d3.interpolateRound = d3_interpolateRound;
function d3_interpolateRound(a, b) {
b -= a; return function(t) { return Math.round(a + b * t); };
}
d3.interpolateRound = d3_interpolateRound;
function d3_interpolateRound(a, b) {
b -= a; return function(t) { return Math.round(a + b * t); };
}