Buying at a discount (bug causing extra shrapnelification!)

sl75

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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 16:11:46 GMT

Quote

Post by sl75 on Sept 29, 2015 16:11:46 GMT

I noticed in a couple of recent successful purchases at a discount that there appears to be a bug in the code handing it.

Specifically, it looks like it attempted to use all available funds in the MLIA to purchase units in the loan (as my available funds were the limiting factor, rather than the amount on offer or my buying limit). A few minutes later, it found there were still some funds left (a couple of orders of magnitude less - about 2% of the amount purchased), and attempted again, and a few minutes later had a further attempt, until the residual error fell below the minimum representable amount to AC's 20 decimals.

The residual amount in each case was about 98% of the original amount.

It suggests that something was applying a 1% adjustment in the wrong direction.

tonyr
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 18:48:52 GMT

Quote

Post by tonyr on Sept 29, 2015 18:48:52 GMT

Sept 29, 2015 16:11:46 GMT sl75 said:

I noticed in a couple of recent successful purchases at a discount that there appears to be a bug in the code handing it.

Specifically, it looks like it attempted to use all available funds in the MLIA to purchase units in the loan (as my available funds were the limiting factor, rather than the amount on offer or my buying limit). A few minutes later, it found there were still some funds left (a couple of orders of magnitude less - about 2% of the amount purchased), and attempted again, and a few minutes later had a further attempt, until the residual error fell below the minimum representable amount to AC's 20 decimals.

The residual amount in each case was about 98% of the original amount.

It suggests that something was applying a 1% adjustment in the wrong direction.

I'm not sure that this bug/feature is just limited to loans with a discount. I often put stuff up for sale and sometimes it goes cleanly, but sometimes it goes in a few waves, each being a couple of orders of magnitude less than the last as you observe. I regularly have pages of people buying less than £0.01 - well nobody in their right mind would want to buy that little (sell - yes please!) so in my mind there is some non-complete feature.

mikes1531
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 19:27:37 GMT

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Post by mikes1531 on Sept 29, 2015 19:27:37 GMT

Sept 29, 2015 18:48:52 GMT tonyr said:

Sept 29, 2015 16:11:46 GMT sl75 said:

I noticed in a couple of recent successful purchases at a discount that there appears to be a bug in the code handing it.

Specifically, it looks like it attempted to use all available funds in the MLIA to purchase units in the loan (as my available funds were the limiting factor, rather than the amount on offer or my buying limit). A few minutes later, it found there were still some funds left (a couple of orders of magnitude less - about 2% of the amount purchased), and attempted again, and a few minutes later had a further attempt, until the residual error fell below the minimum representable amount to AC's 20 decimals.

The residual amount in each case was about 98% of the original amount.

It suggests that something was applying a 1% adjustment in the wrong direction.

I'm not sure that this bug/feature is just limited to loans with a discount. I often put stuff up for sale and sometimes it goes cleanly, but sometimes it goes in a few waves, each being a couple of orders of magnitude less than the last as you observe. I regularly have pages of people buying less than £0.01 - well nobody in their right mind would want to buy that little (sell - yes please!) so in my mind there is some non-complete feature.

Could some/all of those micro-transactions be the result of GEIA/GBBA accounts putting the last bits of idle cash in lenders' accounts to work? There must be lots of those created every time a loan held in those accounts makes a repayment.

Ton ⓉⓞⓃ
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 19:39:14 GMT

Quote

Post by Ton ⓉⓞⓃ on Sept 29, 2015 19:39:14 GMT

Sept 29, 2015 18:48:52 GMT tonyr said:

Sept 29, 2015 16:11:46 GMT sl75 said:

I noticed in a couple of recent successful purchases at a discount that there appears to be a bug in the code handing it.

Specifically, it looks like it attempted to use all available funds in the MLIA to purchase units in the loan (as my available funds were the limiting factor, rather than the amount on offer or my buying limit). A few minutes later, it found there were still some funds left (a couple of orders of magnitude less - about 2% of the amount purchased), and attempted again, and a few minutes later had a further attempt, until the residual error fell below the minimum representable amount to AC's 20 decimals.

The residual amount in each case was about 98% of the original amount.

It suggests that something was applying a 1% adjustment in the wrong direction.

