The following produces an error on a post-1.7.2-build: matrix m1 = zeros(1,5) matrix m2 = ones(1,5) mymat = m1 | m2 whereas this version works: matrix m1 = zeros(1,5) matrix m2 = ones(1,5) matrix mymat = m1 | m2 I know the second variant (with explicit matrix declaration) is cleaner, but shouldn't the first one also work? -sven