diff --git a/src/recursive_bp_factor.jl b/src/recursive_bp_factor.jl
index 3324aa2f..33fbceeb 100644
--- a/src/recursive_bp_factor.jl
+++ b/src/recursive_bp_factor.jl
@@ -22,7 +22,7 @@ prob_xy(wᵢ::RecursiveBPFactor, yₖ, xₖ, xᵢ, dᵢ) = prob_xy(wᵢ, yₖ, x
 "P(yₐᵦ|yₐ,yᵦ,xᵢᵗ)"
 prob_yy(wᵢ::RecursiveBPFactor, y, y1, y2, xᵢ, d1, d2) = prob_yy(wᵢ::RecursiveBPFactor, y, y1, y2, xᵢ)
 prob_yy(wᵢ::RecursiveBPFactor, y, y1, y2, xᵢ) = error("Not implemented")
-prob_y0(wᵢ::RecursiveBPFactor, y, xᵢᵗ) = y == 1
+prob_y0(wᵢ::RecursiveBPFactor, y, xᵢᵗ)::Float64 = y == 1
 
 ##############################################
 #### the next methods are optional
@@ -124,10 +124,10 @@ function compute_prob_ys(wᵢ::Vector{U}, qi::Int, μin::Vector{M2}, ψout, T, s
         B, lz + lz1 + lz2, d1 + d2
     end
 
-    Minit = [[float(prob_y0(wᵢ[t], y, xᵢ)) for _ in 1:1, 
-                _ in 1:1, 
+    Minit = [[prob_y0(wᵢ[t], y, xᵢ) for _ in 1:1,
+                _ in 1:1,
                 y in 1:nstates(wᵢ[t],0),
-                xᵢ in 1:qi] 
+                xᵢ in 1:qi]
             for t=1:T+1]
     init = (M2(Minit), 0.0, 0)
     dest, (full, logzᵢ,)  = cavity(B, op, init)