Assume that I have a field called *price* for the documents in Solr and I have that field faceted. I want to get the facets as ranges of values (eg: 0-100, 100-500, 500-1000, etc). How to do it?

I can specify the ranges beforehand, but I also want to know whether it is possible to calculate the ranges (say for 5 values) automatically based on the values in the documents?