adapt epsilon including when it is specified with 0
adapt epsilon including when it is specified with 0

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