.
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### \_\_init\_\_
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<Function id="qiskit.optimization.algorithms.MultiStartOptimizer.__init__" signature="__init__(trials=1, clip=100.0)">
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Constructs an instance of this optimizer.
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**Parameters**
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* **trials** (`int`) – The number of trials for multi-start method. The first trial is solved with the initial guess of zero. If more than one trial is specified then initial guesses are uniformly drawn from `[lowerbound, upperbound]` with potential clipping.
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* **clip** (`float`) – Clipping parameter for the initial guesses in the multi-start method. If a variable is unbounded then the lower bound and/or upper bound are replaced with the `-clip` or `clip` values correspondingly for the initial guesses.
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</Function>
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## Methods
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| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------- |
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| [`__init__`](#qiskit.optimization.algorithms.MultiStartOptimizer.__init__ "qiskit.optimization.algorithms.MultiStartOptimizer.__init__")(\[trials, clip]) | Constructs an instance of this optimizer. |
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| [`get_compatibility_msg`](#qiskit.optimization.algorithms.MultiStartOptimizer.get_compatibility_msg "qiskit.optimization.algorithms.MultiStartOptimizer.get_compatibility_msg")(problem) | Checks whether a given problem can be solved with the optimizer implementing this method. |
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| [`is_compatible`](#qiskit.optimization.algorithms.MultiStartOptimizer.is_compatible "qiskit.optimization.algorithms.MultiStartOptimizer.is_compatible")(problem) | Checks whether a given problem can be solved with the optimizer implementing this method. |
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| [`multi_start_solve`](#qiskit.optimization.algorithms.MultiStartOptimizer.multi_start_solve "qiskit.optimization.algorithms.MultiStartOptimizer.multi_start_solve")(minimize, problem) | Applies a multi start method given a local optimizer. |
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| [`solve`](#qiskit.optimization.algorithms.MultiStartOptimizer.solve "qiskit.optimization.algorithms.MultiStartOptimizer.solve")(problem) | Tries to solves the given problem using the optimizer. |
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## Attributes
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| ---------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------ |
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| [`clip`](#qiskit.optimization.algorithms.MultiStartOptimizer.clip "qiskit.optimization.algorithms.MultiStartOptimizer.clip") | Returns the clip value for this optimizer. |
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| [`trials`](#qiskit.optimization.algorithms.MultiStartOptimizer.trials "qiskit.optimization.algorithms.MultiStartOptimizer.trials") | Returns the number of trials for this optimizer. |
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### clip
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<Attribute id="qiskit.optimization.algorithms.MultiStartOptimizer.clip">
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Returns the clip value for this optimizer.
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**Return type**
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`float`
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**Returns**
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The clip value.
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</Attribute>
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### get\_compatibility\_msg
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<Function id="qiskit.optimization.algorithms.MultiStartOptimizer.get_compatibility_msg" signature="get_compatibility_msg(problem)" modifiers="abstract">
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Checks whether a given problem can be solved with the optimizer implementing this method.
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**Parameters**
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**problem** (`QuadraticProgram`) – The optimization problem to check compatibility.
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**Return type**
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`str`
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**Returns**
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Returns the incompatibility message. If the message is empty no issues were found.
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</Function>
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### is\_compatible
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<Function id="qiskit.optimization.algorithms.MultiStartOptimizer.is_compatible" signature="is_compatible(problem)">
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Checks whether a given problem can be solved with the optimizer implementing this method.
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**Parameters**
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**problem** (`QuadraticProgram`) – The optimization problem to check compatibility.
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**Return type**
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`bool`
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**Returns**
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Returns True if the problem is compatible, False otherwise.
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</Function>
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### multi\_start\_solve
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<Function id="qiskit.optimization.algorithms.MultiStartOptimizer.multi_start_solve" signature="multi_start_solve(minimize, problem)">
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Applies a multi start method given a local optimizer.
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**Parameters**
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* **minimize** (`Callable`\[\[`ndarray`], `Tuple`\[`ndarray`, `Any`]]) – A callable object that minimizes the problem specified
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* **problem** (`QuadraticProgram`) – A problem to solve
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**Return type**
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`OptimizationResult`
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**Returns**
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The result of the multi start algorithm applied to the problem.
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</Function>
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### solve
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<Function id="qiskit.optimization.algorithms.MultiStartOptimizer.solve" signature="solve(problem)" modifiers="abstract">
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Tries to solves the given problem using the optimizer.
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Runs the optimizer to try to solve the optimization problem.
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**Parameters**
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**problem** (`QuadraticProgram`) – The problem to be solved.
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**Return type**
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`OptimizationResult`
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**Returns**
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The result of the optimizer applied to the problem.
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**Raises**
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[**QiskitOptimizationError**](qiskit.optimization.QiskitOptimizationError "qiskit.optimization.QiskitOptimizationError") – If the problem is incompatible with the optimizer.
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</Function>
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### trials
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<Attribute id="qiskit.optimization.algorithms.MultiStartOptimizer.trials">
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Returns the number of trials for this optimizer.
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**Return type**
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`int`
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**Returns**
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The number of trials.
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</Attribute>
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</Class>
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