First: I'm sorry to hijack this thread and veer offtopic so hard. But none of these alternatives solves the rounding problem (which is fundamental; some numbers simply can't be represented precisely in finite). The only solution is to deal knowingly with the problem and especially to round only for the presentation and for the end results, never for intermediary results. That's not he problem at all. The problem is that numbers less than 0 which can be represented exactly in decimal system, not always can be represented EXACTLY in binary. Sure, you can have double and quadriple precision and perhaps make some sort of checks which will treat numbers like 0.29999999999999 as 0.3, but that's more like workarounds. The only right way to do financial software is exact decimal types.This is owed to the fact that the financial world uses decimal. If these guys weren't bankers but mathematicians, the only right way to write software for them would be to use some certain kind of symbolic expressions. Side-note: Back when I joined Bitcoin there was some dude on irc (forgot his name, he might still be around) constantly trying to convince people we should use a kind of base-16 number system (not hexadecimal, but similar, I forgot the name, some other bloke tried to convince people in britain in the 19th century to use it and failed) for bitcoin. That would've clearly prohibited any sort of success for bitcoin in my mind. You often hear "floatinig point is evil". Mostly this is an urban legend.
Floating point numbers can be dangerous only when used naively.
More specifically, there is a standard-type of floating point number in many programming languages, which is often called "float". The key point is that this number type uses only the so called single precision (3 bytes mantissa, 1 byte exponent). This is enough to represent roughly 4 places without error. And this is indeed not sufficient for financial math.
I agree that the problem is not using floating point but storing/calculating in binary and displaying in decimal. The fact that "some numbers" cannot be represented with finite number of digits is not very relevant. While this - apart from numbers like sqrt(2) or sqrt(-1) - includes some commons numbers like 1/3, you're unlikely to encounter these numbers in this setting (because they can't be entered in decimal by a user). Of course it might pop up when you're trying to make 3 slices from one pizza or something (1 pizza is a financial unit now, I hear), but usually you just give everyone 0.33 pizzas and pocket the remaining 0.01 yourself in such a case. I also agree this is pretty much a non-issue (just using double precision and rounding only at display time should work in most cases) I'm not sure the concerns about speed of floating point decimals are an issue either. In a database-heavy app you usually have other performance bottlenecks that are much more severe. Maybe it's interesting to note that IBM (used to) put decimal floating point arithmetic instructions into some of their CPUs: http://www.ibm.com/developerworks/wikis/display/hpccentral/How+to+Leverage+Decimal+Floating-Point+unit+on+POWER6+for+LinuxI'll try to honor Ichthyos advice. But none of these alternatives solves the rounding problem (which is fundamental; some numbers simply can't be represented precisely in finite). The only solution is to deal knowingly with the problem and especially to round only for the presentation and for the end results, never for intermediary results.
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I'm getting a little tired of buyers that make contact with me, offer to purchase bitcoin, agree on a time and location to meet, and then never show up.
It costs me time and money (gasoline) to drive to the meeting location and wait around for someone who never shows.
Why don't they show up? Because the price has dropped? If that's the case, why not make the price on the spot instead of using the locked-in price? EDIT: Sorry, just read you're offering that. What jerks to not even cancel the deal and just not show up... |
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I dont think your method is correct. This is the method I used to satisfy myself that a oplatinum ring was truly pure.
a) Weigh Ring.
b) Weigh ring under water.
This can be done by suspending the ring on a frame such that it hangs from a thread, and is imersed.
c) As an alternative to b), weigh the difference in weight between b) and a) , many scales can do this automatically.
Either way, you have the in air weight , and the loss of weight from imersion in water, c.
Hmm. I think this is what I did, no? What's the difference? His test relies on more implied concepts of physics. Mainly Archimedes's bouyancy principles. This helps to get rid of errors in weighing or measuring the volume of the displaced water. My method also used the bouyancy principle and find the volume of the coin by "weighing" the displaced water. I also suspend the coin from a thread. I don't see how his method differs at all from what I did, practically. Am I overlooking something? |
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damn. I keep making dupes. What is wrong with my bitcointalk searching skills? yeah, i'll second that  you didn't even know who Trace Mayer was!!! haha. lol. While we're at it.. what's that Bitcoin-thing everyone's on about around here? |
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damn. I keep making dupes. What is wrong with my bitcointalk searching skills? |
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I'm actually not in the process of selling my metal. I'm content with what I currently have. I thought the issue might be to ship single (or at least very small quantities) of coins to people as prize for some games on taabl.net. I thought I might be of help somehow (and make a little profit maybe) because I seem to have good shipping options available. I could've maybe stored (or bought) some silver from rpietila for this purpose and provided shipping service.
Why is 0.3 BTC too high a shipping price for 25 rounds? The low price and VAT-exclusivity of rpietila will surely outweigh any shipping cost at such quantity, no?
It isn't too high at all. As I mentioned I was thinking about much smaller quantities when I first asked about it, and your offer would be great for that. I have changed my mind and am just waiting for confirmation that the 0.3 BTC is applicable today and for the specified quantities. cool |
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"IF THE MARKET MANIPULATOR WANTS TO DISTRIBUTE (DUMP) HIS SHARES, HE WILL START A GOOD NEWS PROMOTIONAL CAMPAIGN."
