VMD-L Mailing List

From: Jim Pfaendtner (jpfaendt_at_hec.utah.edu)
Date: Tue Feb 05 2008 - 11:26:47 CST

Dear VMD-L,

I am trying to calculate several angles for each frame in my
trajectory. I'm using the geometry.tcl script posted on the vmd
website.

This code:

animate read dcd $dcdf beg 0 end $nf waitfor all
animate goto start

  puts [phi 0 PRO 35]
  animate next
  puts [phi 0 PRO 35]
  animate next
  puts [phi 0 PRO 35]
  animate next

works fine. It prints out the phi angle or the first three frames in
the trajectory with no problem. When I put this same code in a loop,
it doesn't work at all:

animate read dcd $dcdf beg 0 end $nf waitfor all
animate goto start

for { set j 0 } { $j < 3} { incr j } {
  puts [phi 0 PRO 35]
  animate next
}

this code just prints out the value from frame 0 three times.

Does anyone have any suggestions as to why this doesn't work? There
are a number of different ways to code this problem, but this way is
convenient. Also, it's really puzzling to me why this simple loop
isn't working right.

Any suggestions are greatly appreciated.

Jim