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Comment: Re:Kids don't understand sparse arrays (Score 1) 128 128

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.

Comment: Re:a low-IQ child's IQ can be raised in some cases (Score 2) 185 185

I've had sat psychologist administered IQ tests a year apart and had my score differ by 10 points. I've been told that, in fact, this is perfectly normal and well within the accuracy expected of IQ tests by psychologists who take them seriously. I wouldn't worry about IQ scores changing (they may well do that, but it is equally likely measurement error). IQ is a very imperfect measure to begin with. Our ability to measure it, even under the best of conditions, is extremely poor. Take most IQ studies with a grain of salt.

Comment: Re:Consulting (Score 1) 203 203

In a couple of major companies where I worked, I archived all my code before leaving, burned them to CDs, and gave two copies to my manager. And I kept a copy for me. I copied them on my home discs, automatically backed up, and left them there.
In both case, the companies lost the copies, and came back to me offering money - years later. And yes, I took it!

It's a sensible idea to have offsite backups - and taking copies home is a good way to do that. Could be illegal, theoretically, but really, what would you do with this specialised stuff? But it certainly is useful to the original company.

So take copies of all the emails, and leave good contact details with your manager, their manager, and if possible for your replacement, and offer a support rate of - say - double your current rate (don't mention that to your replacement). Make it a daily rate, not hourly.

Comment: This doesn't affect anonymity (Score 0) 50 50

If I understand correctly, this attack has a similar effect to a DNS attack : you replace a server for an address with one of your own servers instead, so that users requesting the service will be routed to you.

While this is bad, I'm not sure how it affects anonymity in any way. Obviously, the spoofed service might try to serve some Tor vulnerability to the users to identify them, but this relies on finding an actual weakness in Tor, or in the user's setup, to identify them.

Comment: Re:The Road Warrior (Score 1) 776 776

...not a sequel, but a cash-in remake.
It's not a Mad Max movie. The main character isn't Max, the atmosphere isn't Mad Max's, it just happened to have spiked cars chasing plated cars in the wastland.

Indeed. What they should have done was get the writer/director of the original film, who I gather had been trying to get a sequel made for over a decade, to come and write and direct the new one. Clearly whoever they got to write this didn't really understand Max's character at all.</sarcasm>

Comment: Java *IS* slow (Score 1) 386 386

I agree with most of the submitter's points, except for the "if Java is slow for your then you aren't using it right". Sure, if all you're doing is a tightly optimized PI calculation simulator, Java can match (or even, in some cases, beat) C/C++ performance. In a real-world user application though, it falls apart. I have never, ever used client-side Java application that wasn't a huge RAM and CPU hog. All you need to do is look at any big client-side Java application to realize that. Practically anything that has a user GUI is a disaster. Case in point : Eclipse, Open/LibreOffice. If it runs on Java, it's on that list.

Java works really well for some server workloads with well-defined inputs, processing, then output. Anyone using Java to develop client GUI apps is using the wrong tool for the job. I'm looking at you, Cisco (ASDM, SDM, Network Assistant, etc).

I used to be a huge java on the desktop proponent, but the end results have since changed my mind. Show me a few large desktop applications that aren't slow and painful to use and maybe I'll change my mind. Until then, please stop using Java on the client side.

Comment: Re: Solar rarely enough for the whole house (Score 1) 299 299

That depends where you're living. Here in Quebec, 90% of homes are heated using electricity, because it's cheap thanks to our huge hydro resources. In the winter, it's usually too cold for heat pumps to work. To give you an idea, here in Montreal, average temp for last february were -19C (-2F). A heat pump can save a bit during fall or spring, but usually the savings aren't worth the purchase & maintenance cost of the pump. It's all resistive heating.

Comment: Jury Nullification? (Score 3, Interesting) 197 197

Clearly "what the people want" isn't working here. So why don't they simply sell the cars direct there anyway and disregard the law? Although I could not find a poll for Virginia, a Texas poll showed 85% of people in favor of allowing direct-to-consumer sales of cars. It would seem near-impossible to get a unanimous verdict to convict, as is required in Virginia.

Comment: Re:Check their work or check the summary? (Score 2) 486 486

And this is why we should not teach CS101 in Java or Python. If they'd been forced to use C this whole experiment would have turned out differently.

Not at all. If you wrote your C in memory string handling as stupidly as they wrote the Python and Java you will still get worse performance in C (e.g. each iteration malloc a new string and then strcpy and strcat into it, and free the old string; compared to buffered file writes you'll lose). It's about failing to understand how to write efficient code, not about which language you chose.

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