Hi,

About the Cholesky bug: I've fallen its victim, too, running parallel SIESTA
compiled with ifort 9. However, in my case everything would work when I
turned off the parallelization over k-points. I don't get this error on an
IBM machine with the XL compilers, so the bug seems related to the Intel
compiler. I've tried both MKL and the usual BLAS/LAPACK, it seems the
libraries are not guilty of this. I also tried different levels of
optimization (including zero) for cdiag.f, didn't help either. So it would
be extremely nice if someone from the developers side could take a look and
tell us how to compile SIESTA on parallel Intel clusters with ifort so that
everything works properly.

2007/5/10, Marcos Verissimo Alves <[EMAIL PROTECTED]>:

Hi Mousumi,

> 1. Presently I'm doing some spin-plarized relaxation calculations using
> only the option "SpinPolarized yes". But, I will like to do the
> calculations with fixed spins on each atom. How to fix spins in SIESTA
and
> run relax/scf calculations?

Check the flags FixSpin, TotalSpin and DM.InitSpin, in the siesta manual.
I guess they will do what you want.

>
> 2. I need to calculate magnetic moment and spin-dependent electronic DOS
> of my system of study after fixing the spins properly. Could someone
guide
> as to how we calculate magnetic moment in SIESTA. An input file and,
> output file will be very helpful.

Either I haven't understood what you want, or I am very wrong; but if you
fix the spins on the atoms, you have already determined the magnetic
moment beforehand, haven't you? The magnetic moment is given at the end of
your calculation by Qup-Qdown.

With regards to the spin-dependent DOS, you can calculate it in two ways.
One of them is using the eig2dos.f program, in the Util directory of
siesta. It will calculate the DOS from the eigenvalues, contained in the
EIG file. Another one, more expensive, but good if you want to see the
constributions of different orbitals and even from individual atoms, is to
calculate the Projected Density of States (check for the flag
ProjectedDensityOfStates in the manual). It will calculate the PDOS
**and** DOS.

Since we are speaking of noncollinear spin calculations, I would like to
call the developers' attention to a bug in the noncollinear spin
calculations. I was doing some tests for noncollinear spin calculations,
and I ran into two bugs. One happens in parallel runs, the other in serial
runs.

Before anything, my compilations:

1) Parallel: compiler: ifort 9, mpich - myrinet version at CINECA and also
my own compiled latest version in a dual-core turion -, mpi scalapack and
blacs compiled from scratch. Also the latest version of scalapack, 1.8,
which I compiled and tested a few minutes ago at CINECA. Intel serial mkl
libraries - CINECA doesn't seem to have the cluster version of the mkl.

2) Serial: ifort 9 and mkl. Both versions of siesta are compiled with
-DWXML_INIT_FIX flag.

The bug in parallel runs is one that has come up so many times in the
list, the "error in Cholesky factorization", in cdiag.f . It happens for
the prosaic molecule O2, but also happens for the (also prosaic) ptn with
2 atoms in the unit cell. I have not tried running it for a larger system.

The Cholesky error disappears when I run the calculations with a fully
serial version of siesta, compiled without mpi, scalapack and so on.
However, it crashes when, at the end of the first SCF step, it tries to
write the data to the xml file. It says that a certain unit is already
open, and stops there. I'll be glad to provide all pseudo, fdf and
makefiles, plus the procedures I used to compile each of the versions, if
this is necessary to reproduce the mistake.

Cheers,

Marcos


--
Dr. Marcos Verissimo Alves
Post-Doctoral Fellow
Condensed Matter and Statistical Physics Sector
International Centre for Theoretical Physics
Trieste, Italy

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