i = fragment.index(b<,i>)

Get the body fragment ID. b may be a ball, clump, or wall pointer. If i is not provided, the last fragment ID is returned. Otherwise, the fragment ID in catalog i is returned where i ranges from 1 to the total number of catalogs. Use the fragment.catalog function or the fragment list command to obtain the catalog information. The fragment.catalog function can be used to obtain the catalog number closest to a specified time.


i - fragment ID


b - body pointer (i.e., ball, clump, or wall pointer)

i - optional catalog number