arguments: a1:RingElement a2:RingElement b1:RingElement b2:RingElement m:SparseMutableMatrix c1:int c2:int >> .
Modifies columns 'c1' and 'c2' of matrix 'm' as follows: column r1 is replaced with a1*(column c1)+a2*(column c2), and column c2 is replaced with b1*(column c1)+b2*(column c2). The assignment to columns c1,c2 are performed simultaneously.