dcd file format

From: Leandro Martínez (leandromartinez98_at_gmail.com)
Date: Fri Nov 24 2006 - 05:44:06 CST

Hi all,

I had fortran programs to read the dcd file format generated by
version 2.5 of namd.
Now it seems that in version 2.6 there has been a change in the DCD format and
the programs do not seem to be able to read the coordinate files anymore.

Previously I read the dcd files using:

      open(10,file=dcdfile,status='old',form='unformatted')
      read(10) dummyc, nset, (dummyi,i=1,8), dummyr, (dummyi,i=1,9)
      read(10) dummyi, dummyr
       read(10) ntotat
      do i = 1, nframes
         read(10) (x(i,j),j=1,ntotat)
         read(10) (y(i,j),j=1,ntotat)
        read(10) (z(i,j),j=1,ntotat)
     end do

Now it seems that the header is the same, but there is a line
between the coordinates of each frame (with 12 real number in
my simulation, I don't know if that is general):

       do i = 1, nframes
         read(10) (t, i =1, 12)
         read(10) (x(i,j),j=1,ntotat)
         read(10) (y(i,j),j=1,ntotat)
        read(10) (z(i,j),j=1,ntotat)
     end do

What is the information contained in that line? The numbers seem to
zero or another number I couldn't identify the meaning. Was that
change in the DCD file format done for which reason? Not surprisingly
the new dcd file is a somewhat larger.

Thanks,
Leandro.

Ps. I think I sent this mail before and uncomplete by mistake. Sorry.

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