248 lines
15 KiB
Plaintext
248 lines
15 KiB
Plaintext
---
|
||
title: NELDER_MEAD (v0.26)
|
||
description: API reference for qiskit.aqua.components.optimizers.NELDER_MEAD in qiskit v0.26
|
||
in_page_toc_min_heading_level: 1
|
||
python_api_type: class
|
||
python_api_name: qiskit.aqua.components.optimizers.NELDER_MEAD
|
||
---
|
||
|
||
<span id="qiskit-aqua-components-optimizers-nelder-mead" />
|
||
|
||
# qiskit.aqua.components.optimizers.NELDER\_MEAD
|
||
|
||
<Class id="qiskit.aqua.components.optimizers.NELDER_MEAD" isDedicatedPage={true} github="https://github.com/qiskit-community/qiskit-aqua/tree/stable/0.9/qiskit/aqua/components/optimizers/nelder_mead.py" signature="NELDER_MEAD(maxiter=None, maxfev=1000, disp=False, xatol=0.0001, tol=None, adaptive=False)" modifiers="class">
|
||
Nelder-Mead optimizer.
|
||
|
||
The Nelder-Mead algorithm performs unconstrained optimization; it ignores bounds or constraints. It is used to find the minimum or maximum of an objective function in a multidimensional space. It is based on the Simplex algorithm. Nelder-Mead is robust in many applications, especially when the first and second derivatives of the objective function are not known.
|
||
|
||
However, if the numerical computation of the derivatives can be trusted to be accurate, other algorithms using the first and/or second derivatives information might be preferred to Nelder-Mead for their better performance in the general case, especially in consideration of the fact that the Nelder–Mead technique is a heuristic search method that can converge to non-stationary points.
|
||
|
||
Uses scipy.optimize.minimize Nelder-Mead. For further detail, please refer to See [https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.minimize.html](https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.minimize.html)
|
||
|
||
**Parameters**
|
||
|
||
* **maxiter** (`Optional`\[`int`]) – Maximum allowed number of iterations. If both maxiter and maxfev are set, minimization will stop at the first reached.
|
||
* **maxfev** (`int`) – Maximum allowed number of function evaluations. If both maxiter and maxfev are set, minimization will stop at the first reached.
|
||
* **disp** (`bool`) – Set to True to print convergence messages.
|
||
* **xatol** (`float`) – Absolute error in xopt between iterations that is acceptable for convergence.
|
||
* **tol** (`Optional`\[`float`]) – Tolerance for termination.
|
||
* **adaptive** (`bool`) – Adapt algorithm parameters to dimensionality of problem.
|
||
|
||
### \_\_init\_\_
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.__init__" signature="__init__(maxiter=None, maxfev=1000, disp=False, xatol=0.0001, tol=None, adaptive=False)">
|
||
**Parameters**
|
||
|
||
* **maxiter** (`Optional`\[`int`]) – Maximum allowed number of iterations. If both maxiter and maxfev are set, minimization will stop at the first reached.
|
||
* **maxfev** (`int`) – Maximum allowed number of function evaluations. If both maxiter and maxfev are set, minimization will stop at the first reached.
|
||
* **disp** (`bool`) – Set to True to print convergence messages.
|
||
* **xatol** (`float`) – Absolute error in xopt between iterations that is acceptable for convergence.
|
||
* **tol** (`Optional`\[`float`]) – Tolerance for termination.
|
||
* **adaptive** (`bool`) – Adapt algorithm parameters to dimensionality of problem.
