Bitcoin Forum

Bitcoin => Mining speculation => Topic started by: jwcastle on September 20, 2014, 05:52:49 AM



Title: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: jwcastle on September 20, 2014, 05:52:49 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: pandalion98 on September 20, 2014, 05:55:02 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

It reached somewhere $390 a few hours ago.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: jwcastle on September 20, 2014, 05:59:24 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

It reached somewhere $390 a few hours ago.

substitute OMG for OMFG! :P


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Remember remember the 5th of November on September 20, 2014, 06:02:27 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

It reached somewhere $390 a few hours ago.

substitute OMG for OMFG! :P

It went even lower than that, to 376, somebody said.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: jwcastle on September 20, 2014, 06:04:09 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

It reached somewhere $390 a few hours ago.

substitute OMG for OMFG! :P

It went even lower than that, to 376, somebody said.

I think the only thing left to say is: Game over. Game over dude!


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: cdog on September 20, 2014, 06:15:49 AM
The mining situation is excruciatingly tight right now, the margins are gone for everyone except the hardware manufacturers who are receiving chips from the foundry and assembling the ASICs themselves.

Litecoin as well which just hit 1 Petahash - an unthinkable amount 1 year ago. Its pretty simple - if you arent the one ordering the wafers, you arent in the mining business, you are hobby mining.

Price isnt related to anything else other than adoption, if the adoption rate is mostly flat the price mostly stays in a range slightly above the cost of mining it. If people arent increasingly using BTC then the price goes flat/down, and miners leave the game as they get squeezed out with razor thin margins, which is what we are seeing now - all the small players and weak hands being forced out of Bitcoin.

The more people who use BTC and LTC, the more useful and therefore more valuable they become. A lot of people who were just in it to make some quick cash mining got seriously burned, and in my view having this group out of Bitcoin is for the best, the sooner the better. The miners who really care about crypto arent in it for purely financial motives and they wont be going anywhere, but I would imagine there is a lot of liquidation and consolidation among mining firms going on currently - maybe even with our friends at Eclipse? ;-)


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Lauda on September 20, 2014, 06:23:09 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

It reached somewhere $390 a few hours ago.

substitute OMG for OMFG! :P

It went even lower than that, to 376, somebody said.

I think the only thing left to say is: Game over. Game over dude!

Mining was not profitable in the past many times. No, it's not game over.
The increasing hashrate means that there is confidence from the people mining (be it the big or little guys).
The hashrate increase does not = price increase. That way of thinking is wrong. Anyhow the price seems $18 up for now.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Kprawn on September 20, 2014, 07:01:54 AM
I sometimes wonder, if this was the will of Satoshi, to only have a few big companies, rule the mining scene.  >:(

When it started out, everyone with a GPU could mine, now it's only a few hobby miners, with nearly zero % change of finding and mining a block.

Yea, He had the vision, that CPU/GPU power would increase, BUT I cannot see, that he wanted a decentralized P2P network that was inaccessible to the general solo miners out there.

If you don't have a shitload of money, you are basically out of BTC mining.  >:(


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: kamudimana on September 20, 2014, 07:10:44 AM
i'm dying with new 150GH/s that i bought last week, damn shit  :(


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: keithers on September 20, 2014, 07:11:17 AM
I dont mine, but it seems only logical that as the difficulty keeps going up, miners will not want to sell their BTC or LTC at a loss...


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: haploid23 on September 20, 2014, 07:36:12 AM
I mined with a few GPU's back in 2011, stopped because I got busy and moved on to other things. Started again with scrypt GPU's at the end of last year. Stopped again after scrypt ASICs hit the scene. Now recently just bought 2x S1 antminers just to tinker, no profit in mind of course. By now I think it's impossible to ROI with these old hardware, assuming free electricity.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Waramp22 on September 20, 2014, 07:54:25 AM
When it started out, everyone with a GPU could mine, now it's only a few hobby miners, with nearly zero % change of finding and mining a block.

Yea, He had the vision, that CPU/GPU power would increase, BUT I cannot see, that he wanted a decentralized P2P network that was inaccessible to the general solo miners out there.

If you don't have a shitload of money, you are basically out of BTC mining.  >:(

Perhaps a CPU only or X11 coin will be the future, but for now it is bitcoin.

