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dft_tools/doc/reference/c++/arrays/mapped_fnt.rst
Olivier Parcollet 0f524b26fc work on doc
2013-08-27 13:43:58 +02:00

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.. highlight:: c
.. _Mapped:
Simple functions on arrays
==================================
The following functions are mapped on the array (using :ref:`map`):
`abs real imag pow cos sin tan cosh sinh tanh acos asin atan exp log sqrt floor`
meaning that e.g. if `A` is an array,
real(A) models :ref:`ImmutableCuboidArray`, with the same size and returns the real part of the elements.
In other words, it applies the function term-by-term.
.. note::
These functions do NOT compute a new array in memory, they are lazy.
Example :
.. compileblock::
#include <triqs/arrays.hpp>
using triqs::arrays::matrix; using triqs::clef::placeholder;
int main(){
placeholder<0> i_; placeholder<1> j_;
matrix<double> A(2,2);
A(i_,j_) << i_ - j_ ;
std::cout << "A = "<<A << std::endl;
std::cout << "abs(A)= "<<matrix<double>(abs(A))<< std::endl;
}