Davidk

ex01.exs

@@ -26,50 +26,60 @@ defmodule Ex01 do
         2 is the program well laid out,  appropriately using indentation,
           blank lines, vertical alignment
   """
-  
+
   def counter(value \\ 0) do
+    receive do
+      {:next, from}->
+        send from, {:next_is, value}
+        counter(value+1)
+    end
+  end
+  def new_counter(value \\ 0) do
+    spawn Ex01, :counter, [value]
   end
 
+  def next_value(pid) do
+    send pid, {:next, self}
+    receive do
+      {:next_is, value} -> value
+    end
+  end
 end
 
+
 ExUnit.start()
 
 defmodule Test do
   use ExUnit.Case
 
+
   # Start by uncommenting this test and getting it to pass
   # This test assumes you have a function `counter` that can be spawned
   # and which handles the `{:next, from}` message
 
-  # test "basic message interface" do
-  #   count = spawn Ex01, :counter, []
-  #   send count, { :next, self }
-  #   receive do
-  #     { :next_is, value } ->
-  #       assert value == 0
-  #   end
-  # 
-  #   send count, { :next, self }
-  #   receive do
-  #     { :next_is, value } ->
-  #       assert value == 1
-  #   end
-  # end
+  test "basic message interface" do
+    count = spawn Ex01, :counter, []
+    send count, { :next, self }
+    receive do
+      { :next_is, value } ->
+        assert value == 0
+    end
+
+    send count, { :next, self }
+    receive do
+      { :next_is, value } ->
+        assert value == 1
+    end
+  end
 
   # then uncomment this one
   # Now we add two new functions to Ex01 that wrap the use of
   # that counter function, making the overall API cleaner
 
-  # test "higher level API interface" do
-  #   count = Ex01.new_counter(5)
-  #   assert  Ex01.next_value(count) == 5
-  #   assert  Ex01.next_value(count) == 6
-  # end
+  test "higher level API interface" do
+    count = Ex01.new_counter(5)
+    assert  Ex01.next_value(count) == 5
+    assert  Ex01.next_value(count) == 6
+  end
 
 end
-
-
-
-
-
-

ex02.exs

@@ -1,6 +1,25 @@
 
 defmodule Ex02 do
 
+  @name __MODULE__
+
+  def new_counter(value \\ 0) do
+    {:ok, counter} = Agent.start_link fn -> value end
+    counter
+  end
+
+  def next_value(counter) do
+    Agent.get_and_update(counter, fn val -> {val, val+1} end)
+  end
+
+
+  def new_global_counter(value \\ 0) do
+    Agent.start_link(fn -> value end, name: @name)
+  end
+
+  def global_next_value do
+    Agent.get_and_update(@name, fn val -> {val, val+1} end)
+  end
 end
 
 ExUnit.start()
@@ -23,7 +42,7 @@ defmodule Test do
         2 is the program well laid out,  appropriately using indentation,
           blank lines, vertical alignment
   """
-  
+
 
   @doc """
   First uncomment this test. Here you will be inserting code
@@ -32,26 +51,26 @@ defmodule Test do
   Replace the placeholders with your code.
   """
 
-  # test "counter using an agent" do
-  #   { :ok, counter } = « your code »
-  # 
-  #   value   = « your code »
-  #   assert value == 0
-  # 
-  #   value   = « your code »
-  #   assert value == 1
-  # end
+  test "counter using an agent" do
+    { :ok, counter } = Agent.start_link fn -> 0 end
+
+    value = Agent.get_and_update(counter, fn val -> {val, val+1} end)
+    assert value == 0
+
+    value = Agent.get_and_update(counter, fn val -> {val, val+1} end)
+    assert value == 1
+  end
 
   @doc """
   Next, uncomment this test, and add code to the Ex02 module at the
   top of this file to make those tests run.
   """
 
-  # test "higher level API interface" do
-  #   count = Ex02.new_counter(5)
-  #   assert  Ex02.next_value(count) == 5
-  #   assert  Ex02.next_value(count) == 6
-  # end
+  test "higher level API interface" do
+    count = Ex02.new_counter(5)
+    assert  Ex02.next_value(count) == 5
+    assert  Ex02.next_value(count) == 6
+  end
 
   @doc """
   Last (for this exercise), we'll create a global counter by adding
@@ -60,16 +79,10 @@ defmodule Test do
   that agent into calls to `global_next_value`?
   """
 
-  # test "global counter" do
-  #   Ex02.new_global_counter
-  #   assert Ex02.global_next_value == 0
-  #   assert Ex02.global_next_value == 1
-  #   assert Ex02.global_next_value == 2
-  # end
+  test "global counter" do
+    Ex02.new_global_counter
+    assert Ex02.global_next_value == 0
+    assert Ex02.global_next_value == 1
+    assert Ex02.global_next_value == 2
+  end
 end
-
-
-
-
-
-

ex03.exs

@@ -44,7 +44,7 @@ defmodule Ex03 do
         5	does it produce the correct results on any valid data
 
       Tested
-      if tests are provided as part of the assignment: 	
+      if tests are provided as part of the assignment:
         5	all pass
 
       Aesthetics
@@ -60,7 +60,12 @@ defmodule Ex03 do
   """
 
   def pmap(collection, process_count, function) do
-    « your code here »
+    chunk_size = div(Enum.count(collection) , process_count)
+    Enum.chunk(collection, chunk_size, chunk_size, [])
+    |> Enum.map(&(Task.async(fn -> Enum.map(&1, fn val -> val+1 end) end)))
+    |> Enum.map(&(Task.await(&1)))
+    |> Enum.concat
+
   end
 
 end
@@ -96,5 +101,5 @@ defmodule TestEx03 do
     assert result2 == result1
     assert time2 < time1 * 0.8
   end
-  
+
 end