Ezgioz/improve pf

[ezgioz]

Instead of defining a matrix "exo" for shocks (order of shocks/size is important)

# Provide the shocks with dictionary 

exo = Dict(:z => [0.00, 0.01, 0.02, 0.03, 0.04], :xi => [0, 0, 0, 0, 0, 0])

# Not provided shocks will be equal to zero by default
# Vector sizes for each shock can be different
# The order the shocks are defined is irrelevant: pf fuction finds the index for each shock

[albop]

Thank you @ezgioz ! This is a welcome addition. Here are a few comments (1/ is the main one): 1/ you should keep the older method of perfect_foresight which takes argument exo::AbstractMatrix{Float64};. What you need to is define a new method perfect_foresight(..., exo::Dict{Symbol, Array}, .... This new method would construct the exogenous matrix of size T_e and pass it the the existing one. 2/ we don't have to assume that all shocks have the same have same length: exo = Dict(:z => [0.00, 0.01, 0.02, 0.03, 0.04], :xi => [0, 0.1, 0]) should work. The method would construct a matrix with size T_e=5. (unrelated: backticks in markdown to quote simple pieces of code) 3/ you could send an error ifT_e>T`