ealloc

> [if] you want to retain as much precision as possible and still use floats, don't store it in a float with range [0.0,100.0]. Store it with the range [0.0,1.0].

I just tested this out and it doesn't seem true.

The two storing methods seem similarly precise over most of the range of fractions [0,1], sometimes one gives lower spacing, sometimes the other. For instance, for fractions from 0.5 to 0.638 we get smaller spacing if using [0,100], but for 0.638 to 1 the spacing is smaller if storing in [0,1].

For very small fractions (< 1e-38), it also seems more accurate to store in the range [0,100] since you are representing smaller numbers with the same bit pattern. That is, because the smallest nonzero positive float32 is 1.40129846e-45, so if you store as a float32 range [0,1] that's the smallest possible representable fraction, but if you're storing as a float in range[0,100], that actually represents a fraction 1.40129846e-47, which is smaller.

For the general result, see for yourself in python/numpy:

    x = np.linspace(0,1,10000)
    plt.plot(x, np.float64(np.spacing(np.float32(x*100)))/100)  # plot spacing stored as [0,100]
    plt.plot(x, np.float64(np.spacing(np.float32(x))))  # plot spacing stored as [0,1]

How is CUDA-C that much easier than OpenCL? Having ported back and forth myself, the base C-like languages are virtually identical. Just sub "__syncthreads();" for "barrier(CL_MEM_FENCE)" and so on. To me the main problem is that Nvidia hobbles OpenCL on their GPUs by not updating their CL compiler to OpenCL 2.0, so some special features are missing, such as many atomics.

Did you read in English? I read it in french and loved it, then looked at Montcrief's translation - I would not have made it through. Montcrief turned Prousts clear and precise (but long) sentences into a kind of esoteric word puzzle. Lydia Davis' translation looked much better.

For War and Peace, I didn't know russian, so I tested different translations before going ahead. The translator makes a big difference, I found some translations hard to read.

I had your feeling with Ulysses, though. No translation issue there. Couldn't make it very far.

That would be a straight-up, avoidable software/hardware bug: The incoming timestamp is incorrect, and garbage in is garbage out.

That would make me curious how the timestamp error occurred: software, hardware? Camera or Navigation code? I assume they have very high standards, what was the process failure point?

The article says the problem was a dropped frame from the camera, but that just further piques my curiosity:

Presumably they use some kind of Kalman Filter, but those are easy to program to account for missing frames, or frames at non-discrete timepoints, perhaps even for screwy camera images if the programmer had a reasonable prior for the likelihood of it happening. Kalman Filters by design account for measurement error.

Sperm cells can be seen as a haploid phase of many organisms' lifecycle, so are alive by pretty much any definition.

In humans, the haploid phase of the lifecycle is single-celled, while the diploid phase is multicellular. In contrast, in mosses and fungi the haploid phase is multicellular while the diploid phase (sporophytes/zygote) is single-celled.

Red blood cells are discussed in the article.

It may be coming back though.

IBM's new and rising supercomputer architecture, POWER9, supports hardware IEEE binary128 floats (quad precision). Their press claims the current fastest supercomputer in the world uses POWER9.

The ppc64 architecture (still produced by IBM) supports "double-double" precision for the long-double type, which is a bit hacky and software-defined, but has 106 bit mantissa.

And ARM's aarch64 architecture supports IEEE binary128 long-doubles as well, though it is implemented in software now (by compiler). Maybe they plan a hardware implementation in the future?

Yes, forces transmitted through fields act "at a distance", but is that really "spooky"? Do you think it is "spooky" that if you make a wave at one end of a pond, the wave reaches the other end? I don't. I consider the propagation of waves to be a "local" non-spooky phenomenon.

Disturbances in a field propagate through space similarly. A disturbance of the field at a point only affects the value of the field in the immediate spacetime surroundings, just like a water wave. I would call that "local" and non-spooky. Whether or not there is "mechanical contact", whatever that means, is irrelevant.

This is in contrast to Newton's theory of gravity, where the force of gravity was spookily felt instantaneously across space.

I've read Chomsky's opinion on this before in his essay ""Science, Mind, and Limits of Understanding", and I think he misunderstands the physics.

He seems to think Newton accidentally disproved the concept of locality through his theory of gravity. It's true that philosophers largely gave up on locality in the 18th century because of Newton, but that was only temporary: In the 19th century the principle of locality came back with a vengance after Maxwell.

Today the principle of locality is a key component of the Standard model: The Hamiltonian of the standard model is local, meaning you can compute what happens at a point in spacetime knowing only what is going on in an infinitesimal region around it. Even outside the standard model, LIGO proved that graviational waves exist, and therefore gravity is a local phenomenon.

Einstein was famously prepared to give up on quantum mechanics because it seemed to violate the principle of locality, which he thought was more important. That is still debated sometimes, though whether quantum nonlocality exists seems to be a matter of interpretation and is also different from the kind of locality chomsky is talking about. Locality is still a key principle in physics.

I use a huge amount of open-source software which I do not believe is subsidized.

Some is, eg some linux/gnome devs are paid to contribute. But many smaller projects/components are volunteer-only.

> Universities will just start offering education for free instead of waiving the tuition

Aren't you supposed to be taxed on the value of a good/service/gift received even if it was given to you for free? What is the "true value" of tuition?

I don't think waiving tuition will work, assuming tuition is taxed like most other things.

The book was written in 2002, and I just looked up Nick lane's latest 2016 take on it here: [1]

His point in this new article is that instead of one big "oxygenation event" there may have been multiple. But he sticks to his story that the creation of an ozone layer by photosynthesis was the key step in saving the oceans. He argues both Mars and Earth had oceans originally (confirmed by Mars Satellite observations), which were gradually diminished by a process in which ultraviolet light splits atmospheric water, minerals on the surface absorbed the oxygen (rusting, making Mars red) leaving the hygrogen to blow away. But life on earth pumped extra oxygen into the atmosphere, faster than minerals could aborb it, creating the reactive ozone layer which prevented hydrogen from blowing away, thus saving the oceans from their fate on Mars.

[1] nick-lane.net/wp-content/uploads/2016/12/Oxygen-and-life.pdf

The reason water exists on earth, and not on mars, may be that life on earth saved the water by discovering photosynthesis.

The discovery of photosynthesis caused the "great oxygenation event" which pumped oxygen into the atmosphere. Oxygen reacts with atmospheric hydrogen to form water. Without the oxygen, the very light hydrogen molecules would float to the top of the atmosphere and are easily blown away by solar winds, which is what happened on Mars. But with high oxygen concentrations on Eath, hydrogen molecules react to form heavier water molecules before they have a chance to be blown away, and thus hydrogen and water are retained.

I read about this in the book "Oxygen" by Nick Lane.