Graph-er

[Insectoid]

So, I was bored and made this program that takes functions and graphs them. Replace the equation in the function 'y' with whatever function you want, and play around with the window settings (all the constants at the top) so that your function doesn't look like crap. It could use some tweaking but I'm lazy so you can do that yourself. I may eventually make it draw the table but I'm lazy. I don't recommend really, really small xScale values (anything smaller than 0.001 takes AGES to run) and graphing negatives looks really weird and I can't be bothered to fix it. Have fun!

I could have made it draw while generating the table but what the heck.

Turing:

%Graphing and whatnot %graph settings, adjust these to see the graph better const yMax := 100  %More of a minumum, really. the graph will show AT LEAST this much. const xMax := 700 % Dito const xMin := 0 %x value to start the table at const xScale := 0.001 %X will count by this. Scale of 0.1 will count 0, 0.1, 0.2, ... Big = fast, small = accurate const xOffset := 30 %shifts the graph around. Haven't really bothered const yOffset := 20 var font := Font.New ("Times New Roman:12") type coord :     record         x : real         y : real     end record var table : flexible array xMin .. xMin of coord function y (n : real) : real    % if n = 0 then  %uncomment this if you may have division by 0 and adjust the conditional to your needs        % result 0    %end if     result sind (n)*50+50   %Replace with your formula, n is parameter end y proc setTable     table (xMin).x := xMin     table (xMin).y := y(xMin)     for x : xMin .. round (xMax/xScale)         new table, upper (table) + 1         table (upper (table)).x := x*xScale         table (upper (table)).y := y (x*xScale)     end for end setTable proc drawStuff     % for x: 1..xMax by round (600/(xMax))     % Font.Draw (intstr (round(x*xScale)), round (5*x*xScale)+ xOffset, round (yOffset/2), font, black)     %end for     % for y: 1..yMax by round (     Font.Draw (intstr (xMax), 590, yOffset - 20, font, black)     Font.Draw (intstr (yMax), xOffset - 30, 340, font, black)     Font.Draw ("0", xOffset-20, yOffset-20, font, black)     Draw.Line (20, yOffset, 600, yOffset, black)     Draw.Line (xOffset, 20, xOffset, 350, black)     for n : xMin .. upper (table)-1         Draw.Line (round (table (n).x*(600/xMax) + xOffset), round (table (n).y*(350/yMax) + yOffset), round (table(n+1).x*(600/xMax) + xOffset), round (table(n+1).y*(350/yMax)+yOffset), black)     end for end drawStuff setTable drawStuff

[Cezna]

Very cool, but I didn't really understand how to use it...
I was looking for the one line I would have to change and put my formula in, but didn't find it.

Anyway, this looks great (you should post it in that topic with that guy looking for a good graphing calculator for university, since I think you already posted there)

lol

[Insectoid]

replace everything after 'result' in

code:

result sind  (n)*50+50

with your equation. If you get a 'division by 0' error, just uncomment the 3 lines above and change the 'if n = 0' to whatever value is causing the fault.

This doesn't have even close to the functionality that you need for university. Those calculators can derive functions and calculate all sorts of things that I wouldn't have the first clue how to do in code. All this does is graph simple functions.

[andrew.]

That's pretty cool. It made me feel like making one of my own. I hope you don't mind that I took the structure of your code.

Turing:

var xMax : int := 500 var yMax : int := 400 var yScl : int := 50 var xScl : int := 1 var font : int := Font.New ("Arial:10") setscreen("graphics:"+intstr(xMax)+","+intstr(yMax)+",offscreenonly") fcn calculate(n : int) : real     var x : real := 1/xScl*n     result yScl*(sind(x)) %function end calculate proc draw()     drawline(0, yMax div 2, xMax, yMax div 2, black)     drawline(xMax div 2, 0, xMax div 2, yMax, black)     Font.Draw("0", xMax div 2 - 10, yMax div 2 - 15, font, black)     for i : -xMax div 2..xMax div 2         drawline(i + xMax div 2, round(calculate(i)) + yMax div 2, i + 1 + xMax div 2, round(calculate(i + 1)) + yMax div 2, black)         View.Update     end for end draw draw

[Insectoid]

Yeah, that works a lot faster. I'm working right now on making it show the x and y of the list at the mouse X, but it's a lot harder than I thought due to scaling (if the mouse X is at 70, due to scaling the actual position in the graph might be 500).

[Insectoid]

So, yeah, I got the mouse bit semi-working. X is always xx.029 with the current scale (0.001) but w/e.

Just add

Turing:

var mx, my, mb : int loop     Mouse.Where (mx, my, mb)     if mx > xMin and mx < xMax then         Draw.FillBox (10, maxy-25, maxx, maxy, white)          Font.Draw ("Value: " + realstr (table(round (mx/xScale)+xOffset).x, 5) + ", " + realstr (table (round (mx/xScale)+xOffset).y,5), 15, maxy - 20, font, black)     end if end loop

to the bottom of the file.

[andrew.]

Okay, so I was bored (again) and I decided to try to expand it a bit. This one uses Newton's method to approximate roots, and can find numerical derivatives by using first principles and two close points.

Turing:

var xMax : int := 500 var yMax : int := 400 var yScl : real := 0.5 var xScl : real := 5 var font : int := Font.New ("Arial:10") fcn func (x : real) : real     result x**2 - 4 end func fcn diff (x : real) : real     if x = 0 then         result (func (x + (0.0000001 * (1 / (10 ** 7)))) - func (x)) / (0.0000001 * (1 / (10 ** 7)))     else         result (func (x + (x * (1 / (10 ** 7)))) - func (x)) / (x * (1 / (10 ** 7)))     end if end diff fcn root (initial : real) : real     % Uses Newton's Method     var n : real := initial     for i : 1 .. 10         if diff (n) = 0 then             n := n - (func (n)) / (1 / (10 ** 9))         else             n := n - (func (n)) / (diff (n))         end if     end for     result n end root fcn calculate (n : int) : real     var x : real := 1 / xScl * n     result yScl*func(x) end calculate proc plot ()     var window : int := Window.Open("graphics:" + intstr (xMax) + "," + intstr (yMax) + ",offscreenonly")     drawline (0, yMax div 2, xMax, yMax div 2, black)     drawline (xMax div 2, 0, xMax div 2, yMax, black)     Font.Draw ("0", xMax div 2 - 10, yMax div 2 - 15, font, black)     for i : -xMax div 2 .. xMax div 2         drawline (i + xMax div 2, round (calculate (i)) + yMax div 2, i + 1 + xMax div 2, round (calculate (i + 1)) + yMax div 2, black)         View.Update     end for end plot put "f(x) = x\^2 - 4" put "One root is: ", root (1) put "The derivative at x = 5 is: ", diff (5) plot

[Insectoid]

Quit stealing my thunder! It's mine! My own! My precious...

[andrew.]

Haha, sorry Insectoid. I was really bored. I'll stop now.