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Bug #1081

ideal() * RingElem gives error

Added by Anna Maria Bigatti 8 months ago. Updated 4 months ago.

Status:
Closed
Priority:
Normal
Category:
Buggy Maths
Target version:
Start date:
20 Jun 2017
Due date:
% Done:

100%

Estimated time:
1.01 h
Spent time:

Description

ideal() * RingElem

gives error

History

#1 Updated by Anna Maria Bigatti 8 months ago

fixed it: now testing

#2 Updated by Anna Maria Bigatti 8 months ago

  • Status changed from New to Feedback
  • % Done changed from 0 to 90

added tests in anna.cocoa5

#3 Updated by John Abbott 4 months ago

Should we allow ideals to be multiplied by integers or rational numbers?

I := ideal(x);
2*I;  -->  ERR not defd
I*2;  -->  ERR not defd
RingElem(R,2)*I;  --> works
I*RingElem(R,2);  --> works

Also note the difference below:

I*RingElem(R,2); --> loses factor of 2
I*(2*y);         --> keeps factor of 2

Is this behaviour what we want?

#4 Updated by Anna Maria Bigatti 4 months ago

John Abbott wrote:

Should we allow ideals to be multiplied by integers or rational numbers?

I vote "no"

JAA responds OK, let's try without; if later we need it, we can easily add it.

Also note the difference below:
[...]
Is this behaviour what we want?

This is the only case where it matters, and it works:

/**/ ideal(ZZ, [3]);
ideal(3)
/**/ It * RingElem(ZZ,2);;
ideal(6)

I think it's good enough as it is.

#5 Updated by John Abbott 4 months ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

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