arguments: a1:RingElement a2:RingElement b1:RingElement b2:RingElement m:SparseMutableMatrix r1:int r2:int >> .
Modifies rows 'r1' and 'r2' of matrix 'm' as follows: row r1 is replaced with a1*(row r1)+a2*(row r2), and row r2 is replaced with b1*(row r1)+b2*(row r2). The assignment to rows r1,r2 are performed simultaneously.