|
||
</Function>
|
||
|
||
## Methods
|
||
|
||
| | |
|
||
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- |
|
||
| [`__init__`](#qiskit.aqua.components.optimizers.NELDER_MEAD.__init__ "qiskit.aqua.components.optimizers.NELDER_MEAD.__init__")(\[maxiter, maxfev, disp, xatol, …]) | **type maxiter**`Optional`\[`int`] |
|
||
| [`get_support_level`](#qiskit.aqua.components.optimizers.NELDER_MEAD.get_support_level "qiskit.aqua.components.optimizers.NELDER_MEAD.get_support_level")() | Return support level dictionary |
|
||
| [`gradient_num_diff`](#qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_num_diff "qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_num_diff")(x\_center, f, epsilon\[, …]) | We compute the gradient with the numeric differentiation in the parallel way, around the point x\_center. |
|
||
| [`optimize`](#qiskit.aqua.components.optimizers.NELDER_MEAD.optimize "qiskit.aqua.components.optimizers.NELDER_MEAD.optimize")(num\_vars, objective\_function\[, …]) | Perform optimization. |
|
||
| [`print_options`](#qiskit.aqua.components.optimizers.NELDER_MEAD.print_options "qiskit.aqua.components.optimizers.NELDER_MEAD.print_options")() | Print algorithm-specific options. |
|
||
| [`set_max_evals_grouped`](#qiskit.aqua.components.optimizers.NELDER_MEAD.set_max_evals_grouped "qiskit.aqua.components.optimizers.NELDER_MEAD.set_max_evals_grouped")(limit) | Set max evals grouped |
|
||
| [`set_options`](#qiskit.aqua.components.optimizers.NELDER_MEAD.set_options "qiskit.aqua.components.optimizers.NELDER_MEAD.set_options")(\*\*kwargs) | Sets or updates values in the options dictionary. |
|
||
| [`wrap_function`](#qiskit.aqua.components.optimizers.NELDER_MEAD.wrap_function "qiskit.aqua.components.optimizers.NELDER_MEAD.wrap_function")(function, args) | Wrap the function to implicitly inject the args at the call of the function. |
|
||
|
||
## Attributes
|
||
|
||
| | |
|
||
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------- |
|
||
| [`bounds_support_level`](#qiskit.aqua.components.optimizers.NELDER_MEAD.bounds_support_level "qiskit.aqua.components.optimizers.NELDER_MEAD.bounds_support_level") | Returns bounds support level |
|
||
| [`gradient_support_level`](#qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_support_level "qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_support_level") | Returns gradient support level |
|
||
| [`initial_point_support_level`](#qiskit.aqua.components.optimizers.NELDER_MEAD.initial_point_support_level "qiskit.aqua.components.optimizers.NELDER_MEAD.initial_point_support_level") | Returns initial point support level |
|
||
| [`is_bounds_ignored`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_ignored "qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_ignored") | Returns is bounds ignored |
|
||
| [`is_bounds_required`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_required "qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_required") | Returns is bounds required |
|
||
| [`is_bounds_supported`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_supported "qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_supported") | Returns is bounds supported |
|
||
| [`is_gradient_ignored`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_ignored "qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_ignored") | Returns is gradient ignored |
|
||
| [`is_gradient_required`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_required "qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_required") | Returns is gradient required |
|
||
| [`is_gradient_supported`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_supported "qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_supported") | Returns is gradient supported |
|
||
| [`is_initial_point_ignored`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_ignored "qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_ignored") | Returns is initial point ignored |
|
||
| [`is_initial_point_required`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_required "qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_required") | Returns is initial point required |
|
||
| [`is_initial_point_supported`](#qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_supported "qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_supported") | Returns is initial point supported |
|
||
| [`setting`](#qiskit.aqua.components.optimizers.NELDER_MEAD.setting "qiskit.aqua.components.optimizers.NELDER_MEAD.setting") | Return setting |
|
||
|
||
### bounds\_support\_level
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.bounds_support_level">
|
||
Returns bounds support level
|
||
</Attribute>
|
||
|
||
### get\_support\_level
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.get_support_level" signature="get_support_level()">
|
||
Return support level dictionary
|
||
</Function>
|
||
|
||
### gradient\_num\_diff
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_num_diff" signature="gradient_num_diff(x_center, f, epsilon, max_evals_grouped=1)" modifiers="static">
|
||
We compute the gradient with the numeric differentiation in the parallel way, around the point x\_center.
|
||
|
||
**Parameters**
|
||
|
||
* **x\_center** (*ndarray*) – point around which we compute the gradient
|
||
* **f** (*func*) – the function of which the gradient is to be computed.
|
||
* **epsilon** (*float*) – the epsilon used in the numeric differentiation.
