explaing calculation in sine graph

[Paul Cowan]

Hi,

If you look at this nicely executed sinewave, there contains the following code that determines some values for the x values on each tick of the animation:

  for (i = 0; i < 44; i++) {

    data.push(i * 10 / 84);

  }

I think 44 is really just the available width but is there any reasoning behind this code:

data.push(i * 10 / 84);

I am confused as to the meaning of this calculation. 

[Tito]

for (i = 0; i < 44; i++) {

    data.push(i * 10 / 84);

  }

The above is a for loop used to populate the array data[] which in javascript is a zero based array. Think of data.push as data.insertdata

i=0 

  data.push(0*10/84) = data[0] = 0

i=1

  data.push(1*10/84) = data[1] = 0.119047619047619

i=2

   data.push(2*10/84) = data[2] = 0.2380952380952381

i=3

  data.push(3*10/84) = data[3] =0.3571428571428571

if you change 44 to 22 you will notice the sinewave length changes

[Paul Cowan]

I know what a javascript array is and I know what push etc. means.

I also stated that I thought it was the available width.

Maybe I was not clear in my question.

I meant why is it pushing (i * 10 / 84).

What does this calculation mean?

Why is it multiplying i by 10 divided by 84.

This seems unusually precise for some reason.

Cheers

Paul Cowan

Cutting-Edge Solutions (Scotland)

blog:      http://thesoftwaresimpleton.com/
website: http://www.cuttingedgesolutionsscotland.com/

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[Tito]

ah sorry Paul.

I think the reason for that division is so that you do not get jagged sinewave

var data = [];

for (i = 0; i < 44; i++) {

    data.push(i * 10 / 10);

  }

  console.log(data); gives you integers whereas 10/84 consistently (mostly) floats which makes for smoother sinewaves

check this out

http://stackoverflow.com/questions/31565901/python-equation-graphs-smooth-but-gives-jagged-output