How to return a function result instead of doclist in the Solr collapsing/grouping feature?

[Pablo Ricco]

I have the following solr fields in schema.xml:

   - id (string)
   - name (string)
   - category(string)
   - latitude (double)
   - longitude(double)

Is it possible to make a query that groups by category and returns the
average of latitude and longitude instead of the doclist?

Thanks,
Pablo

Get field value in custom searchcomponent (solr 3.3)

[Pablo Ricco]

What is the best way to get a float field value from docID?
I tried the following code but when it runs throws an exception For input
string: "`??eI" at line float lat = Float.parseFloat(tlat);

schemal.xml:
...

...


component.java:

@Override
public void process(ResponseBuilder rb) throws IOException {
DocSet docs = rb.getResults().docSet;
SolrIndexSearcher searcher = req.getSearcher()
FieldCache.StringIndex slat =
FieldCache.DEFAULT.getStringIndex(searcher.getReader(), "latitude");
DocIterator iter = docs.iterator(); while (iter.hasNext()) {
 int docID = iter.nextDoc(); String tlat = slat.lookup[slat.order[docID]];
if (tlat != null) {
 float lat = Float.parseFloat(tlat); //Exception!
}
}
}

Thanks,
Pablo