40 lines
969 B
Plaintext
40 lines
969 B
Plaintext
# Numerical difference calculation of error in forces
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units metal
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atom_style atomic
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atom_modify map yes
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lattice fcc 5.358000
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region box block 0 3 0 3 0 3
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create_box 1 box
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create_atoms 1 box
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mass 1 39.903
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velocity all create 10 2357 mom yes dist gaussian
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pair_style lj/cubic
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pair_coeff * * 0.0102701 3.42
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neighbor 1.0 bin
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timestep 0.001
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fix numforce all numdiff 100 0.0001
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fix numstress all numdiff/stress 100 0.0001
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fix nve all nve
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variable errx atom fx-f_numforce[1]
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variable erry atom fy-f_numforce[2]
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variable errz atom fz-f_numforce[3]
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dump errors all custom 100 force_error.dump v_errx v_erry v_errz
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variable ferrsq atom (fx-f_numforce[1])^2+(fy-f_numforce[2])^2+(fz-f_numforce[3])^2
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compute faverrsq all reduce ave v_ferrsq
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fix avfaverrsq all ave/time 100 1 100 c_faverrsq ave running
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compute myvirial all pressure NULL virial
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thermo_style custom step temp pe press c_faverrsq f_avfaverrsq c_myvirial[1] f_numstress[1]
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thermo 100
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run 500
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