Design #1493
Automatic ring mapping in assignment?
Description
We have partly implemented automatic conversion of ring elements (e.g. in multiplication).
Should it also work for assignment? Here is a specific example:
M := mat([[1,x],[0,1]]); // matrix over R M[1,1] := LC(x); // RHS is in CoeffRing(R) -- currently gives MixedRings ERROR
Related issues
History
#1
Updated by John Abbott over 3 years ago
Updated by - Related to Feature #7: Automatic mapping between (some) rings added
#2
Updated by John Abbott over 3 years ago
- Description updated (diff)
My "gut feeling" is that it should work... I expect it to work (perhaps because the destination ring is well defined?)
Is there a situation where one could get unexpected behaviour?
#3
Updated by Anna Maria Bigatti over 3 years ago
Updated by John Abbott wrote:
My "gut feeling" is that it should work... I expect it to work (perhaps because the destination ring is well defined?)
I agree
Is there a situation where one could get unexpected behaviour?
I cannot think of an unexpected behaviour, but just a remark:
In CoCoALib (not in CoCoA5) the assignment to a RINGELEM changes the RING accordingly to the rhs. Here it looks like it goes with the lhs.
HOWEVER, in CoCoALib the function for M[1,1] := .. is SetEntry(M,1,1,..) and not an assignment.
So both CoCoA5 and CoCoALib are self-consistent.
#4
Updated by John Abbott over 3 years ago
- Status changed from New to Resolved
- Assignee set to John Abbott
- % Done changed from 0 to 70
I have changed the impl of mySetEntry so that it tries to auto map the ring elem. Some ad hoc tests pass.
I have also changed the CoCoA-5 ctor for a matrix so that it tries to map all elems of the list of lists (list of rows) into the ring with largest RingID. Again an ad hoc test passed.
Not yet checked in.
Do we need to change doc for this?
#5
Updated by John Abbott over 3 years ago
- Status changed from Resolved to Feedback
- % Done changed from 70 to 90
I have revised the manual entry for matrix. I did note that in the examples mat is used rather than matrix -- is this right?
#6
Updated by Anna Maria Bigatti about 3 years ago
- Status changed from Feedback to Closed
- % Done changed from 90 to 100
John Abbott wrote:
I have revised the manual entry for
matrix. I did note that in the examplesmatis used rather thanmatrix-- is this right?
I admit, I always write mat and I like it.
This assignment works fine on my computer and I close this issue.
#7
Updated by Anna Maria Bigatti 2 months ago
- Related to Feature #645: Automatic mapping of RingElem: user selectable at run-time (GlobalManager?) added