Script to accompany https://docs.google.com/spreadsheets/d/14-ZOCOVa7PEaG4KpsZojiwTQtC2It4HqFTsqFu2s3z4/edit?usp=sharing. Originally posted on http://theianchan.com/one-data-science-a-day/day-eighteen/.

gradientDescent.gs

var PARAM_M = "J79";
var PARAM_B = "J80";
var PARAM_EPOCH = "E79";
var PARAM_LEARN = "E80";
var RMSE = "M79";

var NEW_M = "J104";
var NEW_B = "M104";

function updateParameters(m, b) {
  var ss = SpreadsheetApp.getActiveSheet();
  ss.getRange(PARAM_M).setValue(m);
  ss.getRange(PARAM_B).setValue(b);
}

function runEpoch() {
  var ss = SpreadsheetApp.getActiveSheet();
  var newM = ss.getRange(NEW_M).getDisplayValue();
  var newB = ss.getRange(NEW_B).getDisplayValue();
  appendTable();
  updateParameters(m=newM, b=newB);
}

function appendTable() {
  var ss = SpreadsheetApp.getActiveSheet();
  var m = ss.getRange(PARAM_M).getDisplayValue();
  var b = ss.getRange(PARAM_B).getDisplayValue();
  var learn = ss.getRange(PARAM_LEARN).getDisplayValue();
  var rmse = ss.getRange(RMSE).getDisplayValue();
  var row = (ss.getLastRow() + 1).toString();
  
  ss.getRange("B" + row + ":E" + row).setValues([[m, b, learn, rmse]]); 
}

function runEpochs() {
  var ss = SpreadsheetApp.getActiveSheet();
  var numEpochs = ss.getRange(PARAM_EPOCH).getDisplayValue();
  
  for (var i = 0; i < numEpochs; i++) {
    runEpoch();
  }
}

function reset() {
  updateParameters(1, 1);
  
  var ss = SpreadsheetApp.getActiveSheet();
  var table = ss.getRange("B109:E" + ss.getLastRow().toString());
  table.clear();
}