I'm not sure that this bug/feature is just limited to loans with a discount. I often put stuff up for sale and sometimes it goes cleanly, but sometimes it goes in a few waves, each being a couple of orders of magnitude less than the last as you observe. I regularly have pages of people buying less than £0.01 - well nobody in their right mind would want to buy that little (sell - yes please!) so in my mind there is some non-complete feature.

Today I bought a small amount of the MTF is it #104? To get to a round figure only to find that it split my buy order in exact half making two purchases to get to my total requirement. I thought there might be two selling at a 1% discount but on reading this perhaps not.

"Stupidity is a very specific cognitive failing. Crudely put, it occurs when you don’t have the right conceptual tools for the job. The result is an inability to make sense of what is happening and a resulting tendency to force phenomena into crude, distorting pigeonholes."260
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sqh
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 19:50:46 GMT bracknellboy likes this

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Post by sqh on Sept 29, 2015 19:50:46 GMT

I suspect chris has got his hands on a quantum computer. The system appears to have detected interference of the planck constant by a gravitational wave in Dorset.

29th Sep 2015 at 13:32 Sale of loan part 13417889 (new id 13426576) for 0.0000000000000000000300000000000000024000 GBP - fee 0 GBP, annualised rate 10, loan: Dorset Property Development Loan (120).

Ton ⓉⓞⓃ
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 19:57:45 GMT

Quote

Post by Ton ⓉⓞⓃ on Sept 29, 2015 19:57:45 GMT

Sept 29, 2015 19:50:46 GMT sqh said:

I suspect chris has got his hands on a quantum computer. The system appears to have detected interference of the planck constant by a gravitational wave in Dorset.

29th Sep 2015 at 13:32 Sale of loan part 13417889 (new id 13426576) for 0.0000000000000000000300000000000000024000 GBP - fee 0 GBP, annualised rate 10, loan: Dorset Property Development Loan (120).

Competition Time.

Who has a smaller transaction than sqh?

The Winner gets.... (You have to come up with a funny prize too.)

"Stupidity is a very specific cognitive failing. Crudely put, it occurs when you don’t have the right conceptual tools for the job. The result is an inability to make sense of what is happening and a resulting tendency to force phenomena into crude, distorting pigeonholes."260
My Holdings

oldnick

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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 20:05:35 GMT

Quote

Post by oldnick on Sept 29, 2015 20:05:35 GMT

Sept 29, 2015 19:50:46 GMT sqh said:

I suspect chris has got his hands on a quantum computer. The system appears to have detected interference of the planck constant by a gravitational wave in Dorset.

29th Sep 2015 at 13:32 Sale of loan part 13417889 (new id 13426576) for 0.0000000000000000000300000000000000024000 GBP - fee 0 GBP, annualised rate 10, loan: Dorset Property Development Loan (120).

Any boffins care to estimate how many atoms of an actual penny coin that represents? And the cost of electricity of registering and shifting this virtual wealth around for a day? And the cost of electricity of speculating on the above (for a day)? And the cost of electricity in reading this...ZZZZZZZ... .

jonah
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 20:25:26 GMT

Quote

Post by jonah on Sept 29, 2015 20:25:26 GMT

Sept 29, 2015 20:05:35 GMT oldnick said:

Sept 29, 2015 19:50:46 GMT sqh said:

I suspect chris has got his hands on a quantum computer. The system appears to have detected interference of the planck constant by a gravitational wave in Dorset.

29th Sep 2015 at 13:32 Sale of loan part 13417889 (new id 13426576) for 0.0000000000000000000300000000000000024000 GBP - fee 0 GBP, annualised rate 10, loan: Dorset Property Development Loan (120).

Any boffins care to estimate how many atoms of an actual penny coin that represents? And the cost of electricity of registering and shifting this virtual wealth around for a day? And the cost of electricity of speculating on the above (for a day)? And the cost of electricity in reading this...ZZZZZZZ... .

Or how long it would take that part to generate 1p in interest

oldnick

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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 20:33:54 GMT

Quote

Post by oldnick on Sept 29, 2015 20:33:54 GMT

Sept 29, 2015 20:25:26 GMT jonah said:

Sept 29, 2015 20:05:35 GMT oldnick said:

Any boffins care to estimate how many atoms of an actual penny coin that represents? And the cost of electricity of registering and shifting this virtual wealth around for a day? And the cost of electricity of speculating on the above (for a day)? And the cost of electricity in reading this...ZZZZZZZ... .

