diff --git a/doc/user/dft.tex b/doc/user/dft.tex index a03d816959..ad40c8e590 100644 --- a/doc/user/dft.tex +++ b/doc/user/dft.tex @@ -694,22 +694,23 @@ to generate the desired energy accuracy (with utter disregard for speed). {\bf Important note to users.} We clearly understand that the default (Euler-MacLaurin/Gauss-Legendre) grids are large and result in slow construction of the numerical components of the Kohn-Sham equations. -Alternatively, we have provided access to two-dimensional Lebedev angular -quadratures which can be used in many -cases to substantially reduce the number of grid points per atom while -keeping good accuracy. We have not yet had the opportunity to benchmark -the Lebedev angular quadratures to the same extent that we have for -the Gauss-Legendre. We therefore do not have recommended Lebedev -quadratures for specific target accuracy for all elements of the -periodic table. If the user wants to significantly decrease CPU time -to solution it is suggested that a few prototype benchmark -calculations be done using various Lebedev quadratures (which we describe -below) while -monitoring the numerically integrated density and total energies for -the molecular systems of interest. For many examples we have observed -speed-ups of two or more for the same numerical -accuracy when using Lebedev rather than the default Gauss-Legendre -quadrature. +Alternatively, we have provided access to two-dimensional Lebedev +angular quadratures which can be used in many cases to substantially +reduce the number of grid points per atom while keeping good accuracy. +We have not yet had the opportunity to benchmark the Lebedev angular +quadratures to the same extent that we have for the Gauss-Legendre. +We therefore do not have default Lebedev quadratures for specific +target accuracy for all elements of the periodic table. If the user +wants to significantly decrease CPU time to solution it is suggested +that a few prototype benchmark calculations be done using various +Lebedev quadratures (which we describe below) while monitoring the +numerically integrated density and total energies for the molecular +systems of interest. For many examples we have observed speed-ups of +two or more for the same numerical accuracy when using Lebedev rather +than the default Gauss-Legendre quadrature. In addition, we have +observed that with Lebedev angular quadratures a reduction in the +number of radial shells (perhaps by as much as 30\%) might be possible +while continuing to provide the same level of accuracy. \begin{table}[h]