3D distance formula in CC

radar=peripheral.wrap("back:red")

function ping()
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
    print(v)
  end
end

while true do
  ping()
  sleep(0.1)
end

dist = math.sqrt(math.pow(x1 - x2, 2) + math.pow(y1 - y2, 2) + math.pow(z1 - z2, 2))

RunasSudo, on 20 January 2013 - 04:22 PM said:

http://en.wikipedia....lidean_distance
Try the Euclidean distance formula.

dist = math.sqrt(math.pow(x1 - x2, 2) + math.pow(y1 - y2, 2) + math.pow(z1 - z2, 2))

I think

RunasSudo, on 20 January 2013 - 04:22 PM said:

http://en.wikipedia....lidean_distance
Try the Euclidean distance formula.

dist = math.sqrt(math.pow(x1 - x2, 2) + math.pow(y1 - y2, 2) + math.pow(z1 - z2, 2))

I think

jewelshisen, on 20 January 2013 - 04:29 PM said:

Thanks. Now to figure out how to get the missile variables out of the table.

radarEntities[i]["x"]
radarEntities[i]["y"]
radarEntities[i]["z"]

TheOriginalBIT, on 20 January 2013 - 04:31 PM said:

Loop the entities with a numeric for loop then to this…

radarEntities[i]["x"]
radarEntities[i]["y"]
radarEntities[i]["z"]

local entities = {}
function ping()
  term.clear()
  term.setCursorPos(1,1)
  entities = {}
  for i,v in pairs(radar.getEntities()) do
	entities[#entities + 1]["x"] = v[1]
	entities[#entities + 1]["z"] = v[2]
	entities[#entities + 1]["y"] = v[3]
  end
end

RunasSudo, on 20 January 2013 - 04:35 PM said:

local entities = {}
function ping()
  term.clear()
  term.setCursorPos(1,1)
  entities = {}
  for i,v in pairs(radar.getEntities()) do
	entities[#entities + 1]["x"] = v[1]
	entities[#entities + 1]["z"] = v[2]
	entities[#entities + 1]["y"] = v[3]
  end
end

EDIT: Woo! Level up!

jewelshisen, on 20 January 2013 - 04:41 PM said:

I'm not trying to make a new table… I'm trying to get info OUT of the table and IN to variables. The getEntities method RETURNS a table that does me no good for plugging into a math formula.

function ping()
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
        local x = v[1]
        local z = v[2]
        local y = v[3]
  end
end

Lyqyd, on 20 January 2013 - 04:44 PM said:

You're going to want it in tables anyhow, if you want to be able to track more than just one missile at a time. What's the opposition to tables?

RunasSudo, on 20 January 2013 - 04:44 PM said:

jewelshisen, on 20 January 2013 - 04:41 PM said:

I'm not trying to make a new table… I'm trying to get info OUT of the table and IN to variables. The getEntities method RETURNS a table that does me no good for plugging into a math formula.

*sigh*. Do you want me to spell it out for you? Alright…

function ping()
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
		local x = v[1]
		local z = v[2]
		local y = v[3]
  end
end

Plug values into distance formula.

jewelshisen, on 20 January 2013 - 04:45 PM said:

Because the ICBM radar doesn't return the location for more than one missile.

jewelshisen, on 20 January 2013 - 04:48 PM said:

I'm not trying to be difficult but I have never used tables and never taken any kind of programming class, be it college or CC University. I'm learning this as I go along.

RunasSudo, on 20 January 2013 - 04:48 PM said:

jewelshisen, on 20 January 2013 - 04:45 PM said:

Because the ICBM radar doesn't return the location for more than one missile.

I'm.. sorry? Forgive me if there is a simple explanation, but why is there a radar.getEntities function if it only returns data for one missile? Seems a bit of an odd implementation?

RunasSudo, on 20 January 2013 - 04:48 PM said:

jewelshisen, on 20 January 2013 - 04:48 PM said:

I'm not trying to be difficult but I have never used tables and never taken any kind of programming class, be it college or CC University. I'm learning this as I go along.

Alright then. We all had to learn something at some point.

function ping()
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
	local entityX = v["x"]
	local entityY = v["y"]
	local entityZ = v["z"]
	print( "Distance: "..-- formula goes here )
  end
end

radar=peripheral.wrap("back:red")
print("Enter X:")
x1=tonumber(read())
print("Enter Y:")
y1=tonumber(read())
print("Enter Z:")
z1=tonumber(read())
function ping(x1,y1,z1)
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
    print(v)
    local entityX=v[1]
    local entityY=v[2]
    local entityZ=v[3]
    dist=math.sqrt(math.pow(x1-entityX,2)+math.pow(y1-entityY,2)+math.pow(z1-entityZ,2))
    print("Distance: "..dist)
  end
end

while true do
  ping()
  sleep(0.1)
end

jewelshisen, on 20 January 2013 - 05:17 PM said:

Ok I have hit an issue… Here is my code:

radar=peripheral.wrap("back:red")
print("Enter X:")
x1=tonumber(read())
print("Enter Y:")
y1=tonumber(read())
print("Enter Z:")
z1=tonumber(read())
function ping(x1,y1,z1)
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
	print(v)
	local entityX=v[1]
	local entityY=v[2]
	local entityZ=v[3]
	dist=math.sqrt(math.pow(x1-entityX,2)+math.pow(y1-entityY,2)+math.pow(z1-entityZ,2))
	print("Distance: "..dist)
  end
end

while true do
  ping()
  sleep(0.1)
end

The problem I have is that at like 13 it tells me 'attempt to index ? <a number value> '

What did I do wrong?

