RE: operate a matrix of derivations
- To: mathgroup at smc.vnet.net
- Subject: [mg39221] RE: [mg39184] operate a matrix of derivations
- From: F.H.Simons at tue.nl
- Date: Tue, 4 Feb 2003 02:21:54 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
When your first matrix is a matrix of functions, then the dot product
results in a matrix of sums of products of arguments and functions. A simple
substitution then will give you the result you are looking for.
In[1]:=
mat1 = {{D[#1, x] & , 0 & },
{D[#1, y] & , D[#1, x] & }}
Out[1]=
{{D[#1, x] & , 0 & },
{D[#1, y] & , D[#1, x] & }}
In[2]:=
mat2 = {{x*y, x}, {x + y, 3}}
Out[2]=
{{x*y, x}, {x + y, 3}}
In[3]:=
mat1 . mat2 /. a_.*b_Function -> b[a]
Out[3]=
{{y, 1}, {1 + x, 0}}
Fred Simons
Eindhoven University of Technology
> -----Original Message-----
> From: iselig at techunix.technion.ac.il
To: mathgroup at smc.vnet.net
> [mailto:iselig at techunix.technion.ac.il]
> Sent: maandag 3 februari 2003 7:08
> To: mathgroup at smc.vnet.net
> Subject: [mg39221] [mg39184] operate a matrix of derivations
>
>
> I want to make a matrix of derivations, so I will be able to multiply
> it by a matrix of functions and get the result matrix
> simple example:
>
> |d/dx 0 | |xy x| |y 1|
> | |.| |=| |
> |d/dy d/dx| |x+y 3| |x+1 0|
>
> thank you
>