rtoy
commented
2 months ago Imported from SourceForge on 2024-07-07 00:12:44 Created by robert_dodier on 2021-09-15 22:40:30 Original: https://sourceforge.net/p/maxima/bugs/3854/#37e6
- labels: --> share packages, ctensor
- Description has changed:
Diff:
--- old
+++ new
@@ -1,22 +1,22 @@
This is the original function:
-
+```
frame_bracket(fr,fri,diagframe):=block
(
for a thru dim do for b thru dim do for c thru dim do
fb[a,b,c]:sum(sum(fr[a,e%]*(diff(fri[e%,c],ct_coords[f%])-
diff(fri[f%,c],ct_coords[e%]))*fr[b,c],e%,1,dim),f%,1,dim)
);
-
+```
The last fr term needs to be summed with f% in the last index c.
This is the corrected function:
-
+```
frame_bracket(fr,fri,diagframe):=block
(
for a thru dim do for b thru dim do for c thru dim do
fb[a,b,c]:sum(sum(fr[a,e%]*(diff(fri[e%,c],ct_coords[f%])-
diff(fri[f%,c],ct_coords[e%]))*fr[b,f%],e%,1,dim),f%,1,dim)
);
-
+```
That attached picture is from the maxima manual section 26.2.4 Frame fields.
This should make it equivalent to the attached formula except for the index c.
Imported from SourceForge on 2024-07-07 00:12:43 Created by richardgobeli on 2021-09-15 22:23:15 Original: https://sourceforge.net/p/maxima/bugs/3854
This is the original function:
The last fr term needs to be summed with f% in the last index c. This is the corrected function:
That attached picture is from the maxima manual section 26.2.4 Frame fields.
This should make it equivalent to the attached formula except for the index c. Where the summing index e% is like e in attached picture and summing index f% is like d in attached picture.
Also the above formula calculates a covariant tensor where a, b and c are all lower indices and the itensor package has the frame bracket defined with c as an upper index. I don't know if this will have an issue with the ic_convert function. Is the manual correct in the position of the c index?
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