>> x = M.rand(3,1) <-------- 3x1 >> x[M.isfinite(x)] matrix([[ 0.36541551, 0.6305087 , 0.66054899]]) <---------- Should this be 3x1? My workaround is awkward: >> x[M.where(M.isfinite(x).A)[0]] matrix([[ 0.36541551], [ 0.6305087 ], [ 0.66054899]])