Author Topic: Price Feed Review  (Read 7007 times)

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Online binggo

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Re: Price Feed Review
« Reply #90 on: June 02, 2019, 02:20:01 am »
As of this moment my feed for CNY is only off by 0.05 BTS from median price, that's less than $0.0034185, and that is just one witnesses' influence.

0.05bts?

your feed price: 0.4733cny*0.05bts=0.023665cny, i don't think it is a small influence, you have more 2% influence than fiat price.

Now the fiat bts price is: 0.485cny, can you explain how you got the 0.4733cny?

Later you give a feed price 0.4725cny?! please explain?

Quote
If they are off at certain times are they off enough to skew the median by a significant amount

This is what‘s your thoughts? please don't so childish.

Do you know what's the difference between the two USDT Price? why one is 0.48147? and why one is 0.47094?

Do you know what's the difference between the two BTC Price?

« Last Edit: June 02, 2019, 06:52:16 am by binggo »

Offline bitcrab

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Re: Price Feed Review
« Reply #91 on: June 02, 2019, 03:50:54 am »
median does not mean correct.

the median of a mess is also a mess.

it's not difficult for one user to find what a value is correct at a moment. only when every witness' feed price is good enough the median can be a dependable value.

Offline Thom

Re: Price Feed Review
« Reply #92 on: June 02, 2019, 08:06:02 pm »
median does not mean correct.

the median of a mess is also a mess.

it's not difficult for one user to find what a value is correct at a moment. only when every witness' feed price is good enough the median can be a dependable value.

Then one of us is definitely wrong, and I don't think it's me. Abit has commented as have others about the nature of the median price calculation. We use the median price, not an average for the very reason to exclude large influences by individual witnesses.

This leads me to think you're only trying to manipulate prices / trades through your pushing your perspective. It wouldn't be the first time you've done that.

@binggo, I didn't understand the calculation you made in which you claim my feed prices affects the median by more than 2%. I will study it more to try to make sense of it and will comment about that later.
Injustice anywhere is a threat to justice everywhere - MLK |  Verbaltech2 Witness Reports: https://bitsharestalk.org/index.php/topic,23902.0.html

Online binggo

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Re: Price Feed Review
« Reply #93 on: June 02, 2019, 11:46:13 pm »
@binggo, I didn't understand the calculation you made in which you claim my feed prices affects the median by more than 2%. I will study it more to try to make sense of it and will comment about that later.

Ok,correct the words,“you have more 2% influence price differential than fiat price.”


verbaltech2   0.4672   0.584   1.6   1.02   14 seconds ago
fox   0.4694   0.5633   1.6   1.01   8 minutes ago

BTC pirce
roelandp   0.4729   0.5675   1.6   1.02   3 minutes ago
xeldal   0.4734   0.5681   1.6   1.01   22 minutes ago
magicwallet.witness   0.4742   0.569   1.6   1.01   1 minute ago
xn-delegate   0.4756   0.5707   1.6   1.01   18 minutes ago
sahkan-bitshares   0.4758   0.571   1.6   1.02   19 minutes ago
blckchnd   0.4769   0.5723   1.6   1.02   44 minutes ago
bhuz   0.4776   0.5027   1.6   1.01   31 minutes ago
xman   0.4779   0.59   1.6   1.01   23 minutes ago
zapata42-witness   0.4781   0.5737   1.6   1.02   14 minutes ago
USDT pirce 6.90

witness.yao   0.4783   0.574   1.6   1.01   3 minutes ago
btspp-witness   0.4796   0.6149   1.6   1.01   9 minutes ago
delegate-zhaomu   0.4806   0.5768   1.6   1.01   8 minutes ago
in.abit   0.4807   0.6163   1.6   1.01   7 minutes ago
delegate.freedom   0.4809   0.6011   1.6   1.01   38 minutes ago
bangzi   0.4813   0.5776   1.6   1.01   13 minutes ago
zbbtsbp   0.4818   0.5353   1.6   1.01   52 minutes ago
clockwork   0.4829   0.5795   1.6   1.01   9 minutes ago
gdex-witness   0.483   0.637   1.6   1.01   1 minute ago
witness.hiblockchain   0.483   0.5796   1.6   1.01   13 minutes ago

so what?
« Last Edit: June 03, 2019, 06:36:54 am by binggo »

Offline alt

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Re: Price Feed Review
« Reply #94 on: June 03, 2019, 06:36:19 am »
unvoted delegate-zhaomu and magicwallet.witness

didn't get any response.
unvoted for verbatech2 and witness.yao.
will wait others response for another 24 hours.

