function computeRegression_v2()
{
    var theta
    var sum = 0
    for(i=0;i<d1.length;i++)
    {
        sum += (-d1[i][1])/(d1[i][0])
    }
    theta = sum / (-d1.length)

    return [[0,0],[200,200*theta]]
}

function computeRegression_v1()
{
    //alert("a")
    d2 = []
    var sum = 0
    var theta = 2
    var lastSum = null
    var dir = false
    var mov = -1
    while(true)
    {
        sum = 0
        for(i = 0;i<d1.length;i++)
        {
            var tx = theta * d1[i][0]
            var ty = d1[i][1]
            var err = Math.pow((tx-ty),2)
            sum += err
        }
        sum = sum * (1/(2*d1.length))
    //  if(prompt("Theta: "+ theta + " / Sum: "+sum)==null) {  break }
        if(sum == 0 || lastSum==sum) { break }
        if(lastSum==null)
        {
            lastSum = sum
            theta -= 1
            console.log("Reducing theta: "+theta)
        }
        else
        {
            if(sum<lastSum)
            {
                theta += mov
            }
            else
            {
                dir = !dir
                mov *= -0.5
                theta += mov
                console.log("Halving theta: "+theta)
                var diff = Math.abs(Math.abs(lastSum)-Math.abs(sum))
                if(diff<0.1)
                {
                    break;
                }
            }
            lastSum = sum
        }
    }
    return [[0,0],[200,200*theta]]
}