Keep in mind that back when the early guys were mining with CPUs/GPUs, they would get 25btc every few days/weeks/months but people forget that it wasnt worth anything. Satoshi wasn't living in vegas living the high life. Those guys mined for a hobby and had the foresight to hold for the future.


Back Then
28btc X $0.55 = $15.40

Now
.0385193btc X $400 = $15.40

If you are in it to make a profit right now, don't bother. If you have faith in bitcoin, you will hold for the future. One day you will look back to today and think "what the hell was a whining about!!!! If only i had known bitcoin would be worth $5000 each i would have invested more!"

Notice how people whine on these forums? "If only i had discovered bitcoin in 2011 i would be rich!" They forget that in 2011 it was not be profitable to mine bitcoin. (fiat speaking) This is where we are right now.  


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: OrientA on September 20, 2014, 08:41:32 AM
i'm dying with new 150GH/s that i bought last week, damn shit  :(

Is not that hash rate too small?


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: haploid23 on September 20, 2014, 08:47:35 AM
If you have faith in bitcoin, you will hold for the future.

No, if you had faith in bitcoin, you would spend them like their intended use. Then replenish what you spent. If not a single person spent them, there would be zero growth.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: jwcastle on September 20, 2014, 03:58:38 PM
Making money is a good incentive for people to stay in the game.
But to throw money away only to justify that you are helping the crypto currency movement is absurd.

Why bother mining if you know that every day your machine is on, you are losing money.
Example: Your machine makes 1 BTC every week on average. After considering electricity and hardware costs (calculated in BTC), you are netting 0.8 BTC

If you buy some BTC through an exchange, you have not lost anything unless the exchange rate goes down. This is a far better option for someone who has faith in the future of BTC and want to hold the BTC they mine/buy.
Example: You buy 1 BTC every week. You still have that 1 BTC without spending money on electricity or hardware.



Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: mmeijeri on September 20, 2014, 04:47:07 PM
If you can't mine and hold, you need to get out.

If you want to hold and it's cheaper to buy than to mine, then the rational thing to do is to buy. If mining is cheaper, then mining and selling off the proceeds is the rational thing to do. The two processes are independent. You can always buy however much you intend to hold with the proceeds of mining.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Nagle on September 20, 2014, 06:16:50 PM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
There are two popular difficulty estimators on line, and they both suck. One always underestimates, and one always overestimates. As the next adjustment gets closer, they converge. Someone needs to write a better one, and back-test it against the historical data.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: philipma1957 on September 20, 2014, 09:51:23 PM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
There are two popular difficulty estimators on line, and they both suck. One always underestimates, and one always overestimates. As the next adjustment gets closer, they converge. Someone needs to write a better one, and back-test it against the historical data.
  yeah but really going nuts for 1 diff jump is meh.  I do 200 day slots and look at longer trends.


from now until jan 1 around 100 days should prove very interesting with big swings in price and diff.  the last 100 days we were pretty stable about 10% a diff jump and price was around 420 to 640 usd a coin.

 I see bigger swings in price. but wtf do i know?


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Puppet on September 20, 2014, 10:25:02 PM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.

Ahm, no. The current network speed increase has to continue in order for us to hit the estimated ~35B. 40B just isnt going to happen this round, even if the growth accelerates dramatically.




Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: xstr8guy on September 20, 2014, 10:47:58 PM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
There are two popular difficulty estimators on line, and they both suck. One always underestimates, and one always overestimates. As the next adjustment gets closer, they converge. Someone needs to write a better one, and back-test it against the historical data.

Simple solution... just average the two yourself. And voila, there's your perfect estimate!


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Puppet on September 20, 2014, 10:53:41 PM
no estimate can ever be perfect, unless you have crystall ball, but it helps to understand how these sites make their prediction.
AFAIK, bitcoinwisdom extrapolates the growth over the past 1000 or so blocks, and thus implicitly assumes the past growth rate will continue, whereas blockexplorer tends to look only at the current network speed, and assumes no (further) growth.

