Skip to main content

Timeline for Sparse block matrices all wrong

Current License: CC BY-SA 4.0

18 events
when toggle format what by license comment
Jun 5, 2018 at 8:12 history tweeted twitter.com/StackMma/status/1003912373097390080
Jun 5, 2018 at 7:40 answer added kglr timeline score: 3
Jun 5, 2018 at 7:23 comment added Henrik Schumacher Let us continue this discussion in chat.
Jun 5, 2018 at 7:22 comment added მამუკა ჯიბლაძე @HenrikSchumacher Yes, what confused me is the very existence of ArrayFlatten - I thought it was precisely for such cases. While in fact it seems to become arrayflattened from the beginning...
Jun 5, 2018 at 7:18 comment added Henrik Schumacher Ah, this last command actually gave me a hint on what you were thinking how it should work.
Jun 5, 2018 at 7:08 vote accept მამუკა ჯიბლაძე
Jun 5, 2018 at 6:46 review Close votes
Jun 5, 2018 at 6:56
Jun 5, 2018 at 6:44 answer added Henrik Schumacher timeline score: 9
Jun 5, 2018 at 6:34 comment added მამუკა ჯიბლაძე Tried this too. Now (with the new example that I replaced the old one with) the first two rows are ok; however the first rows of other blocks still become chopped off by some reason, and these blocks are shifted up. And I still believe that dimensions of sa must be {n, n}, it is ArrayFlatten[sa] that must have dimensions {Total[dim], Total[dim]}, not sa itself, no?
Jun 5, 2018 at 6:30 history edited მამუკა ჯიბლაძე CC BY-SA 4.0
more revealing example
Jun 5, 2018 at 6:30 comment added Henrik Schumacher Then you should use Total[Most[dim]] + 1.
Jun 5, 2018 at 6:28 comment added მამუკა ჯიბლაძე Maybe actually I will replace the example with this one, it is more illustrative...
Jun 5, 2018 at 6:27 comment added მამუკა ჯიბლაძე @HenrikSchumacher Now it gives correct answer. However with, say, dim = {2, 3, 4} it is all wrong again. As for your explanation: it should be an $n\times n$ array of matrices, should not it?
Jun 5, 2018 at 6:24 comment added Henrik Schumacher Then try Band[{1, n (n - 1)/2 + 1}]. The second index of the band of the last matrix should the sum of the dimensions of the others +1
Jun 5, 2018 at 6:21 comment added მამუკა ჯიბლაძე @HenrikSchumacher Tried. Wrong again (in a different way) - among other things, it is not square anymore. Besides, I don't see why should it be placed there...
Jun 5, 2018 at 6:14 comment added Henrik Schumacher Shouldn't the last matrix be placed on Band[{1, Quotient[n (n + 1), 2]}]?
Jun 5, 2018 at 6:12 history edited მამუკა ჯიბლაძე CC BY-SA 4.0
added 57 characters in body
Jun 5, 2018 at 6:02 history asked მამუკა ჯიბლაძე CC BY-SA 4.0