mirror of
https://github.com/triqs/dft_tools
synced 2024-11-01 11:43:47 +01:00
80 lines
4.7 KiB
ReStructuredText
80 lines
4.7 KiB
ReStructuredText
|
.. highlight:: c
|
||
|
|
|
||
|
|
.. _option_template:
|
||
|
|
|
||
|
|
Options template parameters
|
||
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||
|
|
|
||
|
|
The `Option::options` template can take several parameters that determine various aspects of `array` (resp. `matrix`, `vector`) at **compile time**.
|
||
|
|
These parameters can be given in any order in the `options` template, but only at most only (they all have a default, that can also be changed
|
||
|
|
using macros for maximum flexibility).
|
||
|
|
These options parameters determine :
|
||
|
|
|
||
|
|
* the storage order of indices in memory at **compile time**.
|
||
|
|
|
||
|
|
=============================== ===========================================================================================
|
||
|
|
Template parameter Meaning
|
||
|
|
=============================== ===========================================================================================
|
||
|
|
`Tag::C` `[default]` C-style order
|
||
|
|
`Tag::Fortran` Fortran-style order ( NB the base index is still 0, not 1 !)
|
||
|
|
memory_order<i0,i1,i2,... > The tuple <i0,i1,i2...> of size rank determines the storage order of indices in memory
|
||
|
|
memory_order_p<P> P is a triqs::arrays::Permutations::permutation that determines the storage order in memory
|
||
|
|
P[0] is the fastest index, P[rank - 1] the slowest index
|
||
|
|
=============================== ===========================================================================================
|
||
|
|
|
||
|
|
Example of custom order ::
|
||
|
|
|
||
|
|
custom<Permutation<0,1,2> > // same as index_order_Fortran, the first index is the fastest
|
||
|
|
custom<Permutation<2,1,0> > // same as index_order_C, the last index is the fastest
|
||
|
|
custom<Permutation<1,2,0> > // if indices are (i,j,k) : index j is fastest, then k, then i
|
||
|
|
|
||
|
|
* whether bound check are done while accessing array elements or slicing the arrays.
|
||
|
|
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
Template parameter Meaning
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
`Tag::NoBoundCheck` `[default]` Do no bound check at all. This is the default, for speed !
|
||
|
|
`Tag::BoundCheck` Do bound checks. Boundary errors throw triqs::arrays::key_error exception (See ??)
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
|
||
|
|
The macro `TRIQS_ARRAYS_ENFORCE_BOUNDCHECK` change the default to `Tag::BoundCheck` (for debugging purposes).
|
||
|
|
|
||
|
|
Rational : one may want for some array to activate bound check and catch the exception, while keeping faster unchecked arrays elsewhere.
|
||
|
|
|
||
|
|
* whether arrays are initialized at construction.
|
||
|
|
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
Template parameter Meaning
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
`Tag::no_init` `[default]` No initialization of the array at construction (fastest).
|
||
|
|
`Tag::default_init` Initialize with the default constructor of ValueType
|
||
|
|
`Tag::nan_inf_init` Initialize to nan for floating type and std::limits<ValueType>::infinity() for integer type
|
||
|
|
as in D e.g. mainly for detecting easily lack of initialization errors.
|
||
|
|
=============================== ====================================================================================================
|
||
|
|
|
||
|
|
Note that :
|
||
|
|
|
||
|
|
* The macro `TRIQS_ARRAYS_ENFORCE_INIT_NAN_INF` change the default to `Tag::nan_inf_init`.
|
||
|
|
* The macro `TRIQS_ARRAYS_ENFORCE_INIT_DEFAULT` change the default to `Tag::default_init`.
|
||
|
|
|
||
|
|
* Several simple aliases are defined in the namespace Option for the most current cases :
|
||
|
|
|
||
|
|
=============================== ===============================
|
||
|
|
Option aliases
|
||
|
|
=============================== ===============================
|
||
|
|
Option::C Option::options<`Tag::C`>
|
||
|
|
Option::Default Option::options<`Tag::C`>
|
||
|
|
Option::Fortran Option::options<`Tag::Fortran>`
|
||
|
|
=============================== ===============================
|
||
|
|
|
||
|
|
|
||
|
|
* Examples ::
|
||
|
|
|
||
|
|
array<long, 3, Option::options<Option::memory_order <2,1,0> > > A0 (2,3,4);
|
||
|
|
array<long, 3, Option::options<Option::memory_order <0,1,2> > > A1 (2,3,4);
|
||
|
|
array<long, 3, Option::options<Option::memory_order <1,0,2> > > A2 (2,3,4);
|
||
|
|
array<long, 3, Option::Fortran > A4 (2,3,4);
|
||
|
|
|
||
|
|
|
||
|
|
|