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

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.. highlight:: c
Assignment
=========================
The `value classes` and the `view classes` have a quite general assignment operator.
We will illustrate it on the `array` class, it is the same for `matrix` and `vector`.
* **Syntax** : the syntax is the same in both cases::
template<typename RHS> array & operator=(const RHS & X);
template<typename RHS> array_view & operator=(const RHS & X);
* **What can be RHS ?**
RHS can be ... anything that models the :ref:`ImmutableCuboidArray` concept !
e.g. : array, array_view, matrix, matrix_view,
but also formal expression (See , e.g. A+B), or any custom object of your choice.
* **Behaviour**
================= ======================================================================= ======================================================================================
Topic value class : array, matrix, vector view: array_view, matrix_view, vector_view
================= ======================================================================= ======================================================================================
RHS ... - RHS models the concept :ref:`ImmutableCuboidArray`. - RHS models :ref:`ImmutableCuboidArray`
[or less ? : RHS can be evaluated in the domain_type::value_type, no domain needed.].
Effect - array is resized to have a domain X.domain() - View's domain must match X's domain or behaviour is undefined.
- array is filled with the evaluation of X. - array is filled with the evaluation of X.
================= ======================================================================= ======================================================================================
* By evaluation of X, we mean :
- a copy if X is an array.
- computing the value if X is an expression.
Compound operators (+=, -=, * =, /=)
-------------------------------------------------
* **Syntax**
The syntax is natural ::
template<typename RHS> array & operator += (const RHS & X);
template<typename RHS> array & operator -= (const RHS & X);
template<typename RHS> array & operator *= (const Scalar & S);
template<typename RHS> array & operator /= (const Scalar & S);
* **What can be RHS ?**
Same as for = operator.
* **Behaviour**
Similar to for = operator, with obvious changes.