UT theoretical chemistry code forum

error is:
Illegal division by zero at /../dymmatrix.pl line 166
line 166 is:
$matrix->[$current_displacement][$this_displacement] /= (sqrt($mass[$k]*$mass[$i]));

as I dont know perl scripting, pls anyone comment on why $mass[] is coming as zero.?
Thanks in advance.

prasad

for testing here i attached OUTCAR and DISPLACECAR

It doesn't look like you have done a dynamical matrix calculation with our vtstcode. If you do this, the dynmatrix.pl can be used to extract the Hessian and determine the modes and frequencies.

Dear Dr.Graeme,
Now, after dynamical matrix calculation by modifying INCAR with
ICHAIN=1(my objective is to generate movies for each normal mode),
NSW=49(16 atoms in unitcell),
POTIM=0.0,
IBRION=3 (keeping remaining tags as it is from relaxation run)
and its a single image calculation,

while I am running dymmatrix.pl (DISPLACECAR generated by dymselsph.pl with POSCAR 1 8 0.001) (OUTCAR from dynamical matrix calculation)
result giving all frequencies as ZEROS and imaginary.

I have tried changing EDIFFG from -1E-05 to -1E-8 and also to -1E-7,
also tried ISYM = 0 while EDIFFG =-1E-5
and in all the trails, the same result:all zero frequencies.

Please suggest to solve this problem.
The attached outcar is of EDIFFG=-1E-8

You do not have our vtstcode linked into your vasp binary.

Since I cannot link vtstcode to vasp binay right now,
as I have nice results of IBRION=5 run (DYNMAT file, OUTCAR ..)
can you please suggest if there is any way to generate normal mode movie files (or to create modes.dat) by using vtst scripts?

We have not linked up to the IBRION=5 scheme. It should not be difficult, but we have not done it.

please correct me in understanding format of "modes.dat"

is tat a eigen vector matrix ?
x11 y11 z11 x12 y12 z12 ... x1natom y1natom z1natom
x21 y21 z21 x22 y22 z22 ... x2natom y2natom z2natom
. . . . . . . . . . . .
. . . . . . . . . . . .
xndof1 yndof1 zndof1 xndof2 yndof2 zndof2 ... xndofnatom yndofnatom zndofnatom

if this is correct, i can manually create this file from the eigenvectors of ibrion=5 outcar.

Yes, that's right. If you write a script to do it, we can add it.