Mean Squared Error of predicted MSMS to observed MSMS
Present thought: As HMMScore is expensive and findLongestCommonSubstring is both expensive and not ideal for eliminating candidates for HMMScore, I am curious how Mean Squared Error (MSE) of a sequence to the observed MSMS data correlates to HMMScore. If there is strong correlation then it is possible that it is a viable (both robust and low computation cost) selector of sequence candidates.
The cost of MSE is O(M + N) where M and N are the cardinality of the MSMS and sequence respectively.