/*!
* @fn sum
*
* @headerfile <seqan/parallel.h>
*
* @brief Returns the sum of all elements in a sequence.
*
* @signature TValue sum(seq[, parallelTag]);
*
* @param[in] seq The sequence to sum up, o ftype <tt>TSequence</tt>.
* @param[in] parallelTag Tag to enable/disable parallelism, one of
* <tt>Serial</tt> and <tt>Parallel</tt>, default is
* <tt>Serial</tt>.
*
* @return TValue The sum of the elements in <tt>seq</tt>, of type
* <tt>Value<TSequence>::Type</tt>.
*
* The sequence alphabet must support the <tt>operator+</tt> and conversion from
* zero.
*
* @see partialSum
*/