maia::dg::projection Namespace Reference

Functions
template<MInt nDim>
void	indices (const MInt i, const MInt n, MInt *const ids)
	Calculate the 2D/3D indices for a given scalar id for accessing a field of n^nDim points. More...

Function Documentation

indices()

template<MInt nDim>

void maia::dg::projection::indices ( const MInt  i, const MInt  n, MInt *const  ids  )

inline

Author

Ansgar Niemoeller (ansgar) a.nie.nosp@m.moel.nosp@m.ler@a.nosp@m.ia.r.nosp@m.wth-a.nosp@m.ache.nosp@m.n.de

Date

2016-06-01

Parameters

[in]	i	Scalar index.
[in]	n	Number of points in one dimension.
[out]	ids	Computed indices for all spatial directions.

This function is the inverse of, e.g. computing a (square) matrix entry position in memory as i*n+j. The last dimension always varies the fastest.

Definition at line 364 of file dgcartesiangalerkinprojection.h.

                                                                 {
  const MInt f1 = i / n;
 
  IF_CONSTEXPR(nDim == 2) {
    ids[0] = f1;
    ids[1] = i - f1 * n;
  }
  else {
    const MInt f2 = i / (n * n);
 
    ids[0] = f2;
    ids[1] = f1 - f2 * n;
    ids[2] = i - f1 * n;
  }
}