In reality, the network tends to grow, thus bitcoinwisdom tends to be closer to the truth, but that growth is also beginning to slow down, so BW overestimates the next difficulty to some extend. Blockexplorer otoh, ignoring the historic reality of ever increasing network speed, tends to underestimate it, especially in the beginning of a difficulty period.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: philipma1957 on September 20, 2014, 11:12:13 PM
no estimate can ever be perfect, unless you have crystall ball, but it helps to understand how these sites make their prediction.
AFAIK, bitcoinwisdom extrapolates the growth over the past 1000 or so blocks, and thus implicitly assumes the past growth rate will continue, whereas blockexplorer tends to look only at the current network speed, and assumes no (further) growth.

In reality, the network tends to grow, thus bitcoinwisdom tends to be closer to the truth, but that growth is also beginning to slow down, so BW overestimates the next difficulty to some extend. Blockexplorer otoh, ignoring the historic reality of ever increasing network speed, tends to underestimate it, especially in the beginning of a difficulty period.

just about a perfect analysis.

take your choice blend and match either way you want


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: eoakland on September 21, 2014, 01:13:15 AM
In 5 days, the estimated difficulty increase has already gone from ~29,829,000,000 to ~35,259,000,000. At the current increasing rate of network hash power, in 5 more days, it's likely to hit 40,000,000,000.
This is really pushing the little guys out of business. Even with the most powerful and efficient miners, there is virtually no way to make a profit unless electricity is free and mining hardware is free. You'd expect with such extreme network hash power that BTC value should have skyrocketed to $1000 USD or more. But instead, it's remained somewhat steady around $500. And now, it's dropping closer to $400. How can this be profitable for anyone, even the huge mega farms?

I'm still doing pretty good. I am not sure where you get mining isn't profitable. Mine for the future, not today. If you're trying to pay bills with today's mining, you're going to lose. This has always been true. Think about the faith the guys in December 2011 had to have (me included) that were running farms of all sizes using gpus when the price was at $2.11 each. Electricity wasn't any cheaper and gpu's are 100X less efficient than Asics.

If you can't mine and hold, you need to get out.


~BCX~


easier said than done.  it's all relative i guess.  it's hard to mine in CA.  i know when i was mining "harder" i was paying damn near .30/kilowatt. 

FYI, you were correct about AUR coin.  not sure that you destroyed it like you claimed you were going to, but for the fact that it is a crap coin. 

cheers


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: fewcoins on September 22, 2014, 01:46:41 AM
Soon all these miners will exit! NOBODY said mining would be profitable


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: mikerbiker6 on September 22, 2014, 08:42:34 PM
we will just have to change from POW to DPOS
https://www.youtube.com/watch?v=_-TLA3j-ic4&feature=youtu.be&list=PL1zCD-urlm3iuJlUhq7Nwl5KuVXVShHKO (https://www.youtube.com/watch?v=_-TLA3j-ic4&feature=youtu.be&list=PL1zCD-urlm3iuJlUhq7Nwl5KuVXVShHKO)


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: jwcastle on September 24, 2014, 01:46:35 AM
Soon all these miners will exit! NOBODY said mining would be profitable

Just about EVERYONE has mentioned mining and profit in the same sentence.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Waramp22 on September 24, 2014, 06:40:32 AM
Soon all these miners will exit! NOBODY said mining would be profitable

Mining will never stop as bitcoin is self regulating. Its gotten a bit out of sync with the price lately because miners are very bullish or long on bitcoin and still expect the price to bounce back. We can only go so much higher before the increasing hashrate starts to slow because of miners realizing that it is currently not as profitable as they thought it was going to be. Pre-Orders are slow to arrive and thus the mining community is slow to react to declines in profitability.

Much like oil, if the demand/price is dropping over the long term they will slow the investment in their drilling programs. In this case, bitcoin mining.

The good part is, that if/when the increasing in hashrate starts to taper off the difficulty to mine a bitcoin will level off as well and profitability will start to return.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Puppet on September 24, 2014, 06:56:04 AM
Most of you seem to fail to understand that bitcoin mining is still quite profitable. Just not for you who pays retail prices for the hardware and consumer electricity prices.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: OrientA on September 24, 2014, 07:36:02 AM
Most of you seem to fail to understand that bitcoin mining is still quite profitable. Just not for you who pays retail prices for the hardware and consumer electricity prices.

