It all depends on what you want to do with your matrices. Various operations have various costs in different sparse matrix formats. The standard ones are COO or coordinate format: a list of triples (i, j, val); DOK or dictionary of keys format: the hashmap you are thinking of; LIL or list of lists format: a list for each row and a list if pairs (j, val) in each list entry; CSR/CSC or compact sparse row/column: an array of indices where each row starts, an array of column indices and an array of values.
COO and DOK are great for changing sparsity structure; LIL is very useful if you have a lot of row-wise (or column-wise) operations, or need to manipulate rows regularly. CSR is great for matrix operations such as multiplication, addition etc. You use what suits your usecase, or change between formats (relatively cheap) as needed.
It would be great if that were true, but it probably isn't in the long run. Children don't have to consent to lots of things that happen to them now. There are other societies that have or have had child brides, so there are obviously social mechanisms to enable that. With diversity and immigration policies brining in more and more people from those societies I wouldn't be surprised if they considerably outnumber the gay population now. That is before you even consider traditional pedophiles. Over time advocates for minor-adult sex will have more political power. Speaking of political power, I hear there is a former Speaker of the House paying millions in hush money over sex with a minor decades ago. Besides, there are 50 years of prep coming to enable it, academicians working on normalizing minor-adult sex now, just as there were people doing that for homosexuality decades ago. In some parts of society, such as Hollywood, powerful people are known as child abusers, and nothing is said. Fifty years ago homosexual marriage couldn't happen. Today child marriage "can't happen," but that isn't likely to remain true as things stand. Standards were destroyed to enable homosexual marriage, they won't magically reappear when needed to stop child marriages.
You sound more Randian than Christian.
Why wouldn't I? Christianity is like chess. It's all there, in plain view, the whole time. Countries are more like poker, bluffing and cheating like. .
There is a way which seemeth right unto a man, but the end thereof are the ways of death.
Tearing down walls is always a good thing.
Is it OK if I just hope you are proven correct, while kinda knowing that this story goes another way?
Our OS who art in CPU, UNIX be thy name. Thy programs run, thy syscalls done, In kernel as it is in user!
