Added setZero() to sparse_extractors. AFAIK not needed on std::vector<int> as initializing them to a length sets all entries to zero.
Added setZero() to sparse_extractors. AFAIK not needed on std::vector<int> as initializing them to a length sets all entries to zero.

stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math