Re: An easier functional way to divide each Column of matrix by a

*To*: mathgroup at smc.vnet.net*Subject*: [mg127108] Re: An easier functional way to divide each Column of matrix by a*From*: "Nasser M. Abbasi" <nma at 12000.org>*Date*: Sun, 1 Jul 2012 02:05:04 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jsmg8v$1k2$1@smc.vnet.net>*Reply-to*: nma at 12000.org

On 6/30/2012 4:18 AM, Ray Koopman wrote: > What's "unnatural" is that there is no convenient way > to operate on the columns of a matrix, as opposed to the rows. Yes. Also some functions support an argument which can be used to tell it to do things 'row-wise' vs. 'column-wise' (sorry, I am using Matrix terms here, but for me, this is more natural). For example, if A,B are matrices, and we wanted to join them side-by-side (i.e. column wise): Join[A,B,2] To join them on top of each others (i.e. stack them, row-wise), Join[A,B,1] Another example. Given Matrix A and to find the Total of all the rows (i.e row-wise), then the command is Total[A,{2}] and to find the total of all the columns Total[A,{1}] So, some commands do not require Transpose as they have an option to tell it 'which way' to do things. > Tranposing to make > the columns rows, operating on the rows, and then re-transposing may > seem awkward, but it's fast, especially if mat has many rows. I think Mathematica is definitely biased towards rows. I think the original designers of Mathematica liked rows much more than columns :) --Nasser