Is this why this thread was started?
I don't think so. Also: Bitcoin is not a stock. |
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on a side-note: whatever happened to "don't use floating point for financial apps"? ;-)
No floating point are used here, nowhere  I see numbers like 349.99999 and 1490.00008 regularly. I figured those were floating point artifacts. |
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@rpietila: Thanks! I only saw your post now, is the offer valid for today and for quantities 10~25? @molecular: well, I'm always torn about this. I want to hold on to my BTC, I want to put my BTC to use, I want metals for myself, I want metals for TAABL.net. I guess I'm a little schizophrenic, but aren't we all? Anyway, I was thinking of getting a couple to test the waters, but now I'm thinking of 10 to 25 rounds. How often I would buy again depends deeply on how well the lotteries are received. Do you have those many that you want to part with? I'll reach some sort of decision soon as I wanted to place an order today. Also, do you have any gold for sale? I'm actually not in the process of selling my metal. I'm content with what I currently have. I thought the issue might be to ship single (or at least very small quantities) of coins to people as prize for some games on taabl.net. I thought I might be of help somehow (and make a little profit maybe) because I seem to have good shipping options available. I could've maybe stored (or bought) some silver from rpietila for this purpose and provided shipping service. Why is 0.3 BTC too high a shipping price for 25 rounds? The low price and VAT-exclusivity of rpietila will surely outweigh any shipping cost at such quantity, no? |
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I dont think your method is correct. This is the method I used to satisfy myself that a oplatinum ring was truly pure.
a) Weigh Ring.
b) Weigh ring under water.
This can be done by suspending the ring on a frame such that it hangs from a thread, and is imersed.
c) As an alternative to b), weigh the difference in weight between b) and a) , many scales can do this automatically.
Either way, you have the in air weight , and the loss of weight from imersion in water, c.
Hmm. I think this is what I did, no? What's the difference? |
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There's definitely a good bit of error there, which I really doubt since the coins at minted by respected sources. Those coins are probably either .999 or .9999 and that thousandth or ten thousandth of an percent does not result in a 1-2% error.
Still would catch most real fakes as the density would be off by more then 5%. What density could a fake have? What kind of materials/techniques might be used? A bigger water container could help, and maybe a more accurate scale. Finally having a consistent amount of string in the water and taking that into the calculation would help.
I thought about that. I think lowest hanging fruit would be a better scale. I can't use more water, scale can only do 200g. |
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There's definitely a good bit of error there, which I really doubt since the coins at minted by respected sources. Those coins are probably either .999 or .9999 and that thousandth or ten thousandth of an percent does not result in a 1-2% error.
with error I meant error of my measurement. |
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It's a money processing service. Big fucking money processing. Such processor behavior is Asolutely/Definately/Really/Surely NOT ACCEPTABLE.
And yet the next minute we go there and trade. |
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Cool idea. The best would be a vanity address.. quicker to quote over the phone.
Yeah, just get a vanity address, then use the firstbits. or use (something like) https://btc.to/ |
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on a side-note: whatever happened to "don't use floating point for financial apps"? ;-)
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Well, if everyone agree with you I'll revert this change. What do you all think? Thanks for the feedback ² I don't have a problem scrolling the page. I'm for ungrouping or grouping to 1% increments. |
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Hello everyone, First, legal news. If you go to http://www.icris.cr.gov.hk/csci/ (the official Hong-Kong registry site), you will find us under the name "Bitfinex Limited" (search as a unregistered user). The reason we didn't announce it yet is that the company has not yet official taken over the activity of the website, and we are still in the process of finding a bank account. This is unexpectedly hard, and to be honest, this is driving me mad. Anyway I'll probably fly myself to Hong-Kong to get things done... Furthermore, MTGOX code deposit don't always work, for some reason (related to timeout it seems). So you can be assured that we are doing everything we can to speed up the process a finding a bank account to accept deposit. I'll update the website to reflect this last changes. Now, about the lending page: to compact offers a bit, I've decided to group them by 10% rate asked. Now the fact that I round them to the upper 10% for loans demands is maybe not the wisest choice, I'll see if I can change that. If you don't find it more useful than the previous page, just tell me and I can reverse the change; Best regards, Raphael This is good news about the incorporation. Thanks for thinking about the lending page. Let's see how it goes. Good luck getting a bank account. One wouldn't think it should be problematic... but what do I know. |
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Agree. I cannot give graphs for AML requests right now, but I can tell you that the rate of new requests increased in the same way, with around 1000 new requests on Friday. Three new staff will be starting Monday on the AML.
Just checked the queue, there are 5500 accounts pending verification at this very moment.
If it's not bullish, I don't know what is... Do you need a verified account to deposit fiat? |
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There are 4000+ accounts in front of me waiting to be verified, so more staff sounds like a good idea  Does one need a verified account to be able to deposit fiat or just to withdraw? |
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100 next week is getting more probable by the minute. holy crap! |
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