This function is not yet fully documented. This is a transcript of the text-formatted help.

bbadd  Add a number of black-box operators.
   BB=bbadd(A1,A2,...) creates a black-box operator
   equivalent to the sum A1+A2+...

   If the matrices are normal matrices they will
   be converted to blackbox operators.

   To add operators already in blackbox form you may
   simply use A1+A2+... instead.