Merging two pedigrees with Ahnentafel numbering scheme.

ahnentafel_transpose.rb

# You have a 4 generation pedigree that you would like to extend
# to a 7 generation pedigree.
# 
#   8   9   10  11  12  13  14  15
#     4       5       6       7
#         2               3
#                 1
# 
# If you take the person on the 4th generation and pull its pedigree, 
# you can merge the two pedigrees to create a new larger pedigree.
# 
# Let's say you would like to extend from person 12 and merge the new four
# generation pedigree into the original so that you have one large pedigree. 
# The end result you are looking for would be the following pedigree:
# 
#   96  97    98  99  100 101   102  103
#     48        49      50        51
#                 24   25
#   8   9   10  11  12  13  14  15
#     4       5       6       7
#         2               3
#                 1
# 
# Note that you can find 12's father (24), mother (25), paternal grandfather(48),etc.
# The problem is that 12's pedigree will be returned by the system with numbering 
# beginning with 1, so you must transpose the Ahnentafel numbers to stitch them 
# in at 12. The algorith requires the following:
# 
#   8+88   9+88   10+88  11+88  12+88  13+88  14+88  15+88
#     4+44       5+44       6+44       7+44
#         2+22               3+22
#                 1+11
# 
# The transpose method will transpose any position value in the pedigree to the new
# number so that it can be stitched in.
# 
# Example Usage:
# 
# transposing with a new base position of 12:
# 
# transpose 1, 12 #=> 12
# transpose 2, 12 #=> 24
# transpose 3, 12 #=> 25
# transpose 4, 12 #=> 48

def transpose(ahnen_position,new_base)
  merge_num=new_base-1
  level = Math.log2(ahnen_position).floor
  to_add = (2**level)*merge_num
  result = ahnen_position+to_add
  result
end

puts (1..15).to_a.collect{|n|transpose(12,n)}