Ruby block comment and profile questions - ruby

Question

I have written a Ruby version of Erik Demaine's (MIT) docdist8.py. This is available on github as docdist-v3.rb. I faced two weird kind of situations:
1) In the function inner_product there is a block comment:
Inner product between two vectors, where vectors
are repeated as dictionaries of (word, freq) pairs.
Example : inner_product({"and":3, "of":2, "the":5},
{"and":4, "in":1, "of":1, "this":2}) = 14.0
If I wrap this with =begin and =end there is no problem, but if I wrap it with triple double-quotes """, I get errors as follows:
./docdist-v3.rb:71: syntax error, unexpected tIDENTIFIER, expecting kEND
Example : inner_product({"and":3, "of":2, "the":5},
^
./docdist-v3.rb:71: syntax error, unexpected tIDENTIFIER, expecting kEND
Example : inner_product({"and":3, "of":2, "the":5},
^
./docdist-v3.rb:72: syntax error, unexpected kIN, expecting kEND
... {"and":4, "in":1, "of":1, "this":2}) = 14.0
^
./docdist-v3.rb:72: syntax error, unexpected tIDENTIFIER, expecting kEND
... {"and":4, "in":1, "of":1, "this":2}) = 14.0
^
./docdist-v3.rb:72: syntax error, unexpected tIDENTIFIER, expecting kEND
..."and":4, "in":1, "of":1, "this":2}) = 14.0
^
Are there rules / allowed entries for """ that are different from =begin and =end?
2) When I run my program with the time command it executes in about 0.3 seconds. However, if I put require 'profile' the time it takes becomes very high in comparison - 30 seconds. Hence I don't get the correct output at all. This doesn't seem to be the case with the original Python version, where it takes only a marginal extra time to profile. How do I get the same profile run in Ruby?
Note: The two files I used to run the Ruby program are t2.bobsey.txt and t3.lewis.txt. They are available at http://ocw.mit.edu/ans7870/6/6.006/s08/lecturenotes/dd_data.htm

Answer 1

1) Block comments always have the form:
=begin
Comment
=end
You are actually creating a string that is never used:
"""
Not a comment
"""
# => "\nNot a comment\n"
That's why you get an error when adding another quote and that's why the syntax highlighting renders them as strings.
2) It's slower with profiler but I get identical results:
ruby docdist-v3.rb t2.bobsey.txt t3.lewis.txt
File t2.bobsey.txt:262111 lines,49785 words,3354 distinct words
File t3.lewis.txt:1015474 lines,182355 words,8530 distinct words
The distance between the documents is: 0.574160 (radians)