# [Pw_forum] Electron-phonon interaction ...

Amit Kumar amit76.india at gmail.com
Sun Dec 17 06:21:20 CET 2006

```      Dear Malgorzata,

It's very nice to recieve your useful suggestions.
I tried all the combinations--->
32 32 4 0 0 0,        32 32 32,
32 32 4 1 1 1 --->>> every possible combinations before posting this
problem on the forum.
But I got the same following error  again and again.

electron-phonon interaction  ...

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
from lint : error #        23
cannot remap grid on k-point list
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

stopping ...

I think the source of the above error is something different.

My guess::::

The dense grid must contain all k  and k+q grid points used in the
e-p calculation.

How do we know the above condition has been satisfied for automatic
generated k and q points with nk1=32, nk2=32, nk3=4 and
nq1=4, nq2=4, nq3=1??????

Here is my q-point grid::::

Calculation of the dynamical matrices for ( 4, 4, 1,) uniform grid of
q-points
(   7q-points):
N       xq(1)       xq(2)       xq(3)
1     0.00000     0.00000     0.00000
2     0.00000     0.28868     0.00000
3     0.00000    -0.57735     0.00000
4     0.25000     0.14434     0.00000
5     0.25000     0.43301     0.00000
6    -0.50000    -0.28868     0.00000
7    -0.50000     0.00000     0.00000

And my k-points grid is here::::

number of k points=  166  gaussian broad. (ryd)=  0.0100     nga
uss =   1
cart. coord. in units 2pi/a_0
k(    1) = (   0.0000000   0.0000000   0.0000000), wk =   0.0
312500
k(    2) = (   0.0000000   0.2886751   0.0000000), wk =   0.0
000000
k(    3) = (   0.0000000   0.1443376   0.0000000), wk =   0.0
104167
k(    4) = (   0.0000000   0.4330127   0.0000000), wk =   0.0
000000

*
*
*  k(  166) = (   0.2500000   0.8660254   0.0000000), wk =   0.0000000

See!!!! 0.28868  and 0.2886751 are not exactly equal.

Is this the possible reason for the error like
"cannot remap grid on k-point list"?????

I'm not sure any other there might be any other.
error  and  give me some clue to get rid of this error.

Thank you again for your very very useful letter.

Regards,
Amit

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