- Dygraph.stackPoints_(seriesPoints, cumulativeYval, seriesExtremes,
+ axisIdx = this.attributes_.axisForSeries(seriesName);
+ if (cumulativeYval[axisIdx] === undefined) {
+ cumulativeYval[axisIdx] = [];
+ }
+ Dygraph.stackPoints_(seriesPoints, cumulativeYval[axisIdx], seriesExtremes,