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https://github.com/triqs/dft_tools
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64 lines
1.6 KiB
ReStructuredText
64 lines
1.6 KiB
ReStructuredText
.. highlight:: c
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.. _gf_call:
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Operator()
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==================================
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**Synopsis** ::
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value_type const & operator()(mesh_t::domain_t::point_t) const (1)
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view_type operator()() const (2)
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ClefExpression operator()(ClefExpression) const (3)
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The operator () is in charge of evaluating the Green function on its domain,
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by any means (e.g. interpolation) that the specialization define.
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For example, g(t) for a Green function in time would return some interpolation of
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the value of g between the closest mesh point.
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Hence, this operator is only const : it would make no sense to modify g(t).
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(to modify the Green function, cf operator []).
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However, the Clef automatic assignment method (cf...) *is* written
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with the () operator, in order have a better syntax for multivariable function.
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It would be more logical to use [], but a strange, old and extremely inconvenient limitation of C++
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forbids to overload [] for multiple variables...
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NB : This is valid for both the container (e.g. gf), and the view (e.g. gf_view).
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.. _gf_element_access:
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(1) Evaluation
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---------------------------------
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Evaluation at one point of the domain.
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NB : Specialization may provide other overloads.
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.. _gf_making_view:
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(2) Building a view
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---------------------------------
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The special case (2) (no argument) returns a complete view of the object
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(equivalent to view_type(* this)).
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.. _gf_lazy:
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(3) Interaction with clef expressions
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-------------------------------------------------
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* gf and gf_view can be used with the triqs::clef library
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