Contains functions to estimate linear and nonlinear impulse responses based on local projections by Jord<U+00E0> (2005) <doi:10.1257/0002828053828518>. To estimate nonlinear impulse responses, the data are separated into two regimes by a a transition function, applied in Auerbach and Gorodnichenko (2012) <doi:10.1257/pol.4.2.1>.