|
||
* **max\_evals\_grouped** (*int*) – max evals grouped
|
||
|
||
**Returns**
|
||
|
||
the gradient computed
|
||
|
||
**Return type**
|
||
|
||
grad
|
||
</Function>
|
||
|
||
### gradient\_support\_level
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.gradient_support_level">
|
||
Returns gradient support level
|
||
</Attribute>
|
||
|
||
### initial\_point\_support\_level
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.initial_point_support_level">
|
||
Returns initial point support level
|
||
</Attribute>
|
||
|
||
### is\_bounds\_ignored
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_ignored">
|
||
Returns is bounds ignored
|
||
</Attribute>
|
||
|
||
### is\_bounds\_required
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_required">
|
||
Returns is bounds required
|
||
</Attribute>
|
||
|
||
### is\_bounds\_supported
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_bounds_supported">
|
||
Returns is bounds supported
|
||
</Attribute>
|
||
|
||
### is\_gradient\_ignored
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_ignored">
|
||
Returns is gradient ignored
|
||
</Attribute>
|
||
|
||
### is\_gradient\_required
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_required">
|
||
Returns is gradient required
|
||
</Attribute>
|
||
|
||
### is\_gradient\_supported
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_gradient_supported">
|
||
Returns is gradient supported
|
||
</Attribute>
|
||
|
||
### is\_initial\_point\_ignored
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_ignored">
|
||
Returns is initial point ignored
|
||
</Attribute>
|
||
|
||
### is\_initial\_point\_required
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_required">
|
||
Returns is initial point required
|
||
</Attribute>
|
||
|
||
### is\_initial\_point\_supported
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.is_initial_point_supported">
|
||
Returns is initial point supported
|
||
</Attribute>
|
||
|
||
### optimize
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.optimize" signature="optimize(num_vars, objective_function, gradient_function=None, variable_bounds=None, initial_point=None)">
|
||
Perform optimization.
|
||
|
||
**Parameters**
|
||
|
||
* **num\_vars** (*int*) – Number of parameters to be optimized.
|
||
* **objective\_function** (*callable*) – A function that computes the objective function.
|
||
* **gradient\_function** (*callable*) – A function that computes the gradient of the objective function, or None if not available.
|
||
* **variable\_bounds** (*list\[(float, float)]*) – List of variable bounds, given as pairs (lower, upper). None means unbounded.
|
||
* **initial\_point** (*numpy.ndarray\[float]*) – Initial point.
|
||
|
||
**Returns**
|
||
|
||
**point, value, nfev**
|
||
|
||
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
|
||
|
||
**Raises**
|
||
|
||
**ValueError** – invalid input
|
||
</Function>
|
||
|
||
### print\_options
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.print_options" signature="print_options()">
|
||
Print algorithm-specific options.
|
||
</Function>
|
||
|
||
### set\_max\_evals\_grouped
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.set_max_evals_grouped" signature="set_max_evals_grouped(limit)">
|
||
Set max evals grouped
|
||
</Function>
|
||
|
||
### set\_options
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.set_options" signature="set_options(**kwargs)">
|
||
Sets or updates values in the options dictionary.
|
||
|
||
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.
|
||
|
||
**Parameters**
|
||
|
||
**kwargs** (*dict*) – options, given as name=value.
|
||
</Function>
|
||
|
||
### setting
|
||
|
||
<Attribute id="qiskit.aqua.components.optimizers.NELDER_MEAD.setting">
|
||
Return setting
|
||
</Attribute>
|
||
|
||
### wrap\_function
|
||
|
||
<Function id="qiskit.aqua.components.optimizers.NELDER_MEAD.wrap_function" signature="wrap_function(function, args)" modifiers="static">
|
||
Wrap the function to implicitly inject the args at the call of the function.
|
||
|
||
**Parameters**
|
||
|
||
* **function** (*func*) – the target function
|
||
* **args** (*tuple*) – the args to be injected
|
||
|
||
**Returns**
|
||
|
||
wrapper
|
||
|
||
**Return type**
|
||
|
||
function\_wrapper
|
||
</Function>
|
||
</Class>
|
||
|