[gmx-users] clarification regarding contact map - g_mdmat

[Kavyashree M]

Dear users,
I used g_mdmap to calculate the C-alpha contact map of
the trajectory. the distance cut off of 8.0 Ang was selected
The protein is a dimer of 237 residues. The output of -no was
like this -
#res    ratio  tot      mean  natm  mean/atm
  1     1.000  473   473.000    1   473.000
  2     1.000  473   473.000    1   473.000
  3     1.000  473   473.000    1   473.000
  4     1.000  473   473.000    1   473.000
  5     1.000  473   473.000    1   473.000
  6     1.000  473   473.000    1   473.000
  7     1.000  473   473.000    1   473.000
....
So it mean that on an average each calpha atom contacts all
other C-alpha atom in the whole trajectory at some point of time.

In order to cross check it I collected data only for one time frame.
This was also very similar results. all the residues have a minimum
of atleast 471 contacts.

Some one kindly clarify where I am going wrong.? the command
I used was -
g_mdmat -f .*.xtc -s *.tpr -no *.xvg -mean *.xpm -b 4000 -e 4000 -t 8.0

Is this trucating distance in Angstroms or nanometer?

Thank you
Kavya