Someone had used my credit card number to buy a cell phone. When I saw the charge on my CC statement, I called the cell phone company (can't remember which one it was anymore) and asked what address it went to. Even though they paid for it with my credit card, they said they weren't allowed to provide me with any information. I called my credit card company, got a new card, and told them what I knew. Since the money came out of their pocket and not mine, I assume they didn't quit that easily.
If you look at the context in which I pointed out Knuth's warning, it is appropriate. They were talking about using tools to determine where an application spends all of its time. Also, note the use of the word "premature". Most people would not consider choosing your programming language up front "premature". (Yes, some would.)
What does optimization mean? Well, in this context he's referring to computer resources - memory, cpu (speed), disk I/O. "Premature optimization" in part refers to trading off code complexity for computer resource concerns. It also alludes to the fact that what you think is an optimization might actually end up using more resources. Anyone who has been programming for a significant period of time can tell you stories about cases like that.
What if I need to store a mapping between strings and integers? I could use a list of pairs, or a binary tree, or a hash table. The hash table is probably the most "efficient" of the three, depending on circumstances. But am I sinning by choosing it, when in theory a list of pairs could also work?
If you find using a hash table makes the code much more complicated (even if it makes it faster or use less memory), then that's probably premature optimization. Of course, a list of pairs would actually be more complicated, IMO.
"Don't prematurely optimize" does not mean the same thing as "Pick the slowest of all available techniques."
And here you seem to address all of the concerns you appeared to be raising. You're absolutely right, of course, but I don't know that anyone was suggesting otherwise.
What are the major differences, in your opinion?
on
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· Score: 2, Informative
I used VS professionally for several years before returning to grad school. Perhaps it has improved a lot since then (I used VS6, not.Net), but I don't see any significant differences between it and Anjuta *or* Eclipse. What features do you think are missing from Anjuta or Eclipse?
If you read the Alternative Coagulants section in the Rennet article, you'll see there are quite a few options open to vegetarians. If you are a vegetarian, just check the label. If it doesn't mention how the rennet was harvested, you should assume it came from a calf stomach. However, there are many options available that are vegetarian. Just Google "vegetarian cheese" for several useful sites.
Remember that my calculations were based on the assumption that the pole had a mass of only 100 grams per meter. That means it's either a very thin pole or has a very low density.
Back when we had to write code that would fit in about 590k or so, we would employ all sorts of "tricks" to reduce memory usage. The result was that the code was usually less readable and arguably more complex than it would otherwise be.
If you were to push a 600,000 km pole 4 meters over a period of 1 second, then you've probably exerted a lot of force (pressure) in order to do so. Imagine that the pole weighs 100 grams per meter (i.e., it's fairly light). That pole has a total mass then of 60,000,000 kg. Assume that the force/acceleration is uniform, and you find that 4 meters over 1 second (starting from rest) requires an acceleration of 8 m/s^2. That implies a total force of 480,000,000 Newtons or about 108 million pounds of force. Not surprising that it would shrink a little under so much force...
This seems like an excellent place to remind people that they can opt out of much of that "paper spam". In addition to helping the environment, you're also helping to protect yourself from one vector of identity theft.
However, they do plan on looking for signs of molecular oxygen in the atmospheres of some of these planets. Molecular oxygen is chemically unstable, so its presence is usually considered to be an excellent indicator of life. Not perfect, as it might not be necessary or sufficient, but it's the best method we have right now for detecting M-class planets.
"Also, you'll note that I did couch my original statement with the safety word "might". I'm definitely not claiming this is a settled issue, or even a widely accepted issue - just an interesting new theory"
Suggesting that small forelimbs and massive hind limbs are an adaptation to a semi-aqautic life style when no other known semi-aqautic animal (living or extinct) exhibits such an adaptation isn't a theory -- it's a hypothesis.
Ouch. That hurts because you're exactly right. +10 for you.:)
Anyways, on a related note, did you notice my other post discussing the presence of quasi-evolution in their Creationism museum? I was surprised that it didn't garner even a single response as I found that tidbit to be extremely interesting.
National Geographic has a story on it. If you'll notice, the article says that there is evidence that they were swimming (not wading) in 3m deep water, but that evidence that they were swimming in deeper water would necessarily be absent (if the water is deep enough that they don't leave tracks, then there are no tracks, and it's really hard to study the absence of tracks). Futhermore, other research I've read (I can't find it right now) mentioned that their small forearms were sometimes indicative of species that were adapting to a more aquatic lifestyle. Not conclusive, but definitely an interesting hypothesis (with semi-aquatic, not full-blown aquatic, being the hypothesis). Additionally, with their body shape they couldn't run very fast. If they stumbled at high speeds, their arms wouldn't be able to stop the accompanying 6g deceleration rates.
