June 2018 Update

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)