cellBasisVector x,y,z values

From: Shirley Hui (shirleyhui_at_alumni.uwaterloo.ca)
Date: Thu Jul 08 2004 - 08:46:16 CDT

I was wondering if someone could confirm if my understanding is right.

When setting the cellBasisVector1, cellBasisVector2, cellBasisVector3 for
Periodic Boundary conditions in the NAMD config file:

cellBasisVector1 = x,0,0
cellBasisVector2 = 0,y,0
cellBasisVector3 = 0,0,z

The x,y,z are the minimum OR maximum values obtained by running the command
in VMD:

> set everyone [atomselect top all]
> measure minmax $everyone

Can someone please confirm if this is correct?

The tutorial Statistical Mechanics of Proteins doesn't explicitly indicate
that the x,y,z values should be min or max - infact it doesn't tell you how
to obtain the x,y,z values.

The tutorial infact says:

"Three periodic cell basis vectors are to be specified to give the periodic
cell its shape and size. They are cellBasisVector1 , cellBasisVector2, and
cellBasisVector3 . In this file, each vector is perpendicular to the other
two, as indicated by a single x, y, or z value being specified by each. For
instance, cellBasisVector1 is x = 42, y = 0, z = 0. With each vector
perpendicular, a rectangular 3-D box is formed."

http://www.ks.uiuc.edu/Training/SumSchool/materials/sources/tutorials/02-namd-tutorial/namd-tutorial-html/node9.html#SECTION00025100000000000000

Where they came up with the value for x,y,z is not explicitly indicated.
But if my understanding is correct I believe it should be the min max
values.

Thanks,
shirley

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