support Float32 for alias sampling (#499)

* support Float32 for alias sampling

* update tests

* rm unnecessary sig

* resolve comments

* Update src/sampling.jl

Co-authored-by: David Widmann <[email protected]>

Co-authored-by: David Widmann <[email protected]>

Author: findmyway

src/sampling.jl

@@ -584,7 +584,7 @@ end
 direct_sample!(a::AbstractArray, wv::AbstractWeights, x::AbstractArray) =
     direct_sample!(Random.GLOBAL_RNG, a, wv, x)
 
-function make_alias_table!(w::AbstractVector{Float64}, wsum::Float64,
+function make_alias_table!(w::AbstractVector, wsum,
                            a::AbstractVector{Float64},
                            alias::AbstractVector{Int})
     # Arguments:

test/wsampling.jl

@@ -37,15 +37,23 @@ import StatsBase: direct_sample!, alias_sample!
 n = 10^6
 wv = weights([0.2, 0.8, 0.4, 0.6])
 
-a = direct_sample!(4:7, wv, zeros(Int, n, 3))
-check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
-test_rng_use(direct_sample!, 4:7, wv, zeros(Int, 100))
-
-a = alias_sample!(4:7, wv, zeros(Int, n, 3))
-check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
-
-a = sample(4:7, wv, n; ordered=false)
-check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
+for wv in [
+    weights([0.2, 0.8, 0.4, 0.6]),
+    weights([2, 8, 4, 6]),
+    weights(Float32[0.2, 0.8, 0.4, 0.6]),
+    Weights(Float32[0.2, 0.8, 0.4, 0.6], 2),
+    Weights([2, 8, 4, 6], 20.0),
+]
+    a = direct_sample!(4:7, wv, zeros(Int, n, 3))
+    check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
+    test_rng_use(direct_sample!, 4:7, wv, zeros(Int, 100))
+
+    a = alias_sample!(4:7, wv, zeros(Int, n, 3))
+    check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
+
+    a = sample(4:7, wv, n; ordered=false)
+    check_wsample_wrep(a, (4, 7), wv, 5.0e-3; ordered=false)
+end
 
 for rev in (true, false), T in (Int, Int16, Float64, Float16, BigInt, ComplexF64, Rational{Int})
     r = rev ? reverse(4:7) : (4:7)
@@ -56,7 +64,6 @@ for rev in (true, false), T in (Int, Int16, Float64, Float16, BigInt, ComplexF64
     check_wsample_wrep(aa, (4, 7), wv, -1; ordered=true, rev=rev)
 end
 
-
 #### weighted sampling without replacement
 
 function check_wsample_norep(a::AbstractArray, vrgn, wv::AbstractWeights, ptol::Real;