What is the reason behind this behavior? Type stability? I had expected this to either yield a two by zero matrix or throw an error. julia> A = zeros( 2, 0 ) 2×0 Matrix{Float64} julia> B = zeros( 0, ) Float64[] julia> A * B 2-element Vector{Float64}: 0.0 0.0

Zero matrices are the conventional outputs of multiplying empty matrices . The column-major Vector with length N is treated as a column vector corresponding to a Nx1 matrix. Multiplying a MxN matrix by a Nx1 matrix is expected to make a Mx1 matrix, and given matrix-vector multiplication, the output i…

Matrix with zero columns multiplied by vector with zero elements yields vector

General Usage

Joris_Pinkse August 11, 2025, 1:26am 4

It isn’t a problem. It’s in fact convenient to me.

Topic		Replies	Views
Vector*matrix in 0.6 General Usage	16	2923	February 2, 2017
Inconsistency between zero(x) and zero(T::Type) for matrices Internals & Design	6	505	April 6, 2022
Mapslices failing on n x 0 matrices General Usage question	2	474	February 22, 2018
Is spzeros(m,n) empty? General Usage	3	1359	July 24, 2019
Function zero() with type"Any" General Usage question	14	5930	March 2, 2020

Matrix with zero columns multiplied by vector with zero elements yields vector

Related topics