#28921 closed enhancement (fixed)
Mixed Forms  Zero Treatment for Scalar Multiplication
Reported by:  ghDeRhamSource  Owned by:  

Priority:  major  Milestone:  sage9.1 
Component:  geometry  Keywords:  mixedforms, manifolds 
Cc:  tscrim, egourgoulhon  Merged in:  
Authors:  Michael Jung  Reviewers:  Travis Scrimshaw 
Report Upstream:  N/A  Work issues:  
Branch:  3226bc5 (Commits, GitHub, GitLab)  Commit:  
Dependencies:  Stopgaps: 
Description (last modified by )
Now we have:
sage: M = Manifold(2, 'M') sage: X.<x,y> = M.chart() sage: A = M.mixed_form([1,0,0], name='A') sage: 0*A Mixed differential form 0/\A on the 2dimensional differentiable manifold M
Better is:
sage: M = Manifold(2, 'M') sage: X.<x,y> = M.chart() sage: A = M.mixed_form([1,0,0], name='A') sage: 0*A Mixed differential form zero on the 2dimensional differentiable manifold M sage: (0*A) is M.mixed_form_algebra().zero() True sage: 1*A is A True
Change History (16)
comment:1 Changed 19 months ago by
 Branch set to u/ghDeRhamSource/mixed_forms___zero_treatment_for_scalar_multiplication
comment:2 Changed 19 months ago by
 Cc tscrim egourgoulhon added
 Commit set to 87425aa9ca3a0fddbce658ee9caba85d9650d2c9
 Component changed from PLEASE CHANGE to linear programming
 Description modified (diff)
 Keywords mixedforms manifolds added
 Status changed from new to needs_review
 Type changed from PLEASE CHANGE to enhancement
comment:3 Changed 19 months ago by
 Description modified (diff)
comment:4 Changed 19 months ago by
 Component changed from linear programming to geometry
comment:5 followup: ↓ 6 Changed 19 months ago by
 Milestone changed from sage9.0 to sage9.1
 Reviewers set to Travis Scrimshaw
 Status changed from needs_review to needs_info
Is the is_one
check always quick? Otherwise we shouldn't do it (or implement a faster test).
comment:6 in reply to: ↑ 5 Changed 19 months ago by
Replying to tscrim:
Is the
is_one
check always quick? Otherwise we shouldn't do it (or implement a faster test).
For scalar fields is_one
is slow, because it amounts to comparing a symbolic expression to 1. For comparing to 1, we don't have the equivalent of the fast method is_trivial_zero
.
comment:7 Changed 19 months ago by
 Commit changed from 87425aa9ca3a0fddbce658ee9caba85d9650d2c9 to 3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16
comment:8 Changed 19 months ago by
The base ring is supposed to be the symbolic ring. Anyway, I've changed the check of 1
to a trivial and hence faster one.
comment:9 Changed 19 months ago by
 Status changed from needs_info to needs_review
comment:10 Changed 19 months ago by
 Status changed from needs_review to positive_review
This should be a much faster check. LGTM.
comment:11 Changed 19 months ago by
 Branch changed from u/ghDeRhamSource/mixed_forms___zero_treatment_for_scalar_multiplication to 3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16
 Resolution set to fixed
 Status changed from positive_review to closed
comment:12 Changed 19 months ago by
 Branch changed from 3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16 to u/ghDeRhamSource/3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16
comment:13 Changed 19 months ago by
 Commit changed from 3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16 to 761012b122166a5e7b00a05d36dfdf071fd6ecb8
New commits:
761012b  Trac #28921: Merge branch 'develop' into t/28921/mixed_forms___zero_treatment_for_scalar_multiplication

comment:14 Changed 19 months ago by
New commits:
761012b  Trac #28921: Merge branch 'develop' into t/28921/mixed_forms___zero_treatment_for_scalar_multiplication

comment:15 Changed 19 months ago by
Damn it. Can this be made undone?
comment:16 Changed 19 months ago by
 Branch changed from u/ghDeRhamSource/3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16 to 3226bc5d5a3d917d7d682ec06f4ff08c49cfbb16
 Commit 761012b122166a5e7b00a05d36dfdf071fd6ecb8 deleted
New commits:
Trac 28921: Simple checks added for _lmul_