Matrix addition: 2x2 + 2x3

10142014, 02:41 PM
Post: #1




Matrix addition: 2x2 + 2x3
In CAS, adding two matrices of differing dimensions seem to get zerofilled to equalize dimensions of both(??):
CAS: [[1,2],[3,4]] + [[1,2,3], [4,5,6]] => [[2,4,3],[7,9,6]] Home: [[1,2],[3,4]] + [[1,2,3], [4,5,6]] => Error: Invalid dimension Why? Dale 

10142014, 03:44 PM
Post: #2




RE: Matrix addition: 2x2 + 2x3
The philosophy of the CAS authoer is that you should know better, and that is a helpful shortcut to those that do so (based on my understanding).
TW Although I work for HP, the views and opinions I post here are my own. 

10142014, 04:00 PM
Post: #3




RE: Matrix addition: 2x2 + 2x3
Hmm ... that sounds logical.


10172014, 03:01 AM
Post: #4




RE: Matrix addition: 2x2 + 2x3  
10172014, 06:23 AM
Post: #5




RE: Matrix addition: 2x2 + 2x3
The design philosophy of giac is: the user knows what he does, it's important to provide features to advanced users.
If you have 2 lists of different sizes to add, you can a/ forbid addition b/ add them by adding 0 at the right of the shortest c/ add them by adding 0 at the left of the shortest On the Prime, if you add two matrices with different sizes that are tagged as matrices a/ happens. For example matrix[[1,2],[3,4]]+identity(3) Otherwise and in Xcas, b/ applies if the list are tagged as 1dimensional polynomials (poly1[1,2]+poly1[1,2,3]) because coefficients are written in decreasing order and c/ applies otherwise. 

10172014, 06:37 AM
Post: #6




RE: Matrix addition: 2x2 + 2x3
A shortcut to the consequences of matrix dimensions with respect to addition.


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