Re: Multiply 2 matrices where one contains differential operators with one that contains functions of x and y

*To*: mathgroup at smc.vnet.net*Subject*: [mg104452] Re: Multiply 2 matrices where one contains differential operators with one that contains functions of x and y*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Sun, 1 Nov 2009 03:58:02 -0500 (EST)

On 10/31/09 at 1:50 AM, nma at 12000.org (Nasser M. Abbasi) wrote: >Lets say A is a 3 by 2 matrix, which contains differential operators >in some entries and 0 in all other entries, as in >A= { { d/dx , 0 } , {0 , d/dy } , { d/dy , d/dx } } >And I want to multiply the above with say a 2 by 3 matrix whose >entries are functions of x and y as in >B = {{x*y, x^3*y, 3*x + y^2}, {2*x, x^4*y, y^2}} >I'd like to somehow be able to do A.B, but ofcourse here I can't, as >I need to "apply" the operator on each function as the matrix >multiplication is being carried out. >I tried to somehow integrate applying the operators in A into the >matrix multiplication of A by B, but could not find a short >"functional" way. Here is a short functional solution In[2]:= Inner[#1[#2] &, A, B] Out[2]= {{y, 3 x^2 y, 3}, {0, x^4, 2 y}, {x + 2, 4 y x^3 + x^3, 2 y}}