TheOriginalBIT, on 20 January 2013 - 05:19 PM said:

Thats because the x,y,z data isn't stored in index 1 2 and 3… its stored in as a key/value!!!! Read my reply… I don't make it a habit to repeating myself for a 3rd time!

jewelshisen, on 20 January 2013 - 05:24 PM said:

TheOriginalBIT, on 20 January 2013 - 05:19 PM said:

Thats because the x,y,z data isn't stored in index 1 2 and 3… its stored in as a key/value!!!! Read my reply… I don't make it a habit to repeating myself for a 3rd time!

Sorry. Missed the quote marks.

TheOriginalBIT, on 20 January 2013 - 05:25 PM said:

jewelshisen, on 20 January 2013 - 05:24 PM said:

TheOriginalBIT, on 20 January 2013 - 05:19 PM said:

Thats because the x,y,z data isn't stored in index 1 2 and 3… its stored in as a key/value!!!! Read my reply… I don't make it a habit to repeating myself for a 3rd time!

Sorry. Missed the quote marks.

not just quote marks… you had numbers instead of "x" "y" "z"

radar=peripheral.wrap("back:red")
print("Enter X:")
x1=tonumber(read())
print("Enter Y:")
y1=tonumber(read())
print("Enter Z:")
z1=tonumber(read())
function ping(x1,y1,z1)
  term.clear()
  term.setCursorPos(1,1)
  for i,v in pairs(radar.getEntities()) do
    local entityY=v["y"]
    local entityX=v["x"]
    local entityZ=v["z"]
    dist=math.sqrt(math.pow(x1-entityX,2)+math.pow(y1-entityY,2)+math.pow(z1-entityZ,2))
    print("Distance: "..dist)
  end
end

while true do
  ping()
  sleep(0.1)
end

for i2,v2 in pairs(v) do
  print(i2 .. "=" .. v2)
end

RunasSudo, on 20 January 2013 - 05:58 PM said:

Try doing a

for i2,v2 in pairs(v) do
  print(i2 .. "=" .. v2)
end

instead of getting the x/y/z and calculating the distance, just to see what sort of data is in the table.

for i,v in pairs(radar.getEntities()) do
  print(i..","..v)
end

jewelshisen, on 20 January 2013 - 06:03 PM said:

-snip-

print(i)

  for i,v in pairs(radar.getEntities()) do
    print(i) --This
    for i2,v2 in pairs(v) do
      print(i2 .. "=" .. v2)
    end
  end

function ping(x1,y1,z1)
	term.clear()
	term.setCursorPos(1,1)
    local p = radar.getEntities()
    local dist=math.sqrt(math.pow(x1-p.x,2)+math.pow(y1-p.y,2)+math.pow(z1-p.z,2))
	print("Distance: "..dist)
end

ChunLing, on 20 January 2013 - 06:24 PM said:

Yes…I'm not sure what RunasSudo was thinking there (apparently that the values were subtables, though why I can't imagine, perhaps because your posted code makes the same error?).

Perhaps you should change the function to look more like:

function ping(x1,y1,z1)
    term.clear()
    term.setCursorPos(1,1)
    v = radar.getEntities()
    dist=math.sqrt(math.pow(v.x,2)+math.pow(y1-v.y,2)+math.pow(z1-v.z,2))
    print("Distance: "..dist)
end

I don't know if this will work exactly, as I don't have the ICBM mod.

ChunLing, on 20 January 2013 - 06:33 PM said:

Yes, and you can access string indexed values of a table by writing the table name and the string index separated by a ".", as in "v.x". This only works for string indexes, but since that's what we're dealing with I didn't think it would be a problem.

Really, both v and dist should be declared local, and I noticed that I accidentally deleted the x1- from your formula, so the answer will be wrong :o/>/>/>

Very sloppy of me. Let me get those.

ChunLing, on 20 January 2013 - 06:24 PM said:

Yes…I'm not sure what RunasSudo was thinking there (apparently that the values were subtables, though why I can't imagine, perhaps because your posted code makes the same error?).

jewelshisen, on 20 January 2013 - 06:37 PM said:

Any way to make it wait for the getEntities() to not return nil so it stops giving an error?

Edit: Also How can i give it zero values for the v.x and so on as holder values so it won't error out?

local entities = radar.getEntities()
if entities then   --This checks to see if entities is not nil
  --Do loopy thing
  local x = v.x
  local y = v.y
  local z = v.z
  if x and y and z then   --This checks to see if all are not nil
    --Calculate distance
  end
end

jewelshisen, on 20 January 2013 - 06:37 PM said:

Edit: Also How can i give it zero values for the v.x and so on as holder values so it won't error out?

local x = v.x or 0
local y = v.y or 0
local z = v.z or 0

TheOriginalBIT, on 20 January 2013 - 07:52 PM said:

jewelshisen, on 20 January 2013 - 06:37 PM said:

Edit: Also How can i give it zero values for the v.x and so on as holder values so it won't error out?

local x = v.x or 0
local y = v.y or 0
local z = v.z or 0

If any of them are nil they will be set to 0…