startup

function calcDeterminant(matrix)
  local determinant = 0
  for i = 1, table.getn(matrix), 1 do
    if table.getn(matrix) > 2 then
      local newMatrix = {}
      local line = 1
      for j = 1, table.getn(matrix), 1 do
        if j ~= i then
          newMatrix[line] = {}
          for k = 2, table.getn(matrix), 1 do
            newMatrix[line][k - 1] = matrix[j][k]
          end
          line = line + 1
        end
      end
      local value = matrix[i][1] * calcDeterminant(newMatrix)
      if i % 2 == 0 then
        value = value * -1
      end
      determinant = determinant + value
    elseif table.getn(matrix) == 2 then
      determinant = matrix[1][1] * matrix[2][2] - matrix[1][2] * matrix[2][1]
    end
  end
  return determinant
end

local modem = peripheral.wrap("top")

modem.open(2)

while(true) do
  local event, side, freq, repFreq, message1, distance = os.pullEvent("modem_message")
  print(message1)
  event, side, freq, repFreq, message2, distance = os.pullEvent("modem_message")
  print(message2)
  event, side, freq, repFreq, message3, distance = os.pullEvent("modem_message")
  print(message3)
  --event, side, freq, repFreq, message4, distance = os.pullEvent("modem_message")
  --print(message4)
  local matrix = {{2 * message1["x"], 2 * message1["y"], 2 * message1["z"]}, {2 * message2["x"], 2 * message2["y"], 2 * message2["z"]}, {2 * message3["x"], 2 * message3["y"], 2 * message3["z"]}}
  local D = calcDeterminant(matrix)
  print(D)
  local DxMatrix = matrix
  DxMatrix[1][1] = message1["dist"] - message1["x"] * message1["x"] - message1["y"] * message1["y"] - message1["z"] * message1["z"]
  modem.transmit(3, 0, "Pong")
  print("Message Sent")
end