Kronecker Product?

02172019, 02:39 PM
Post: #1




Kronecker Product?
How could a Kronecker Product be found with the hp prime?
(This would be like Matlab's kron() command, or Wolfram's KroneckerProduct() command). https://en.wikipedia.org/wiki/Kronecker_product I'm no expert on this subject matter, but have recently encountered a need for this in connection with an energy flow problem. Here is an example of a 4x4 identity matrix, with a 2x2 matrix, resulting in an 8x8 Kronecker product: Example (using wxmaxima here): (%i3) a:ident(4); b:matrix ([1,1],[1,1]); kronecker_product(a,b); (a) matrix( [1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1] ) (b) matrix( [1, 1], [1, 1] ) 0 errors, 0 warnings (%o3) matrix( [1, 1, 0, 0, 0, 0, 0, 0], [1, 1, 0, 0, 0, 0, 0, 0], [0, 0, 1, 1, 0, 0, 0, 0], [0, 0, 1, 1, 0, 0, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 1, 1, 0, 0], [0, 0, 0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 0, 0, 1, 1] ) 

02172019, 03:47 PM
(This post was last modified: 02172019 04:25 PM by informach.)
Post: #2




RE: Kronecker Product?
Hi!, DrD :
You can use, for calculate matrices, with Hadamard, as … Syntax : Hadamard bound of a submatrix or element by element multiplication of 2 matrices. hadamard(Matrix,[Matrix]) Examples: hadamard([[1,2],[3,4]]) returns 5√5 hadamard([[1,2],[3,4]],[[3,4],[5,6]]) returns [[3,8],[15,24]] From … User_Guide_EN_2018_01_12_1.pdf (page 475). Too, you can see, from Namir Shammas http://h20331.www2.hp.com/hpsub/download...ionsv3.pdf 

02172019, 05:48 PM
Post: #3




RE: Kronecker Product?
(02172019 03:47 PM)informach Wrote: Hi!, DrD : The hadamard() command fails. Please note that the matricies in the example I provided are of differing sizes: a(4x4) and b(2x2), and produce an 8x8 Kronecker product. I'm not seeing any inbuilt commands that produce the Kronecker product. It may have to be created as an external command, or function. [attachment=6953] 

02172019, 07:52 PM
(This post was last modified: 02172019 08:01 PM by Didier Lachieze.)
Post: #4




RE: Kronecker Product?
Here is a CAS program to calculate the Kronecker product of two matrices:
Code: #cas 

02172019, 08:06 PM
Post: #5




RE: Kronecker Product?
(02172019 07:52 PM)Didier Lachieze Wrote: Here is a CAS program to calculate the Kronecker product of two matrices: Thank you, kind sir! Excellent, as always. I was a bit surprised not to find this in the suite of similar commands, but I'll add this into my collection! 

02182019, 08:58 AM
Post: #6




RE: Kronecker Product?
Here is a slightly updated version, replacing the Home MOD function by the CAS irem function to be more consistent:
Code: #cas 

02182019, 10:26 AM
Post: #7




RE: Kronecker Product?
Thanks for the update. I was studying your makelist construction, and thinking to myself how nicely crafted, made even better, now, by using only CAS commands.
There is a lot, in just your short program, to be learned about the hp prime, CAS/HOME, and programming; embedded in it. This would make a great example for the user guide, to introduce CAS programming structures, and techniques. Short, efficient, and to the point! Very well done! Dale 

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