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			46 lines
		
	
	
		
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			46 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
|  | [/============================================================================ | ||
|  |   Boost.odeint | ||
|  | 
 | ||
|  |   Copyright 2012 Karsten Ahnert | ||
|  |   Copyright 2012 Mario Mulansky | ||
|  |   Copyright 2012 Sylwester Arabas | ||
|  | 
 | ||
|  |   Use, modification and distribution is subject to the Boost Software License, | ||
|  |   Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | ||
|  |   http://www.boost.org/LICENSE_1_0.txt) | ||
|  | =============================================================================/] | ||
|  | 
 | ||
|  | [section Generation functions] | ||
|  | 
 | ||
|  | [import ../examples/generation_functions.cpp] | ||
|  | 
 | ||
|  | In the __tutorial we have learned how we can use the generation functions `make_controlled` and `make_dense_output` to create controlled and dense output stepper from a simple stepper or an error stepper. The syntax of these two functions is very simple: | ||
|  | 
 | ||
|  | [generation_functions_syntax_auto] | ||
|  | 
 | ||
|  | The first two parameters are the absolute and the relative error tolerances and the third parameter is the stepper. Additionally, a second version exists where additionally a maximal step size is supplied which ensures the the step size is not increased above this value. | ||
|  |  In C++03 you can infer the type from the `result_of` mechanism: | ||
|  | 
 | ||
|  | [generation_functions_syntax_result_of] | ||
|  | 
 | ||
|  | To use your own steppers with the `make_controlled` or `make_dense_output` you need to specialize two class templates. Suppose your steppers are called `custom_stepper`, `custom_controller` and `custom_dense_output`. Then, the first class you need to specialize is `boost::numeric::get_controller`, a meta function returning the type of the controller: | ||
|  | 
 | ||
|  | [generation_functions_get_controller] | ||
|  | 
 | ||
|  | The second one is a factory class `boost::numeric::odeint::controller_factory` which constructs the controller from the tolerances and the stepper. In our dummy implementation this class is | ||
|  | 
 | ||
|  | [generation_functions_controller_factory] | ||
|  | 
 | ||
|  | This is all to use the `make_controlled` mechanism. Now you can use your controller via | ||
|  | 
 | ||
|  | [generation_functions_example_custom_controller] | ||
|  | 
 | ||
|  | For the dense_output_stepper everything works similar. Here you have to specialize `boost::numeric::odeint::get_dense_output` and `boost::numeric::odeint::dense_output_factory`. These two classes have the same syntax as their relatives `get_controller` and `controller_factory`. | ||
|  | 
 | ||
|  | All controllers and dense-output steppers in odeint can be used with these mechanisms. In the table below you will find, which steppers is constructed from `make_controlled` or `make_dense_output` if applied on a stepper from odeint: | ||
|  | 
 | ||
|  | [include make_controlled_table.qbk] | ||
|  | [include make_dense_output_table.qbk] | ||
|  | 
 | ||
|  | [endsect] |