 Row vector (multiplication by a column vector) - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: Row vector (multiplication by a column vector) (/thread-19497.html) Row vector (multiplication by a column vector) - DrD - 02-01-2023 02:21 PM Example: 3x1 column vector multiplying a 1x3 row vector a:=[[1,2,3]]; b:=[4,5,6]; a*b => "dotvecteur Error: Invalid dimension" However, by converting b to a 1x3 matrix first, works. b:=TRN(TRN(b)); // Converts the 1x3 vector to a 1x3 matrix ... a*b => [[4,5,6],[8,10,12],[12,15,18]] Requiring conversion from a row vector to a 1x3 matrix data type is an extra step that could benefit from software improvement, in cases such as these. RE: Row vector (multiplication by a column vector) - jte - 02-01-2023 09:56 PM When I took my first linear algebra course, I was taught that vectors are simply special cases of matrices (1×n or n×1, rather than m×n). RE: Row vector (multiplication by a column vector) - parisse - 02-02-2023 11:16 AM On the other hand, if you handle this case without error, it will be harder to detect a real error...