/src/main/java/org/htmlunit/util/geometry/Line2D.java
yIntercept_ = null ;
yIntercept_ = Double.NaN;
startY_ = y1; endX_ = x2; endY_ = y2; isVertical_ = Math.abs(startX_ - endX_) < epsilon; if (isVertical_) { slope_ = Double.NaN; <extra_id_0> } else { slope_ = (endY_ - startY_) / (endX_ - startX_); yIntercept_ = startY_ - slope_ * startX_; } }