June 2018 Update

Task/Knapsack-problem-Bounded/Julia/knapsack-problem-bounded-1.julia

@@ -1,26 +1,27 @@
-using MathProgBase
+using MathProgBase, Cbc
 
-immutable KPDSupply{S<:String, T<:Integer}
-    item::S
+struct KPDSupply{T<:Integer}
+    item::String
     weight::T
     value::T
     quant::T
 end
+Base.show(io::IO, kdps::KPDSupply) = print(io, kdps.quant, " ", kdps.item, " ($(kdps.weight) kg, $(kdps.value) €)")
 
-function solve{S<:String, T<:Integer}(gear::Array{KPDSupply{S,T},1},
-                                      capacity::T)
-    w = map(x->x.weight, gear)
-    v = map(x->x.value, gear)
-    q = map(x->x.quant, gear)
-    sol = mixintprog(-v, w', '<', capacity, :Int, 0, q)
-    sol.status == :Optimal || error("This Problem could not be solved")
-    if all(q .== 1)
-        return gear[sol.sol .== 1.0]
+function solve(gear::Vector{KPDSupply{T}}, capacity::Integer) where T<:Integer
+    w = getfield.(gear, :weight)
+    v = getfield.(gear, :value)
+    q = getfield.(gear, :quant)
+    sol = mixintprog(-v, w', '<', capacity, :Int, 0, q, CbcSolver())
+    sol.status == :Optimal || error("this problem could not be solved")
+
+    if all(q .== 1) # simpler case
+        return gear[sol.sol == 1.0]
     else
-        pack = KPDSupply[]
-        s = int(sol.sol)
+        pack = similar(gear, 0)
+        s = round.(Int, sol.sol)
         for (i, g) in enumerate(gear)
-            s[i] != 0 || continue
+            iszero(s[i]) && continue
             push!(pack, KPDSupply(g.item, g.weight, g.value, s[i]))
         end
         return pack

Task/Knapsack-problem-Bounded/Julia/knapsack-problem-bounded-2.julia

@@ -22,11 +22,6 @@ gear = [KPDSupply("map", 9, 150, 1),
         KPDSupply("book", 30, 10, 2)]
 
 pack = solve(gear, 400)
-
-println("The hiker should pack:")
-for s in pack
-    println("    ", s.quant, " ", s.item)
-end
-println()
-println("Packed Weight:  ", mapreduce(x->x.weight*x.quant, +, pack))
-println("Packed Value:  ", mapreduce(x->x.value*x.quant, +, pack))
+println("The hiker should pack: \n - ", join(pack, "\n - "))
+println("\nPacked weight: ", sum(getfield.(pack, :weight)), " kg")
+println("Packed value: ", sum(getfield.(pack, :value)), " €")

Task/Knapsack-problem-Bounded/R/knapsack-problem-bounded-1.r

@@ -0,0 +1,11 @@
+library(tidyverse)
+library(rvest)
+
+task_html= read_html("http://rosettacode.org/wiki/Knapsack_problem/Bounded")
+task_table= html_nodes(html, "table")[[1]] %>%
+  html_table(table, header= T, trim= T) %>%
+  set_names(c("items", "weight", "value", "pieces")) %>%
+  filter(items != "knapsack") %>%
+  mutate(weight= as.numeric(weight),
+         value= as.numeric(value),
+         pieces= as.numeric(pieces))

Task/Knapsack-problem-Bounded/R/knapsack-problem-bounded-2.r

@@ -0,0 +1,21 @@
+library(rgenoud)
+
+fitness= function(x= rep(1, nrow(task_table))){
+  total_value= sum(task_table$value * x)
+  total_weight= sum(task_table$weight * x)
+  ifelse(total_weight <= 400, total_value, 400-total_weight)
+}
+
+allowed= matrix(c(rep(0, nrow(task_table)), task_table$pieces), ncol = 2)
+set.seed(42)
+evolution= genoud(fn= fitness,
+                  nvars= nrow(allowed),
+                  max= TRUE,
+                  pop.size= 10000,
+                  data.type.int= TRUE,
+                  Domains= allowed)
+
+cat("Value: ", evolution$value, "\n")
+cat("Weight:", sum(task_table$weight * evolution$par), "dag", "\n")
+data.frame(item= task_table$items, pieces= as.integer(solution)) %>%
+  filter(solution> 0)