%COMPOUND Compound 2D relationships.%   XIJ = COMPOUND(XI,XJ) returns the compound relationship of the two%   two dimensional transforms XI and XJ which are arranged head-to-%   tail. All X's are 3x1-vectors, all angles within [0..2pi[.%%   References:%      R. Smith, M. Self, P. Cheeseman, "Estimating Uncertain Spatial%      Relationships in Robotics," in Autonomous Robot Vehicles, I.J. %      Cox and G.T. Wilfong, Eds.: Springer-Verlag, 1990, pp. 167-193.%%   See also ICOMPOUND, J1COMP, J2COMP.%   v.1.0, 16.12.00, Kai Arras, ASL-EPFLfunction vik = compound(vij,vjk);xij = vij(1); yij = vij(2); phiij = vij(3);xjk = vjk(1); yjk = vjk(2); phijk = vjk(3);vik(1,1) = xjk*cos(phiij) - yjk*sin(phiij) + xij;vik(2,1) = xjk*sin(phiij) + yjk*cos(phiij) + yij;phiik    = phiij + phijk;if phiik < 0, vik(3,1) = phiik + 2*pi;elseif phiik >= 2*pi, vik(3,1) = phiik - 2*pi;else vik(3,1) = phiik;end;