SOURCE

function roundToDecimal(num, decimals) {
  const factor = Math.pow(10, decimals);
  return Math.round(num * factor) / factor;
}

function T(td){
console.log(td);

var sps = [1.5,2.5,3.5,4.5,5.5,6.5,7.5,8.5,9.5];

var r_sp = [];

for(var k = 0; k < sps.length; k++){
  
var sp = sps[k];
  
var t_c1 = [], t_c2 = [];
var s_c1 =0, s_c2 = 0;

var c1,c2;

for(var i = 0; i < td.length; i++){
  if(td[i][0] < sp){
    t_c1.push(td[i][1]);
    s_c1 += td[i][1];
  }else{
    t_c2.push(td[i][1]);
    s_c2 += td[i][1];
  }
}

c1 = roundToDecimal(s_c1 / t_c1.length,2);
c2 = roundToDecimal(s_c2 / t_c2.length,2);

var ms = 0;
for(var i = 0; i < t_c1.length; i++){
	ms += Math.pow(t_c1[i] - c1, 2);
}
for(var i = 0; i < t_c2.length; i++){
	ms += Math.pow(t_c2[i] - c2, 2);
}
//console.log('sp = ', sp, '，c1:', c1, '，c2:', c2, '，ms = ', ms);

ms = roundToDecimal(ms, 2);

r_sp.push([ms,sp,c1,c2]);

}


var min_sp;

for(var k=0;k<r_sp.length;k++){
    if(!min_sp){
        min_sp = r_sp[k];
        continue;
    }

    if(min_sp[0] > r_sp[k][0]){
        min_sp = r_sp[k];
    }
}

console.log(min_sp);

var rs = [];

for(var i = 0; i < td.length; i++){
    if(td[i][0] < min_sp[1]){
        rs[i] = roundToDecimal(td[i][1] - min_sp[2],2);
    }else{
        rs[i] = roundToDecimal(td[i][1] - min_sp[3],2);
    }
}


console.log(rs);

var rl = 0;

for(var i =0;i<rs.length;i++){
    rl += Math.pow(rs[i],2);
}
rl = roundToDecimal(rl,2);

console.log(rl);

return rs;
}



var td = [[1,5.56],[2,5.7],[3,5.91],[4,6.4],[5,6.8],[6,7.05],[7,8.9],[8,8.7],[9,9],[10,9.05]];


var rs = T(td);


console.log('------------------------------------------------------------------------');


var td2 = [];

for(var i=0;i<rs.length;i++){
    td2.push([(i+1), rs[i]]);
}

var rs2 = T(td2);

console.log('------------------------------------------------------------------------');

var td3 = [];

for(var i=0;i<rs2.length;i++){
    td3.push([(i+1), rs2[i]]);
}

var rs3 = T(td3);


console.log('------------------------------------------------------------------------');

var td4 = [];

for(var i=0;i<rs3.length;i++){
    td4.push([(i+1), rs3[i]]);
}

var rs4 = T(td4);


console.log('------------------------------------------------------------------------');

var td5 = [];

for(var i=0;i<rs4.length;i++){
    td5.push([(i+1), rs4[i]]);
}

var rs5 = T(td5);

console.log('------------------------------------------------------------------------');

var td6 = [];

for(var i=0;i<rs5.length;i++){
    td6.push([(i+1), rs5[i]]);
}

var rs6 = T(td6);