anychart.onDocumentReady(function () {
var dataTable = anychart.data.table();
dataTable.addData(get_dji_daily_short_data());
var mapping = dataTable.mapAs({value: 1});
var chart = anychart.stock();
var indicator = dataTable.createComputer(mapping);
indicator.addOutputField('customField', 'uid');
indicator.setContext({period: 2000});
indicator.setCalculationFunction(function(row) {
row.set('customField', row.get('value') + this.period);
var indicatorMapping = dataTable.mapAs({value: 'uid'});
plot.line(indicatorMapping);
plot.getSeries(1).name('Custom indicator');
chart.title('Set calculation function');
chart.container('container');