2opt working! Conceptualization

-- [[ API file ]] --
height,width,length = 8,15,16
blocks = textutils.unserialize(fs.open("blocks","r").readAll())

function calculateDistance(tNode1,tNode2)
    local y1 = tNode1[2]
    local z1 = tNode1[3]
    local y2 = tNode2[2]
    local z2 = tNode2[3]
    return math.sqrt( (z2-z1)^2 + (y2-y1)^2 )
    --return math.abs( (z2-z1) + (y2-y1) )
end

function twoOptSwap(route, i, k)
    local new_route = {}
    for c = 1,i-1 do
        table.insert(new_route,route[c])
    end
    for c = k,i,-1 do
        table.insert(new_route,route[c])
    end
    for c = k+1,#route do
        table.insert(new_route,route[c])
    end
    return new_route
end

function calculateTotalDistance(route)
    local addString = "0 + "
    for i = 1,#route-1 do
        addString = addString..tostring(calculateDistance(route[i],route[i+1])).." + "
    end
    addString = addString.."0"
    loadstring("total_distance = "..addString)()
    return total_distance
end

function getBlockId(x,y,z)
  return blocks[y + z*width + x*length*width + 1]
end

function display(route,distance)
    local l,h = term.getSize()
    shell.run("clear")

    for i = 1,#route-1 do
        paintutils.drawLine(route[i][2],route[i][3],route[i+1][2],route[i+1][3],colors.lime)
    end
    for i,coord in pairs(route) do
        term.setBackgroundColor(colors.yellow)
        term.setTextColor(colors.magenta)
        term.setCursorPos(coord[2],coord[3])
        term.write(string.char(i+64))
    end
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.setCursorPos(1,h)
    term.write(distance)
end

nodes = {}
local x= 0
for y = 0,width -1 do
    for z = 0,length -1 do
        local id = getBlockId(x,y,z)
        if id and id > 0 then
            table.insert(nodes,{x,y,z})
        end
    end
end

-- [[ Main File ]] --

route = {}
route[1] = {1,28,3}
route[2] = {1,36,13}
route[3] = {1,20,8}
route[4] = {1,8,8}
route[5] = {1,44,5}
route[6] = {1,32,13}
route[7] = {1,20,17}

local existing_route = route
local best_distance = 0

function tsp_algorithm()
    local improve = 0
    while improve < 20 do
        best_distance = calculateTotalDistance(existing_route)
        for i = 1,#route-1 do
            for k = i + 1, #route do
                new_route = twoOptSwap(existing_route, i, k)
                new_distance = calculateTotalDistance(new_route)
                if new_distance < best_distance then
                    improve = 0
                    existing_route = new_route
                    best_distance = calculateTotalDistance(existing_route)
                    display(existing_route,best_distance)
                    sleep(.2)
                end
            end
        end
        improve = improve + 1
    end
    return best_distance, existing_route
end

local best_distance,best_route = tsp_algorithm()

--textutils.pagedPrint(textutils.serialize(best_route))