BitShares Forum
Main => General Discussion => Topic started by: bitcrab on November 07, 2015, 05:24:09 am
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I don't know whether now I am the one that collated most BTS. but anyway I am sensitive to the feed price, as this is the key factor that trigger margin call.
(http://i13.tietuku.com/0970a64483f46285.png)
we always say that the price feed should be "accurate", not "fair", as it's not easy to define "fair", however, it seems we also need to check what "accurate" really mean.
take the BTS/CNY price as an example, when I write the price in yunbi is 0.0229CNY/BTS, in polo it is 0.00000886BTC/BTS and the settlement price is 0.0213CNY/BTS.
here the problem is that polo give a BTS/BTC price, so witness need to convert this price to BTS/CNY, I haven't check the script, but I believe many witnesses adopt the conversion path BTS/BTC->BTS/USD->BTS/CNY.
here the key point is what a USD/CNY rate should be adopted in the last step, I believe now many witnesses adopt the China official rate, about 6.35 , but when BTC is involved, this rate does not reflect the real market status.with such a rate when I write this post the BTC price is $382 in Coinbase but $401 in OKCoin.
the below USD/CNY rate is close to the fact in cryptocurrency world recently:
(http://i13.tietuku.com/641b702ad687351e.png)
so now let's come back to the question, in the CNY/BTS feed price example, what does "accurate" really mean? how to calcuate an "accurate" price?
in my view "accurate" means the feed price can be a good reference to the traders. so for a CNY/BTS trader, because of what explained above, the BTS/BTC->BTS/USD->BTS/CNY path does not generate an "accurate" price, a BTS/BTC->BTS/CNY path should be adoped instead, and the BTC/CNY rate should be got from the exchange inside China.
hope this problem can be putted on more attention and according action can be taken.
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+5%
I think this problem is very important to a BITCNY gateway.
The developer often don't have good oppotunity to get feeback from marketing especially from a gateway. In china the gateway brought a lot of liquidity to the BTS internal market in BTS1.0 and this is the reason why BitCNY was working very good in BTS1.0 and I think you all known this, I'm very appreciate all the thing what bitcrab did, doing and will do. he keep handle the BItCNY gateway in china in very hard condition and almost all BTS user in china was able to convert CNY<->BITCNY 24x7 with very very low fee. there're not much BTS users in china without this gateway.
this is not the first time Bitcrab post his idea in the forum to discuss, unfortunately there's always not much reply
Witness and the owner who provide a price feed App please pay attention to this.
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+5%
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+5%%%%%
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6.74
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I included the yunbi.com in the price feed of the witness node Harvey-xts.
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You describe the issue perfectly. I have several BTS/BTC markets and several BTC/USD markets .. the feed script takes these prices and the volumes for the corresponding markets and from this derives the cross products to get to all other prices .. pretty much like tri-asset arbitrage. Then, it derives a weightes (by volume) price. The Forex prices like USD/CNY are also taken into account. In the end, I would like to take all freely available markets into account and derive the cross-product prices.
Example:
USD / BTS = USD/BTC * BTC / BTS
but also
USD / BTS = CNY/BTC * USD/CNY * BTC/BTS
That sounded most fair to me as all exchanges get a fair share of the price. However, it also results in a wide standard deviation since many markets are involved.
How would you guys like to implement an ACCURATE price feed if you want to be decentralized/independent of just ONE exchange?