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[DivideByZero]

What is the problem you are having?
I need to increase the speed of this program and I have no idea how....


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)

Turing:

%ByDividedByZero type TComplexNumber :     record         a, b : real     end record setscreen("graphics:320;240") procedure setZ (var z : TComplexNumber, a, b : real)     z.a := a     z.b := b end setZ function addZ (z1, z2 : TComplexNumber) : TComplexNumber     var z3 : TComplexNumber % Stores the answer     z3.a := z1.a + z2.a     z3.b := z1.b + z2.b     result z3 end addZ function squareZ (z1 : TComplexNumber) : TComplexNumber     var z3 : TComplexNumber % Stores the answer     z3.a := (z1.a * z1.a) - (z1.b * z1.b)     z3.b := 2 * z1.a * z1.b     result z3 end squareZ function magnitudeZ (z1 : TComplexNumber) : real     var realZ : real % Stores the answer     realZ := sqrt ((z1.a * z1.a) + (z1.b * z1.b))     result realZ end magnitudeZ var c, z1, z2, z3 : TComplexNumber var realZ : real var counter, x, y : int x := 0 y := 0 c.a := -2 c.b := -1.5 setZ (c, -2, -1.5) loop     z1.a := 0     z1.b := 0        counter := 0        loop            counter := counter + 1                z1 := addZ (squareZ (z1), (c))                exit when (magnitudeZ (z1) > 2) or (counter > 255)            end loop        if counter <= 255 then            drawdot (x, y, counter)            else            drawdot (x, y, black)            end if        x += 1        c.a += 1 / (maxx / 4)        if x > maxx then            x := 0                y += 1              c.b += 1 / (maxy / 4)         c.a := -2            end if     exit when y = maxy end loop put Time.Elapsed

Please specify what version of Turing you are using
Version 4.1

[apomb]

write it in another language

[DivideByZero]

apomb @ Fri Oct 30, 2009 10:12 am wrote:

write it in another language

Has to be turing (its for a class)

[apomb]

well, is the assignment to see how efficient you can make it? because if so, it looks like you have it down, the speed is a language-centric problem; Turing just isnt good at doing things like this. but congratulations on making something like this in turing, it is still impressive, no matter how slow it runs.

[DivideByZero]

Turing:

%ByDividedByZero type TComplexNumber :     record         a, b : real     end record setscreen ("graphics:400;300") %setscreen ("offscreenonly") procedure setZ (var z : TComplexNumber, a, b : real)     z.a := a     z.b := b end setZ function addZ (z1, z2 : TComplexNumber) : TComplexNumber     var z3 : TComplexNumber % Stores the answer     z3.a := z1.a + z2.a     z3.b := z1.b + z2.b     result z3 end addZ function squareZ (z1 : TComplexNumber) : TComplexNumber     var z3 : TComplexNumber % Stores the answer     z3.a := (z1.a * z1.a) - (z1.b * z1.b)     z3.b := 2 * z1.a * z1.b     result z3 end squareZ function magnitudeZ (z1 : TComplexNumber) : real     var realZ : real % Stores the answer     realZ := sqrt ((z1.a * z1.a) + (z1.b * z1.b))     result realZ end magnitudeZ var c, z1, z2, z3 : TComplexNumber var realZ : real var counter, x, y : int x := 0 y := 0 c.a := -2 c.b := -1.5 setZ (c, -2, -1.5) var k : int := 45 loop     z1.a := 0     z1.b := 0     counter := 0     loop         counter := counter + 1         z1 := addZ (squareZ (z1), (c))         exit when (magnitudeZ (z1) > 2) or (counter > 255)     end loop     if counter <= 255 then         if counter > 31 or counter < 72 then             counter := counter + k         end if         if counter > 255 then             counter := k         end if         drawdot (x, y, counter)     else         drawdot (x, y, black)     end if     x += 1     c.a += 1 / (maxx / 4)     if x > maxx then         x := 0         y += 1         c.b += 1 / (maxy / 4)         c.a := -2     end if     exit when y = maxy end loop

Changed some colours to make it look nicer (havent improved speed at all)

[Tony]

I'm pretty sure that

code:

if counter <= 255 then         if counter > 31 or counter < 72 then             counter := counter + k         end if         if counter > 255 then             counter := k         end if         drawdot (x, y, counter)     else         drawdot (x, y, black)     end if

is equivalent to

code:

if counter <= 255 then         drawdot (x, y, counter + k) else         drawdot (x, y, black) end if

You could also set the value of "1 / (maxx / 4) " to a constant, and save yourself 2 divisions per pixel.

But those are minor effects. Your Big-O computation is in

code:

loop         counter := counter + 1         z1 := addZ (squareZ (z1), (c))         exit when (magnitudeZ (z1) > 2) or (counter > 255)     end loop

If you can skip the entire loop and get the counter value directly from the value of c, then you run much faster.

Hint: a pixel next to black (255+) has a high probability of also being black. See if you can reuse any of the results you've already computed.

[DemonWasp]

Tony: They aren't the same. His will increment counter by k if counter > 255, whereas yours will not. This isn't important in this case since he resets it to 0 at the end of the loop and never accesses the incremented value.

[Tony]

DemonWasp: but > 255 is inside the "if counter <= 255" statement, thus it will never be true.

[Zren]

Basic Mathematics

c.b += 1 / (maxy / 4)
c.b += 4 / maxy

You also have a few lines that don't change the variable.

[DemonWasp]

Tony: Sorry, I mis-typed. I meant it will increment counter by k if counter <= 255 (since counter > 31 or counter < 72 is always true). Correct replacement code would be:

code:

if counter <= 255 then     counter := counter + k     drawdot (x, y, counter) else     drawdot (x, y, black) end if

[Tony]

Oh, I see what you mean. You're right; and also about the fact that it's not necessary to keep the new value since it's reset.