Improve error message when initial_params / initial_state has wrong length

Author: penelopeysm

Project.toml

@@ -3,7 +3,7 @@ uuid = "80f14c24-f653-4e6a-9b94-39d6b0f70001"
 keywords = ["markov chain monte carlo", "probabilistic programming"]
 license = "MIT"
 desc = "A lightweight interface for common MCMC methods."
-version = "5.6.1"
+version = "5.6.2"
 
 [deps]
 BangBang = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"

src/sample.jl

@@ -653,15 +653,15 @@ tighten_eltype(x::Vector{Any}) = map(identity, x)
 
 @nospecialize check_initial_params(x, n) = throw(
     ArgumentError(
-        "initial parameters must be specified as a vector of length equal to the number of chains or `nothing`",
+        "initial_params must be specified as a vector of length equal to the number of chains or `nothing`",
     ),
 )
 check_initial_params(::Nothing, n) = nothing
 function check_initial_params(x::AbstractArray, n)
     if length(x) != n
         throw(
             ArgumentError(
-                "incorrect number of initial parameters (expected $n, received $(length(x))"
+                "the length of initial_params must be equal to the number of chains ($n; received $(length(x)))"
             ),
         )
     end
@@ -671,15 +671,15 @@ end
 
 @nospecialize check_initial_state(x, n) = throw(
     ArgumentError(
-        "initial states must be specified as a vector of length equal to the number of chains or `nothing`",
+        "initial_state must be specified as a vector of length equal to the number of chains or `nothing`",
     ),
 )
 check_initial_state(::Nothing, n) = nothing
 function check_initial_state(x::AbstractArray, n)
     if length(x) != n
         throw(
             ArgumentError(
-                "incorrect number of initial states (expected $n, received $(length(x))"
+                "the length of initial_state must be equal to the number of chains ($n; received $(length(x)))"
             ),
         )
     end