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dft_tools/doc/reference/c++/clef/function_0.cpp
Olivier Parcollet 3fe400d34c doc : split c++ code from rst
- examples split from the rst file using a python script (split_code).
- Final result for the doc is unchanged.
- examples are compiled and tested with the other tests.
- examples' code have been clang-formatted, with triqs style.
- doc compiles much faster, and with the same options as the rest of the
  test.
- examples are added as tests, so they are run by make test, as simple C
  tests.
- done for the tutorials and the reference.
- autocompile removed (changed into triqs_example directive).
- add triqs_example :
   - make a literal include of the source code.
   - runs the compiled example
   - add, as before, the result to the source code in the doc.
- added the script split_code, used to make the changes automatically,
  maybe for later reuse. (in _tools)
2014-05-31 23:00:16 +02:00

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1.3 KiB
C++

#include <triqs/clef.hpp>
#include <iostream>
using namespace triqs::clef;
int main() {
placeholder<0> x_;
placeholder<1> y_;
{ // with one variable
auto f = make_function(2 * x_ + 1, x_);
std::cout << f(3) << std::endl;
std::function<double(double)> F(f);
}
{ // with two variables
auto f = make_function(2 * x_ + y_ + 1, x_, y_);
std::cout << f(3, 4) << std::endl;
std::function<double(double, double)> F(f);
}
{ // Make a function partially
auto f = make_function(2 * x_ + y_ + 1, x_);
// f is a lazy expression expression with placeholder y_, returning a function...
auto f1 = eval(f, y_ = 1); // f1 is a function x-> 2*x + 2
std::cout << f1(10) << std::endl;
}
{ // Currying a function
// auto f = make_function ( make_function( 2*x_ + y_ + 1, x_), y_);
auto f = y_ >> (x_ >> 2 * x_ + y_ + 1);
// f a function y-> x-> 2x+y+1
// f(y) returns a function x-> 2x+y+1
auto g = f(3);
std::cout << g(10) << std::endl;
}
{ // playing with clef::function and std::function
triqs::clef::function<double(double, double)> f2, g2;
f2(x_, y_) = x_ + y_;
std::cout << f2(2, 3) << std::endl;
std::function<double(double, double)> sf2 = f2;
std::cout << sf2(2, 3) << std::endl;
g2(x_, y_) = x_ - y_ + f2(x_, 2 * y_);
std::function<double(double)> sf = x_ >> 2 * x_ + 1;
std::cout << sf(3) << std::endl;
}
}