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Title: Large Transaction Displayed Fees
Post by: FullofSats on July 14, 2019, 04:41:13 PM

Hello. First time poster but long time lurker. This might be a noob question... By 'Large Transaction' I mean large number of inputs and outputs.

I'm looking into Wasabi CoinJoins on Blockchain explorers and there's something I don't understand: There is a slight difference between, on one hand the total btc input minus the total btc output, and on the other hand, the displayed miner fee.

For example in this transaction: https://blockchair.com/bitcoin/transaction/e9abc669f19439f7f738e26516106d74ddfc8ff761ce6e718dc9479392a05dfb

The displayed total input is 81.26491943, total output is 81.26462135, and miner's fee is 0.00029808. But if I click on the 'Raw transaction' button and add up all outputs from the JSON code, I get a total of 81.26462131. There's a 4 satoshis difference.

The transaction is displayed the same way on a few blockchain explorers. I also saw the same problem with other large transactions.

Where is the problem? Thanks.

Title: Re: Large Transaction Displayed Fees
Post by: achow101 on July 14, 2019, 07:12:01 PM

Are you sure that you are not making an error somewhere? I computed it myself and summing up the values from the JSON output given by blockchair is 81.26462135 as stated on the website. I get the same from my own node.

Title: Re: Large Transaction Displayed Fees
Post by: nc50lc on July 15, 2019, 03:10:19 AM

I copied the output values directly from the raw hex and got these:
.

84 x 0.10239329btc = 8.60103636btc
20 x 0.20473754btc = 4.0947508btc
6 x 0.40947508btc = 2.45685048btc
4 x 0.81895016btc = 3.27580064btc
3 x 1.63790032btc = 4.91370096btc
3 x 3.27580064btc = 9.82740192btc
2 x 6.55160128btc = 13.10320256btc
and more outputs of different value.

Now, copy this code and add all of them or paste the whole code here (scroll down) to add: http://v1.calculla.com/columnar_add (http://v1.calculla.com/columnar_add)

Code:

8.60103636
4.0947508
2.45685048
3.27580064
4.91370096
9.82740192
13.10320256
0.10268921
0.10185835
0.10238689
0.10284367
0.10242793
0.10196493
3.53096079
0.00206237
0.10196493
0.09094832
0.00489093
0.10298729
0.10208927
0.10382393
0.10402397
0.00105833
0.00465918
0.10208927
0.10353007
0.10196493
0.10208927
0.00115391
0.10208927
0.10213517
0.10208927
0.10400913
0.10252187
0.10185835
0.02236367
0.00073507
0.00199087
0.2118561
0.04666496
0.02228191
0.01954763
0.0907779
0.00384927
0.00314477
14.99773036
0.0011237
0.00273345
0.1434469
0.07885171
10.9170006
0.02734927
0.05574613
0.20853482
0.00102179
0.00611283
0.01339238
0.10363081
0.00228903
0.10382393
0.07111287
0.00253066
0.0023441
0.10189219
0.0099782
0.01764649
0.10181621
0.10196493
0.00235631
0.00087706
0.10347883
0.0747993
0.03097927
0.10208927
0.10735259
0.10423993
0.10670625
1.04619355
0.02834896

You'll get 81.26462135 which is the same as the displayed total output.

Title: Re: Large Transaction Displayed Fees
Post by: FullofSats on July 15, 2019, 02:49:09 PM

You were both right. The error lied in the softwares I was using: wolfram mathematica and libreoffice calc. It seems that for floating numbers greater than 1, the number of digits after decimal point is rounded to six, hence the difference. There is no problem for amounts lower than 1.

Thanks.

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Bitcoin => Bitcoin Technical Support => Topic started by: FullofSats on July 14, 2019, 04:41:13 PM