var rows = document.querySelectorAll('tr');
var array = [];
rows.forEach(function (item) {
    var row = [];
    var cols = item.children;
    for (var index in cols) {
        if (cols[index].innerHTML) {
            row.push(parseFloat(cols[index].innerHTML));
        }
    }
    array.push(row);
});

var json = '{"data": ' + document.getElementById('points-input').value + "}";
var points = JSON.parse(json).data;
var x = [];
var y = [];
points.forEach(function (item) {
    x.push(item[0]);
    y.push(item[1]);
});
x.sort();
y.sort();
var gX = [];
var gY = [];
for (var i = 0; i < array.length; i++) {
    var sumX = 0;
    var sumY = 0;
    for (var j = 0; j < points.length; j++) {
        sumX += array[i][j] * x[j];
        sumY += array[i][j] * y[j];
    }
    gX.push(parseFloat(sumX.toFixed(2)));
    gY.push(parseFloat(sumY.toFixed(2)));
}