Also, you'll note that I did couch my original statement with the safety word "might". I'm definitely not claiming this is a settled issue, or even a widely accepted issue - just an interesting new theory. Again, I'm no expert, and I'm not even reading the original journal articles.
I was just arguing that a very large animal can survive on plant matter alone. Furthermore, T-Rex's body might have been suited in part to help it adapt in the water. The tendency towards small forearms is common in animals that have become more aquatic than their ancestors. (Note: the latter supposition is both new and not widely accepted. However, neither should it be considered "fringe".)
Please, please don't get me wrong. I'm definitely not arguing that T-Rex was ever a vegetarian. The part about the teeth is absolutely true. I just felt like getting picky.;)
Its body DOES seem built for, however, chasing down other large creatures.
I'm no longer sure about this. It might have swam down other large creatures. I mean, just look at those pathetic forearms! (I'm also not a paleontologist.)
besides, what plant would be large enough to sustain it?
What plants were large enough to sustain the Brontosaurus?
With the way it walked, I'd have trouble believing it would enjoy bending over to eat grass when getting up off its stomach after a fall would be most difficult
There has been some recent discussion that the T. Rex might have done a lot of swimming...
Take a look at this picture and this one. In order to account for the size of the Ark, they had to stick evolution into the equation. Granted, a greatly sped up, God-directed evolution, but evolution nonetheless.
Although it's rare for a first post to be on topic, this one is. "It's a trap!" refers to the statement made by Admiral Akbar in Star Wars and is a catchphrase often employed on Fark.
I was just referring to the habitable zone as defined by the article I linked to. I do agree that it is overly conservative - depending on the mass/magnetic fields of the planets in questions (and hence the type of atmosphere they're likely to have), planets in the Venus or Mars zone could also contain liquid water. Similarly, planets in the Earth zone might not be able to contain liquid water.
However, if you want to argue that it was 2/8 or even 3/8, then now it's at least 3/249 or 4/249. I.e., the number has gone up by 1.
Before the first exoplanet was discovered the fraction was 1/8 (or 1/9 if you're referring to what we called planets at that time). Still, your point is valid as the fraction is now down to 2/249. Neither Mars nor Venus lie in the habitable zone, although they are both close.
For those not keeping up with the news, Gliese 581 c is the other planet we know of that is in a star's habitable zone.
Slashdot Mirror
(playing off another poster's similar comments)
Would they convict you on successful (as opposed to attempted) suicide?
Someone had used my credit card number to buy a cell phone. When I saw the charge on my CC statement, I called the cell phone company (can't remember which one it was anymore) and asked what address it went to. Even though they paid for it with my credit card, they said they weren't allowed to provide me with any information. I called my credit card company, got a new card, and told them what I knew. Since the money came out of their pocket and not mine, I assume they didn't quit that easily.
If you look at the context in which I pointed out Knuth's warning, it is appropriate. They were talking about using tools to determine where an application spends all of its time. Also, note the use of the word "premature". Most people would not consider choosing your programming language up front "premature". (Yes, some would.)
What does optimization mean? Well, in this context he's referring to computer resources - memory, cpu (speed), disk I/O. "Premature optimization" in part refers to trading off code complexity for computer resource concerns. It also alludes to the fact that what you think is an optimization might actually end up using more resources. Anyone who has been programming for a significant period of time can tell you stories about cases like that.
If you find using a hash table makes the code much more complicated (even if it makes it faster or use less memory), then that's probably premature optimization. Of course, a list of pairs would actually be more complicated, IMO.
And here you seem to address all of the concerns you appeared to be raising. You're absolutely right, of course, but I don't know that anyone was suggesting otherwise.I used VS professionally for several years before returning to grad school. Perhaps it has improved a lot since then (I used VS6, not .Net), but I don't see any significant differences between it and Anjuta *or* Eclipse. What features do you think are missing from Anjuta or Eclipse?
If you read the Alternative Coagulants section in the Rennet article, you'll see there are quite a few options open to vegetarians. If you are a vegetarian, just check the label. If it doesn't mention how the rennet was harvested, you should assume it came from a calf stomach. However, there are many options available that are vegetarian. Just Google "vegetarian cheese" for several useful sites.
Remember that my calculations were based on the assumption that the pole had a mass of only 100 grams per meter. That means it's either a very thin pole or has a very low density.
