libpalindrome provides functions for finding palindromes in strings. Classically, a palindrome is a sequence that reads the same forward and backward. For example, the string MADAMIMADAM is a palindrome. There are variations on the definition of palindrome:

1. Gapped palindromes. These palindromes take the form uvu^T, where u^T is the reverse of u, and v can be any string. For example, AHSATANSEZWXOGVWSXGESNATASHA is a gapped palindrome. u = AHSATANSE, v = ZWXOGVWSXG, and u^T=ESNATASHA.

2. Approximate palindromes. These palindromes are nearly the same forward and backward. More precisely, they are a string such that the Levenshtein distance between the string and its reverse is less than some bound. For example, consider a modification of the string above, MADAMIMALAN. The Levenshtein distance between this string and its reverse is 4, so if we set the distance bound to at least 4, this is an approximate palindrome.

3. Alternative definitions of equality. In some problem domains, we are not interested in strings whose forward and reverse are indentical. For example, when identifying palindromes in a string of DNA, we want a string that is identical to its reverse complement. For example, the string ACCTAGGT is its own reverse complement.