Offline zhouxiaobao

Re: Price Feed Review
« Reply #95 on: June 03, 2019, 07:39:21 am »
     The price of DEX should be an important criterion to measure the accuracy of feed price.
     When Bitcny is not devalued, the feeding price should not be lower than the price of DEX. But in fact, this often happens, and that's why people complain.

Online binggo

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Re: Price Feed Review
« Reply #96 on: June 03, 2019, 11:07:39 am »
What's a ashamed feed price? can you feel that?

It's a shame for the BITasset and BTS holder.

If you can't find out what's wrong with your feed price, please don't feed it.

And this also said to some big voting Proxy, please don't act like a zombie.


Offline zhaomu

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Re: Price Feed Review
« Reply #97 on: June 03, 2019, 02:27:54 pm »
unvoted delegate-zhaomu and magicwallet.witness

didn't get any response.
unvoted for verbatech2 and witness.yao.
will wait others response for another 24 hours.

Greetings to Alt and the BTS community members,

Sorry for the late response to this situation and here is my explanation. On May 31st, bitcrab @ me in wechat group about the price feed issue and I responded immediately saying "I will check it" (see the figure below).



So I started to check my price feed script, which seems like the CNY to USD exchange rate caused the issue so I started to find more reliable API of currency exchange(I used the paid openexchangerates) and find if there is any logic bug can be fixed during the calculation of exchange rate. At the meanwhile, I was planning to add the premium between dex and external exchanges as a factor which is taken into consideration as a hotfix, to calculate the final price feed. However, when I first added the premium factor, I mistakenly messed up with its signs, but I found and fixed it immediately. So that's why there is a screenshot shows that the difference between my price feed and the median price feed reached 5%. In fact, this situation might not last for more than 10 minutes. You can see that bitcrab kindly reminded me about the issue at 13:47 and the screenshot about a 5% difference showed up around 14:00 when I am fixing. Finally, my price feed seemed like working well according to my observations later on that day(I am also constantly observing the price feed these days).

Since I thought that my price feed had been back to normal, I did not go to bitsharestalk to check if there was any new discussion about the price feed on the forum that day. And when I found this thread and prepared to respond, I found I cannot get the verification code to post unless *you know it* and due to the current network status(*you know it*), I failed a lot of times. Thus, I missed the in-time response to your question. I am extremely sorry for this and I promise that I will check the forum more frequently in the future. In fact, I really care about the price feed that I check it periodically and I also make quick responses to any changes decideded by the community consensus, e.g., MSSR.

This is my explanation about this event. I apologize for it again and I would be much appreciated if you can re-vote me again. Of course, any advice and suggestion from you and the community are thankful too. I will continue improving my price feed script. I hope we can make Bitshares much better.

Delegate-zhaomu

Offline zhouxiaobao

Re: Price Feed Review
« Reply #98 on: June 03, 2019, 03:24:11 pm »
      Feed price is too important for DEX. If the bitcny is at a premium and the price of the DEX does not fall, the feed price should not fall.
      The price of DEX is often suppressed by feed prices, but the rise of DEX does not push up feed  prices, which is why we are angry.

Offline abit

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Re: Price Feed Review
« Reply #99 on: June 03, 2019, 06:53:35 pm »
看了下这个平台就是FIAT USD,USDT和美元汇率就是1.0对吗?
USDT:法币USD 的历史价格,可以参考这个图 https://trade.kraken.com/markets/kraken/usdt/usd
这个是USD法币和USDT直接交易的交易对。
最近还比较稳,在 1.0 附近

Quote
可以认为人民币通过BTC交易换美元导致美元溢价了2.2个点,这样是可以解释内盘美元比人民币溢价2.2个点
按我的历史数据,USD:CNY 在 7.0到7.1x都出现过,并不是稳定在7.05,更不是6.9。
也就是说USD相对官方汇率的溢价在1.5-3范围波动。

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但是我当时是按美元计价得到内盘美元喂价低了超过2个点,人民币喂价差不多。
你看看bingo在我后面几分钟的截图,人民币计价 0.4728,按1美元7.05算是0.067美元。
有没有可能你们的脚本汇率转换逻辑有问题,把0.067美元的BTS按 6.9 转成人民币喂价 0.4627人民币,再按 7.05的汇率算成 0.0656美元了?
所以当时的实际情况是人民币和美元喂价都低了超过2个点。
binggo的图,你说的是这个吧:https://bitsharestalk.org/index.php?topic=28383.msg331008#msg331008

我看了下,那几个图是分别截的,第2/3个图明显时间戳差了十几分钟,第一个图看不到时间戳,不知道什么时候截的,感觉没法对比。
况且,第一个图是第三方行情站的图,行情站的数据采集是有延迟的,可信度不如直接从交易网站截图。