The revenue is still higher than the electricity cost. But if you factor in the cost of rig, space and labor etc, then it is not profitable for some miners.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Puppet on September 24, 2014, 08:18:34 AM
The revenue is still higher than the electricity cost. But if you factor in the cost of rig, space and labor etc, then it is not profitable for some miners.

That its not profitable for some is irrelevant. As long as there are companies for whom it is profitable, difficulty will keep going up. And there is no way its not profitable for industrial mines with hardware at variable production cost, such as KnC's farm.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: bellgarath1 on September 24, 2014, 05:23:21 PM
One must keep reinvesting if you want to make a few bucks mining coin.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: taipo on September 25, 2014, 10:35:21 PM
39B - https://bitcoinwisdom.com/bitcoin/difficulty
45B - https://cryptanalys.is/difficulty/bitcoin_btc.php

So perhaps somewhere in the middle?


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: crazyearner on September 26, 2014, 01:14:33 AM
Everyone should team up and stop mining BTC and slow down then all hit it like a boss and get a big spike of rewards xD not much longer before 1TH miners out the window and soon the 10TH are going to be out and soon after that 100TH miners and game over and over and over again.  60GH back in the day was good making 2 to 3 BTC per day now you need like 50TH or more to even brake 1BTC a day . Ill continue to alt mine.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: mwizard on September 26, 2014, 04:32:20 AM
39B - https://bitcoinwisdom.com/bitcoin/difficulty
45B - https://cryptanalys.is/difficulty/bitcoin_btc.php

So perhaps somewhere in the middle?

As others have mentioned bitcoinwisdom is the one to use.  It looks at the last 2016 blocks solved and should be within about 4% of the actual average network hash rate over the last 2016 blocks 95% of the time.

I suspect cryptanalys.is badly in error for a few days after a difficulty change.

The problem with cryptanalys is that it either ignores, or does not understand, the statistic variation in the block solve time..  It basically says we are x fraction of the way through finding 2016 blocks and it took x time so we can now calculate the expected difficulty change.  But at the start of a new difficulty it is only using a few blocks in its calculation and the error is large.

For example after one day cryptanalys is only using about 144 blocks and the solve time calculation error and thus error in hash rate can be up to 20%.  The cryptanalys error declines as the next difficulty change approaches as there are more and more blocks included in the calculation until finally it is using 2016 blocks.

bitcoinwisdon appears to always use the last 2016 blocks so statistical variation is less important.

When the next difficulty change finally occurs both give the same result as both are using the solve time of the last 2016 blocks.

Mathematically there is a 10 minute block average solve time with a 10 minute variance (poisson distribution).  So the standard deviation percentage error in solve time is 100 / sqrt(number blocks).  This gives a standard deviation error of 8.3% for 144 blocks (1 day), 4.5% for 504 blocks, and 2.2% for 2016 blocks (difficulty change).  The variation will be within 2 Standard Deviations of the true value 95% of the time.  

Note - Six months ago, in the high growth rate days, you could have made a case for crptanalys,  as on the first day after a difficulty change it used the average of that day, rather than the bitcoinwisdon average for the past 2 weeks.  But with a lowering in hash rate growth this is less relevant.  The crptanalys error in the first days after a difficulty change is so large it swamps the effect of the data being slightly more up to date.

Feel free to improve or correct my understanding of how these sites work.









Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: taipo on September 26, 2014, 05:04:20 AM
https://cryptanalys.is/difficulty/bitcoin_btc.php now shows 34,709,951,920 with just 7 hours on since I made that post. So its predictions this early in the piece are as you say, quite off the mark.

Might have quite an interesting result this round I feel.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: DigitalPirateman on September 26, 2014, 05:14:36 AM
Kinda worried about it too but we all knew the difficulty will go this way just sooner then expected can't wait to see what it is next year.

As the price its buying time!!!!!!!!
https://i.imgur.com/J4UUv9a.jpg


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: skuser on September 26, 2014, 10:08:27 AM
https://cryptanalys.is/difficulty/bitcoin_btc.php now shows 34,709,951,920 with just 7 hours on since I made that post. So its predictions this early in the piece are as you say, quite off the mark.

Might have quite an interesting result this round I feel.

