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DOS error

Posted: Fri Jul 30, 2010 1:14 pm
by sand7000
When I try to use prtdos 3 I get the following error which I am unable to resolve:

simpson_int : number of points in function must be >=6

Any help would be greatly appreciated. My input file is as follows:

Code: Select all

##############################################################
#graphene # with hydrogen # DOS
##############################################################
chkprim 0

ndtset 1

############################
#Definition of the unit cell
############################
acell    4.7502123375E+00  4.7502123375E+00  4.7253121985E+0

rprim    0.86602540378 -0.5  0.0   # a_2
         0.86602540378  0.5  0.0   # a_1
         0.0            0.0  10.0   # a_3

#############################
#Definition of the atom types
#############################
ntypat 2          # 2 atom type(s)
znucl 1 6         # atomic number(s)
                         
########################
#Definition of the atoms
########################
natom 4           # 4 atom(s)
typat 1 1 2 2     # 2 hydrogen 2 carbon

xred    3.3333333333E-01  3.3333333333E-01 -5.3741655116E-02
          6.6666666667E-01  6.6666666667E-01  5.3741655116E-02
          3.3333333333E-01  3.3333333333E-01 -9.0394936935E-03
          6.6666666667E-01  6.6666666667E-01  9.0394936935E-03


######################################
#Definition of the planewave basis set
######################################
ecut 40.0         # Maximal kinetic energy cut-off, in Hartree

###########################################
#Definition of the k-point grid # First Run
###########################################
kptopt 1          # Option for the automatic generation of k points, taking
                  # into account the symmetry
ngkpt 4 4 4

nshiftk 1         # of the reciprocal space (that form a BCC lattice !),
                      # repeated four times, with different shifts :
shiftk  0 0 0

################################
#Definition of the SCF procedure
################################
nstep 30            # Maximal number of SCF cycles
toldfe 1.0d-8     # Will stop when, twice in a row, the difference
                        # between two consecutive evaluations of total energy
                        # differ by less than toldfe (in Hartree)
diemac 12.0       # Here I follow the prescription for a bulk semiconductor.

###########################
#Density of States Options
###########################
prtdos 3

fband 6

natsph 4
iatsph 1 2 3 4
ratsph 1.583404113

Re: DOS error

Posted: Fri Jul 30, 2010 3:17 pm
by pmanglade
I'm not sure but I guess you used too few kpoints. What do you get using ngkpt 8 8 8 ?

Re: DOS error

Posted: Mon Aug 02, 2010 1:43 pm
by sand7000
Unfortunately I tried 8x8x8 and got the same result. With this k point grid I have 65 k-points so I don't think I have too few. Does anyone have any more ideas?

Re: DOS error

Posted: Mon Aug 23, 2010 12:42 pm
by Gabi
Hello sand7000,

I have the same problem using prtdos 3 (value must be >=6).
Did you get to know the cause of the problem in the meantime?

If yes, could you give me some hint how to solve the problem?

Thanks in advance,

Gabi

Re: DOS error

Posted: Sat Sep 04, 2010 9:48 am
by mverstra
Please try the latest production version. As I remember there was a bug in the radial integration somewhere, but it has been fixed.

k-points are certainly not the problem: from 2x2x2 on is ok for the tetrahedron method and it complains more cleanly.

Matthieu