像下面我的截图这样,把所有网页窗口排在一起截的,都是一个时间点,就好算一点。

再说算法,你觉得你发帖的时候,人民币喂价差不多,这个帖子里
https://bitsharestalk.org/index.php?topic=28383.msg331007#msg331007
中间喂价 0.4640 你感觉是认可的?
你按 6.9 算的话usd喂价应该是 0.464/6.9 = 0.067

我当时的喂价是 cny 0.4637  usd 0.0652
也就是说 usd/cny = 0.4637/0.0652 = 7.11 比 6.9 差了近3个点,但逻辑是对得上的

Quote

@alt

为什么CNY:USD交易价格在7以上,而不是“官方”规定的6.9?因为“官方”汇率是被操纵的。而加密货币交易市场是自由的。

我的上次喂价:
Kraken BTC 报价 8550 美金
Bittrex BTC 报价 8549 美金
ZB BTC  报价 60241 RMB
AEX BTC 报价 60284 RMB

综合结果:
人民币:美金 约等于 7.05

最新报价截图


60300, 60202 / 8582, 8570 ~= 7.015, 7.036
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Online binggo

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Re: Price Feed Review
« Reply #100 on: June 03, 2019, 10:12:30 pm »
The exchange of USDT with CNY

https://c2c.huobi.co/en-us/trade/buy-usdt/
https://trans.zb.com/usdtqc
https://www.gate.io/trade/USDT_CNYX

aicoin这个是大多数国人在用的行情网站。
https://www.aicoin.net.cn/

实际就是国内只能以CNY转换为USDT入金,个别交易所可以以实际法币CNY直接入金。

从交易所取的价格也不能是实时成交价格,应当是深度加权中间价格
« Last Edit: June 03, 2019, 10:56:00 pm by binggo »

Offline Xeldal

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Re: Price Feed Review
« Reply #101 on: June 04, 2019, 12:57:54 pm »
Made some final changes to my script today.  I had CNY, USD, EUR, and BTC. properly feeding yesterday and removed my feeds on the rest of the assets temporarily until I had them reconfigured as well.  Which I've completed this morning.

I'm voted out at the moment.  Please consider re adding your votes.  Thanks. 



Offline abit

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Re: Price Feed Review
« Reply #102 on: June 04, 2019, 04:02:05 pm »
The exchange of USDT with CNY

https://c2c.huobi.co/en-us/trade/buy-usdt/
https://trans.zb.com/usdtqc
https://www.gate.io/trade/USDT_CNYX

aicoin这个是大多数国人在用的行情网站。
https://www.aicoin.net.cn/

实际就是国内只能以CNY转换为USDT入金,个别交易所可以以实际法币CNY直接入金。

从交易所取的价格也不能是实时成交价格,应当是深度加权中间价格
USDT现价约7.2 CNY

很多见证人的CNY喂价还行,但 USD 喂价是不对的,偏高。

进一步说,EUR和其他币种的喂价不知道差多远。

« Last Edit: June 04, 2019, 05:26:32 pm by abit »
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Online binggo

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Re: Price Feed Review
« Reply #103 on: June 05, 2019, 12:04:43 am »
USD的喂价其实也不高,因为还要看实际法币USD的进场是否流畅,还是通过USDT来转换,USDT的出场费用等。

每个地区的实际交易者才对实际的法币价格有深入的了解。

就好比现在跟后面这几位见证人解释不能采用官方汇率直喂BTC与USDT价格,他们很难理解,哪怕他们自己喂USD的价格也够呛能够了解清楚

USDT现价约7.2 CNY

很多见证人的CNY喂价还行,但 USD 喂价是不对的,偏高。

进一步说,EUR和其他币种的喂价不知道差多远。


Offline zhouxiaobao

Re: Price Feed Review
« Reply #104 on: June 05, 2019, 01:44:45 am »
        喂价应当是在本地购买bts所花费的法币数量。否则国际汇兑损失,交易手续费,等等,是很贵的,不计算进去,价格差就会很大。这就是为啥我们内盘投资者总觉得喂价低了,我们花的钱不止这个数啊!
       bitcny的喂价应当是“在中国购买一个bts需要的人民币法币数量”。
       bitusd的喂价应当是"在美国购买一个bts需要的美元法币数量"。
       这中间所有的手续费都应当算上。
       如果觉得难以采集数据,那就用最高价原则加上偏离顶,最高价最接近实际价格。
       mssr已经是1.01了,理论上充值费率不应当超过1%过多,现在快2%了,就是说喂价还是比实际价格低了一点。