mirror of
https://github.com/triqs/dft_tools
synced 2024-12-27 23:03:51 +01:00
2c542647fd
- change : all objects are by default stored now by reference, not by copy any more. Unless the trait force_copy_in_expr is true. - rvalue refs are moved into the tree - simplifies a lot the writing of lazy method, objects. - added a macro for methods - tests ok. Further check needed to control absence of copies... - improved documentation
40 lines
1.2 KiB
C++
40 lines
1.2 KiB
C++
#include <triqs/clef.hpp>
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template<typename Domain> struct sum_impl {
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Domain d;
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// C++14
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// double operator() (NotClefExpression const & f) const { double s=0; for (int u=0; u<10; ++u) s += f(u/10.0); return s;}
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// C++11 form
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template <typename F>
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typename std::enable_if< !triqs::clef::is_clef_expression <F>::value, double >::type
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operator() (F const & f) const { double s=0; for (int u=0; u<10; ++u) s += f(u/10.0); return s;}
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TRIQS_CLEF_IMPLEMENT_LAZY_CALL(sum_impl);
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friend std::ostream & operator<<(std::ostream & out, sum_impl const & x) { return out<<"sum";}
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};
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// a little factory ...
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template<typename Domain> sum_impl<Domain> sum_functional (Domain d) {return {d};}
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struct DOM{};
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int main() {
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triqs::clef::placeholder <1> x_; triqs::clef::placeholder <2> y_;
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DOM d;
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// integrate_on_d is the integration functional
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auto integrate_on_d = sum_functional(d);
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// This is a simple application of the sum to a function
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std::cout<< integrate_on_d( x_ >> 2*x_ + 1 ) << std::endl;
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// A function y -> y_ + integrate (x -> 2*x + y)
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auto e1 = y_ + integrate_on_d( x_ >> 2*x_ + y_ );
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std::cout<< e1 << std::endl;
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std::cout<< eval (e1 ,y_ =0) << std::endl;
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}
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