###############################################################
#                                                             #
#  		        - pbc.tcl -                           #
#                                                             #
# Andrea Minoia, March 2010                                   #
#                                                             #
# Tcl script for VMD to set the size of the unit cell for     #
# file formats that does not contain such information, e.g.   #
# XYZ and TINKER arc files.                                   #
#                                                             #
# Once the unit cell has been defined, periodic images can be #
# be displayed.                                               #
#                                                             #
# Contacts: 	http://chembytes.wikidot.com                  #
#		minoiaa@gmail.com                             #
#                                                             #
###############################################################
#pick ID for current molecule
set molid [molinfo top]

#pick the number of frames
set n   [molinfo $molid get numframes]

puts -nonewline "\n Set length for a (angstrom):  "
gets stdin a
puts -nonewline "\n Set length for b (angstrom):  "
gets stdin b
puts -nonewline "\n Set length for c (angstrom):  "
gets stdin c
puts -nonewline "\n Set angle alpha (if monoclinic cell press enter):  "
gets stdin alpha
if { $alpha =="" } {
	set alpha 90.000
	set beta 90.000
	set gamma 90.000
} else {
	puts -nonewline "\n Set angle beta (degrees):  "
	gets stdin beta
	puts -nonewline "\n Set angle gamma (degrees):  "
	gets stdin gamma
}

# Applying to all the frames
    for {set i 0} {$i < $n} {incr i} {
        molinfo $molid set frame $i
        molinfo $molid set a $a
        molinfo $molid set b $b
        molinfo $molid set c $c
        molinfo $molid set alpha $alpha
        molinfo $molid set beta $beta
        molinfo $molid set gamma $gamma
    }
#rewind trajectory
animate goto start