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Reference documentation for deal.II version 9.1.0-pre
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#include <deal.II/base/function.h>
Public Member Functions | |
ScalarFunctionFromFunctionObject (const std::function< RangeNumberType(const Point< dim > &)> &function_object) | |
virtual RangeNumberType | value (const Point< dim > &p, const unsigned int component=0) const override |
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Function (const unsigned int n_components=1, const RangeNumberType initial_time=0.0) | |
virtual | ~Function () override=0 |
Function & | operator= (const Function &f) |
virtual void | vector_value (const Point< dim > &p, Vector< RangeNumberType > &values) const |
virtual void | value_list (const std::vector< Point< dim >> &points, std::vector< RangeNumberType > &values, const unsigned int component=0) const |
virtual void | vector_value_list (const std::vector< Point< dim >> &points, std::vector< Vector< RangeNumberType >> &values) const |
virtual void | vector_values (const std::vector< Point< dim >> &points, std::vector< std::vector< RangeNumberType >> &values) const |
virtual Tensor< 1, dim, RangeNumberType > | gradient (const Point< dim > &p, const unsigned int component=0) const |
virtual void | vector_gradient (const Point< dim > &p, std::vector< Tensor< 1, dim, RangeNumberType >> &gradients) const |
virtual void | gradient_list (const std::vector< Point< dim >> &points, std::vector< Tensor< 1, dim, RangeNumberType >> &gradients, const unsigned int component=0) const |
virtual void | vector_gradients (const std::vector< Point< dim >> &points, std::vector< std::vector< Tensor< 1, dim, RangeNumberType >>> &gradients) const |
virtual void | vector_gradient_list (const std::vector< Point< dim >> &points, std::vector< std::vector< Tensor< 1, dim, RangeNumberType >>> &gradients) const |
virtual RangeNumberType | laplacian (const Point< dim > &p, const unsigned int component=0) const |
virtual void | vector_laplacian (const Point< dim > &p, Vector< RangeNumberType > &values) const |
virtual void | laplacian_list (const std::vector< Point< dim >> &points, std::vector< RangeNumberType > &values, const unsigned int component=0) const |
virtual void | vector_laplacian_list (const std::vector< Point< dim >> &points, std::vector< Vector< RangeNumberType >> &values) const |
virtual SymmetricTensor< 2, dim, RangeNumberType > | hessian (const Point< dim > &p, const unsigned int component=0) const |
virtual void | vector_hessian (const Point< dim > &p, std::vector< SymmetricTensor< 2, dim, RangeNumberType >> &values) const |
virtual void | hessian_list (const std::vector< Point< dim >> &points, std::vector< SymmetricTensor< 2, dim, RangeNumberType >> &values, const unsigned int component=0) const |
virtual void | vector_hessian_list (const std::vector< Point< dim >> &points, std::vector< std::vector< SymmetricTensor< 2, dim, RangeNumberType >>> &values) const |
std::size_t | memory_consumption () const |
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FunctionTime (const RangeNumberTypeinitial_time=RangeNumberType(0.0)) | |
virtual | ~FunctionTime ()=default |
RangeNumberType | get_time () const |
virtual void | set_time (const RangeNumberTypenew_time) |
virtual void | advance_time (const RangeNumberTypedelta_t) |
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Subscriptor () | |
Subscriptor (const Subscriptor &) | |
Subscriptor (Subscriptor &&) noexcept | |
virtual | ~Subscriptor () |
Subscriptor & | operator= (const Subscriptor &) |
Subscriptor & | operator= (Subscriptor &&) noexcept |
void | subscribe (const char *identifier=nullptr) const |
void | unsubscribe (const char *identifier=nullptr) const |
unsigned int | n_subscriptions () const |
template<typename StreamType > | |
void | list_subscribers (StreamType &stream) const |
void | list_subscribers () const |
template<class Archive > | |
void | serialize (Archive &ar, const unsigned int version) |
Private Attributes | |
const std::function< RangeNumberType(const Point< dim > &)> | function_object |
Additional Inherited Members | |
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static::ExceptionBase & | ExcInUse (int arg1, std::string arg2, std::string arg3) |
static::ExceptionBase & | ExcNoSubscriber (std::string arg1, std::string arg2) |
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const unsigned int | n_components |
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static const unsigned int | dimension = dim |
This class provides a way to convert a scalar function of the kind
into an object of type Function<dim>. Since the argument returns a scalar, the result is clearly a Function object for which function.n_components == 1
. The class works by storing a pointer to the given function and every time function.value(p,component)
is called, calls foo(p)
and returns the corresponding value. It also makes sure that component
is in fact zero, as needs be for scalar functions.
The class provides an easy way to turn a simple global function into something that has the required Function<dim> interface for operations like VectorTools::interpolate_boundary_values() etc., and thereby allows for simpler experimenting without having to write all the boiler plate code of declaring a class that is derived from Function and implementing the Function::value() function. An example of this is given in the results section of step-53.
The class gains additional expressive power because the argument it takes does not have to be a pointer to an actual function. Rather, it is a function object, i.e., it can also be the result of call to std::bind (or boost::bind) or some other object that can be called with a single argument. For example, if you need a Function object that returns the norm of a point, you could write it like so:
and then pass the my_norm_object
around, or you could write it like so:
Similarly, to generate an object that computes the distance to a point q
, we could do this:
or we could write it like so:
The savings in work to write this are apparent.
Definition at line 702 of file function.h.
ScalarFunctionFromFunctionObject< dim, RangeNumberType >::ScalarFunctionFromFunctionObject | ( | const std::function< RangeNumberType(const Point< dim > &)> & | function_object | ) |
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overridevirtual |
Return the value of the function at the given point. Returns the value the function given to the constructor produces for this point.
Reimplemented from Function< dim, RangeNumberType >.
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private |
The function object which we call when this class's value() or value_list() functions are called.
Definition at line 725 of file function.h.