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about computional memory consuming
Date: 2005/04/22 12:57
Name: Brighton Yan

Hi,

with OPENMX I am performing a computation for a silicon nanowire with 96 atoms using a 1.0G pentium machine. My calculation always exit because of the lack of memory.
However, the same system has been successfully calculated by other porgram.
could you tell me an efficient way to perform my calculations.
thanks.

some of the main paramters in my *.dat file are as follows:
------------------------------------------------------------
Species.Number 2
<Definition.of.Atomic.Species
Si Si6.0R-s2p2d1 Si_LDA
H H4.0-s1p1 H_TM
Definition.of.Atomic.Species>

Atoms.Number 96
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
<Atoms.SpeciesAndCoordinates # Unit=Ang.
1 Si -6.71929900 -6.71879300 -2.03625000 2.0 2.0
2 Si -6.71929900 -2.87920300 -2.03625000 2.0 2.0
*
………………………………
89 H -4.79953585 -7.97960280 1.11302744 0.5 0.5
90 H -0.96471111 -7.97638915 1.10479311 0.5 0.5
91 H 2.87515445 -7.97671935 1.10921005 0.5 0.5
92 H 7.99082918 -6.72858741 2.93232688 0.5 0.5
93 H 6.70629800 -7.99382117 1.14427603 0.5 0.5
94 H 7.95571834 -2.87800754 2.99481178 0.5 0.5
95 H 7.95581231 0.96269621 2.99331933 0.5 0.5
96 H 7.95642975 4.78180792 2.99349086 0.5 0.5
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors # unit=Ang.
30.0 0.0 0.0
0.00 30.0 0.0
0.0 0.0 5.43
Atoms.UnitVectors>
scf.EigenvalueSolver band # Recursion|Cluster|Band
scf.Kgrid 1 1 2 # means 4x4x4
scf.XcType LDA # LDA|LSDA-CA|LSDA-PW
orderN.HoppingRanges 5.0 # default=5.0 (Ang)
orderN.NumHoppings 2 # default=2
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Re: about computional memory consuming ( No.1 )
Date: 2005/04/13 10:55
Name: T.Ozaki

Hi,

In the below cases A and B, my trials were successful
on a single Pentium 4 machine with 1 GByte memory.
(icc ver. 5.0.1, SuSe Linux 7.1)

(1) Case A

Required cutoff energy 100 Ryd
Used cutoff energy 122.8 128.8 121.5 Ryd
SiR6.0-s2p2d1
H4.0-s1p1
Maximum memory size:
1.25 Gbyte (measured by "top" command)

(2) Case B

Required cutoff energy 90 Ryd
Used cutoff 94.0 94.0 96.0 Ryd
Si6.0R-s2p2d1
H4.0-s2
Maximum memory size:
1.02 Gbyte (measured by "top" command)

For hydrogen, the use of double valence orbitals (H4.0-s2) would
be effective rather than H4.0-s1p1 to span the occupied space
(In addtion, it reduces the total number of basis functions).

For the cutoff energy (scf.energycutoff), 90 Ryd maybe enough
while the used cutoff energies are a little large (the used cutoff
energies are found in the standard output).

Regards,

T.Ozaki




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