fix factoring (#142)

Author: GiggleLiu

src/models/Factoring.jl

@@ -51,7 +51,7 @@ end
 solution_size(f::Factoring, config) = first(solution_size_multiple(f, [config]))
 energy_mode(::Type{<:Factoring}) = SmallerSizeIsBetter()
 
-pack_bits(bits) = sum(i->isone(bits[i]) ? 2^(i-1) : 0, 1:length(bits))
+pack_bits(bits) = sum(i->isone(bits[i]) ? BigInt(1) << (i-1) : BigInt(0), 1:length(bits); init=BigInt(0))
 
 function read_solution(factoring::Factoring,solution::AbstractVector) #return a tuple of 2 numbers result
     num_m = pack_bits(solution[1:factoring.m])

test/models/Factoring.jl

@@ -7,6 +7,9 @@ end
 @testset "read_solution" begin
     f = Factoring(3, 2, 8)
     @test ProblemReductions.read_solution(f, [0, 0, 1, 0, 1]) == (4, 2)
+    # large number
+    f = Factoring(256, 256, BigInt(4611686018427387847) * BigInt(4611686018427387817))
+    @test ProblemReductions.read_solution(f, ones(Bool, 512)) == ((BigInt(1) << 256) - 1, (BigInt(1) << 256) - 1)
 end
 
 @testset "factoring" begin