I started to parse predictions from all the sites I know about at http://nextdifficulty.com so you don't have to waste time switching between sites :D I will also track predictions in time so it'll be possible to see which are useful and which are not. If you know about other sites predicting difficulty let me know I'll add them too ;)


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: skuser on September 26, 2014, 10:21:51 AM
39B - https://bitcoinwisdom.com/bitcoin/difficulty
45B - https://cryptanalys.is/difficulty/bitcoin_btc.php

So perhaps somewhere in the middle?

As others have mentioned bitcoinwisdom is the one to use.  It looks at the last 2016 blocks solved and should be within about 4% of the actual average network hash rate over the last 2016 blocks 95% of the time.

I suspect cryptanalys.is badly in error for a few days after a difficulty change.

The problem with cryptanalys is that it either ignores, or does not understand, the statistic variation in the block solve time..  It basically says we are x fraction of the way through finding 2016 blocks and it took x time so we can now calculate the expected difficulty change.  But at the start of a new difficulty it is only using a few blocks in its calculation and the error is large.

For example after one day cryptanalys is only using about 144 blocks and the solve time calculation error and thus error in hash rate can be up to 20%.  The cryptanalys error declines as the next difficulty change approaches as there are more and more blocks included in the calculation until finally it is using 2016 blocks.

bitcoinwisdon appears to always use the last 2016 blocks so statistical variation is less important.

When the next difficulty change finally occurs both give the same result as both are using the solve time of the last 2016 blocks.

Mathematically there is a 10 minute block average solve time with a 10 minute variance (poisson distribution).  So the standard deviation percentage error in solve time is 100 / sqrt(number blocks).  This gives a standard deviation error of 8.3% for 144 blocks (1 day), 4.5% for 504 blocks, and 2.2% for 2016 blocks (difficulty change).  The variation will be within 2 Standard Deviations of the true value 95% of the time.  

Note - Six months ago, in the high growth rate days, you could have made a case for crptanalys,  as on the first day after a difficulty change it used the average of that day, rather than the bitcoinwisdon average for the past 2 weeks.  But with a lowering in hash rate growth this is less relevant.  The crptanalys error in the first days after a difficulty change is so large it swamps the effect of the data being slightly more up to date.

Feel free to improve or correct my understanding of how these sites work.



If bitcoinwisdom used 2016 blocks to predict difficulty then it should predict 0% difficulty growth everytime at the start of new period. I think they are using less amount of blocks but are incorrectly recalculating solved blocks speed with new difficulty, thats why they are way off at the period start.
The simple aproach is just take x last blocks, find average solving time and divide with time it should take. The problem is as you state with variance at lower blocks number and another problem is as I wrote most of the sites are lazy to recalculate blocks which have been solved in previous difficulty period with new difficulty level, which happens at the beginning of new period...


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: Oldminer on September 26, 2014, 10:45:22 AM
I'm still of the opinion BTC will eventually die & that it was simply a prototype.

Its old, out of date, and 14m coins is nowhere near enough not to mention probably millions have been 'lost'.

Looking forward to something (maybe a current coin?) to supersede it...


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: OrientA on September 26, 2014, 10:50:38 AM
I'm still of the opinion BTC will eventually die & that it was simply a prototype.

Its old, out of date, and 14m coins is nowhere near enough not to mention probably millions have been 'lost'.

Looking forward to something (maybe a current coin?) to supersede it...

I agree with that it is a prototype.

Even 1 m coins is enough because it is dividable.


Title: Re: OMG difficulty to hit 40,000,000,000 at current rate of increase
Post by: taipo on September 27, 2014, 02:41:40 AM
https://cryptanalys.is/difficulty/bitcoin_btc.php now shows 34,709,951,920 with just 7 hours on since I made that post. So its predictions this early in the piece are as you say, quite off the mark.

Might have quite an interesting result this round I feel.

I started to parse predictions from all the sites I know about at http://nextdifficulty.com so you don't have to waste time switching between sites :D I will also track predictions in time so it'll be possible to see which are useful and which are not. If you know about other sites predicting difficulty let me know I'll add them too ;)

Well done.

Chances are rising for a very low increase this round, barring a datacenter coming online in the next week of course......