Bugzilla – Bug 1265
HouseholderQR description and example do not match.
Last modified: 2016-08-22 21:27:54 UTC
HouseholderQR states that .solve() for a matrix b in solving Ax=b is not yet implemented, specifically:
The case where b is a matrix is not yet implemented. Also, this code is space inefficient.
But, the example provided to solve mx=y uses all 3x3, returning the text:
"Here is the matrix m:
0.68 0.597 -0.33
-0.211 0.823 0.536
0.566 -0.605 -0.444
Here is the matrix y:
0.108 -0.27 0.832
-0.0452 0.0268 0.271
0.258 0.904 0.435
Here is a solution x to the equation mx=y:
0.609 2.68 1.67
-0.231 -1.57 0.0713
0.51 3.51 1.05
So, I conclude that either:
1) The documentation is lagging the code, and the Note should be removed or corrected to describe the actual limitations on RHS when solve'ing.
2) The example was re-used (from some other .solve() usage) to show the interface, but should be modified to show a vector y.
3) I just didn't understand correctly...in which case I apologize.
I followed the link to "development branch documentation", which shows 3.2.93, and that was the same as the 3.2.9, with the inconsistency described above.
Thank you for the generally excellent documentation!
You can generally be certain the code snippet is working and the given output is the actual output of the operation (we compile the snippets and run them when generating the documentation).
> 1) The documentation is lagging the code, and the Note should be removed or
> corrected to describe the actual limitations on RHS when solve'ing.
I'm not sure however, what is (or was) meant by "space inefficient" here.
Quite likely this is obsolete as well (at least for the 3.3 branch).
Also, this seems to be outdated for some other decompositions, too.
Those notes are obsolete: