keyword
c[100]_2_1.5_[100]_400.txt
msym	     rotation    radian      seed      
3            3           1           34567
random segments
50000
lattice (average grain size in pixels, < 100)
50

The second line is the keyword for the files.  A file with the
name 'gbcd_f_',keyword must be in this directory and it should be a 
normal gbcd file, as produced by simulate_gbcd.

If Cubic, msym = 3
If Hexagonal, msym = 2
If Tetragonal, msym = 1
If Trigonal, msym = 4

The rotation variable is unused, but should be set to 3 when
the gbcd is calculated from these data.

If Euler angles in degrees, use radian=0
If Euler angles in radians, use radian=1

the fourth number is the seed for the random number generator.
to get different 'random' output, change this number.

The number on the next line is the number of line segments that will be generated.

The output is a file labeled 'segments_',keyword, that can be used as input for
calc_gbcd