Hello! :) When performing matrix multiplications expressions get expanded like in the following Example. Is there a way to avoid expansion, that is to leave the parenthesis Thanks Javier Ros Example: ----------------- matrix aux1 [[-d331*sin(q3)*dq3-d332*cos(q3)*dq3],[d331*cos(q3)*dq3-d332*sin(q3)*dq3],[0]] matrix R23 [[cos(q3),-sin(q3),0],[sin(q3),cos(q3),0],[0,0,1]] matrix R12.mul(aux1) [[d332*sin(q2)*sin(q3)*dq3-d331*cos(q2)*sin(q3)*dq3-d332*cos(q3)*cos(q2)*dq3-d331*sin(q2)*cos(q3)*dq3],[-d332*cos(q2)*sin(q3)*dq3-d331*sin(q2)*sin(q3)*dq3+d331*cos(q3)*cos(q2)*dq3-d332*sin(q2)*cos(q3)*dq3],[0]] ----------------- What I want is to obtain something like cos(q3)*(-d331*sin(q3)*dq3-d332*cos(q3)*dq3)+.... and so on for the first (0,0) matrix element.