<s>
BigDFT	B-Application
is	O
a	O
free	B-Application
software	I-Application
package	O
for	O
physicists	O
and	O
chemists	O
,	O
distributed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
whose	O
main	O
program	O
allows	O
the	O
total	O
energy	O
,	O
charge	O
density	O
,	O
and	O
electronic	O
structure	O
of	O
systems	O
made	O
of	O
electrons	O
and	O
nuclei	O
(	O
molecules	O
and	O
periodic/crystalline	O
solids	O
)	O
to	O
be	O
calculated	O
within	O
density	O
functional	O
theory	O
(	O
DFT	O
)	O
,	O
using	O
pseudopotentials	O
,	O
and	O
a	O
wavelet	O
basis	O
.	O
</s>
<s>
BigDFT	B-Application
implements	O
density	O
functional	O
theory	O
(	O
DFT	O
)	O
by	O
solving	O
the	O
Kohn	O
–	O
Sham	O
equations	O
describing	O
the	O
electrons	O
in	O
a	O
material	O
,	O
expanded	O
in	O
a	O
Daubechies	O
wavelet	O
basis	O
set	O
and	O
using	O
a	O
self-consistent	O
direct	O
minimization	O
or	O
Davidson	O
diagonalisation	O
methods	O
to	O
determine	O
the	O
energy	O
minimum	O
.	O
</s>
<s>
BigDFT	B-Application
was	O
among	O
the	O
first	O
massively	O
parallel	O
density	O
functional	O
theory	O
codes	O
which	O
benefited	O
from	O
graphics	B-Architecture
processing	I-Architecture
units	I-Architecture
(	O
GPU	B-Architecture
)	O
using	O
CUDA	B-Architecture
and	O
then	O
OpenCL	B-Application
languages	O
.	O
</s>