Back when we had to write code that would fit in about 590k or so, we would employ all sorts of "tricks" to reduce memory usage. The result was that the code was usually less readable and arguably more complex than it would otherwise be.
"Premature optimization is the root of all evil"
Personally, I think all coding should be done using a hex editor and in machine language (none of that fancy assembly - it rots the brain!).
Depending, of course, on how one defines that. Regardless, Anjuta is a great IDE for C/C++ coding and Eclipse is a great IDE for Java coding.
If you were to push a 600,000 km pole 4 meters over a period of 1 second, then you've probably exerted a lot of force (pressure) in order to do so. Imagine that the pole weighs 100 grams per meter (i.e., it's fairly light). That pole has a total mass then of 60,000,000 kg. Assume that the force/acceleration is uniform, and you find that 4 meters over 1 second (starting from rest) requires an acceleration of 8 m/s^2. That implies a total force of 480,000,000 Newtons or about 108 million pounds of force. Not surprising that it would shrink a little under so much force...
This seems like an excellent place to remind people that they can opt out of much of that "paper spam". In addition to helping the environment, you're also helping to protect yourself from one vector of identity theft.
Star Trek IV was the best of them all!
Everyone knows it's the even-numbered versions that are stable...
However, they do plan on looking for signs of molecular oxygen in the atmospheres of some of these planets. Molecular oxygen is chemically unstable, so its presence is usually considered to be an excellent indicator of life. Not perfect, as it might not be necessary or sufficient, but it's the best method we have right now for detecting M-class planets.
Ouch. That hurts because you're exactly right. +10 for you. :)
Anyways, on a related note, did you notice my other post discussing the presence of quasi-evolution in their Creationism museum? I was surprised that it didn't garner even a single response as I found that tidbit to be extremely interesting.
National Geographic has a story on it. If you'll notice, the article says that there is evidence that they were swimming (not wading) in 3m deep water, but that evidence that they were swimming in deeper water would necessarily be absent (if the water is deep enough that they don't leave tracks, then there are no tracks, and it's really hard to study the absence of tracks). Futhermore, other research I've read (I can't find it right now) mentioned that their small forearms were sometimes indicative of species that were adapting to a more aquatic lifestyle. Not conclusive, but definitely an interesting hypothesis (with semi-aquatic, not full-blown aquatic, being the hypothesis). Additionally, with their body shape they couldn't run very fast. If they stumbled at high speeds, their arms wouldn't be able to stop the accompanying 6g deceleration rates.
Also, you'll note that I did couch my original statement with the safety word "might". I'm definitely not claiming this is a settled issue, or even a widely accepted issue - just an interesting new theory. Again, I'm no expert, and I'm not even reading the original journal articles.
I was just arguing that a very large animal can survive on plant matter alone. Furthermore, T-Rex's body might have been suited in part to help it adapt in the water. The tendency towards small forearms is common in animals that have become more aquatic than their ancestors. (Note: the latter supposition is both new and not widely accepted. However, neither should it be considered "fringe".)
Please, please don't get me wrong. I'm definitely not arguing that T-Rex was ever a vegetarian. The part about the teeth is absolutely true. I just felt like getting picky. ;)
I'm no longer sure about this. It might have swam down other large creatures. I mean, just look at those pathetic forearms! (I'm also not a paleontologist.)
Here are two interesting articles on T-rex:
There has been some recent discussion that the T. Rex might have done a lot of swimming...
That said, your basic premise is correct.
Take a look at this picture and this one. In order to account for the size of the Ark, they had to stick evolution into the equation. Granted, a greatly sped up, God-directed evolution, but evolution nonetheless.
You can't clog Wikipedia. See, it's not actually tubes...
(And no, I don't.)
Although it's rare for a first post to be on topic, this one is. "It's a trap!" refers to the statement made by Admiral Akbar in Star Wars and is a catchphrase often employed on Fark.
I was just referring to the habitable zone as defined by the article I linked to. I do agree that it is overly conservative - depending on the mass/magnetic fields of the planets in questions (and hence the type of atmosphere they're likely to have), planets in the Venus or Mars zone could also contain liquid water. Similarly, planets in the Earth zone might not be able to contain liquid water.
However, if you want to argue that it was 2/8 or even 3/8, then now it's at least 3/249 or 4/249. I.e., the number has gone up by 1.
Before the first exoplanet was discovered the fraction was 1/8 (or 1/9 if you're referring to what we called planets at that time). Still, your point is valid as the fraction is now down to 2/249. Neither Mars nor Venus lie in the habitable zone, although they are both close.
For those not keeping up with the news, Gliese 581 c is the other planet we know of that is in a star's habitable zone.