Or how long it would take that part to generate 1p in interest

If I take 1p to mean one post, and I will, then that 'interested' post was received in under 20 minutes.

jonah
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Buying at a discount (bug causing extra shrapnelification!) Sept 29, 2015 21:29:21 GMT

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Post by jonah on Sept 29, 2015 21:29:21 GMT

oldnick insert groan here.

So apparently 2.6 e 22 atoms in a penny (not worked that out myself, Google helps).

That part seems to be 3e-20 pence assuming I've not missed a zero and ignoring the even less significant digits.

That gives 780 atoms I think.

Been a while since I did any science, but that isn't much.

tonyr
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Buying at a discount (bug causing extra shrapnelification!) Sept 30, 2015 4:33:13 GMT

Quote

Post by tonyr on Sept 30, 2015 4:33:13 GMT

Sept 29, 2015 19:39:14 GMT Ton ⓉⓞⓃ said:

Sept 29, 2015 18:48:52 GMT tonyr said:

I'm not sure that this bug/feature is just limited to loans with a discount. I often put stuff up for sale and sometimes it goes cleanly, but sometimes it goes in a few waves, each being a couple of orders of magnitude less than the last as you observe. I regularly have pages of people buying less than £0.01 - well nobody in their right mind would want to buy that little (sell - yes please!) so in my mind there is some non-complete feature.

Today I bought a small amount of the MTF is it #104? To get to a round figure only to find that it split my buy order in exact half making two purchases to get to my total requirement. I thought there might be two selling at a 1% discount but on reading this perhaps not.

Good example. There's only one person selling at a discount (I do keep checking) so why on earth does it do this splitting?

sl75

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Buying at a discount (bug causing extra shrapnelification!) Sept 30, 2015 8:09:44 GMT

Quote

Post by sl75 on Sept 30, 2015 8:09:44 GMT

Just for completeness, the original series of transactions that demonstrated this as a bug to me:

15405196 2015-09-28 13:17:33.537193+01 settled Instant withdrawal from Quick Access Account (5) 5.642510203
15405197 2015-09-28 13:17:33.537193+01 settled Purchase loan part 13416669 (old id 13385532) for 14.7062499894883063445000000000000000000000 GBP with a 1% Discount (14.5591874895934232810550000000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -14.55918749
15405517 2015-09-28 13:25:47.82723+01 settled Instant withdrawal from Quick Access Account (5) 0.289727831
15405518 2015-09-28 13:25:47.82723+01 settled Purchase loan part 13416865 (old id 13416671) for 0.2926543747908172962500000000000000000000 GBP with a 1% Discount (0.2897278310429091232875000000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -0.289727831
15405715 2015-09-28 13:33:29.537822+01 settled Instant withdrawal from Quick Access Account (5) 0.005765584
15405716 2015-09-28 13:33:29.537822+01 settled Purchase loan part 13416974 (old id 13416866) for 0.0058238220583372642500000000000000000000 GBP with a 1% Discount (0.0057655838377538916075000000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -0.005765584
15405959 2015-09-28 13:37:07.31981+01 settled Instant withdrawal from Quick Access Account (5) 0.000114735
15405960 2015-09-28 13:37:07.31981+01 settled Purchase loan part 13417069 (old id 13416975) for 0.0001158940589609114630000000000000000000 GBP with a 1% Discount (0.0001147351183713023483700000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -0.000114735
15405989 2015-09-28 13:46:19.435466+01 settled Instant withdrawal from Quick Access Account (5) 2.28323E-06
15405990 2015-09-28 13:46:19.435466+01 settled Purchase loan part 13417075 (old id 13417070) for 0.0000023062917733221366000000000000000000 GBP with a 1% Discount (0.0000022832288555889152340000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -2.28323E-06
15406004 2015-09-28 13:50:55.011002+01 settled Instant withdrawal from Quick Access Account (5) 4.54363E-08
15406005 2015-09-28 13:50:55.011002+01 settled Purchase loan part 13417078 (old id 13417076) for 0.0000000458952062891058000000000000000000 GBP with a 1% Discount (0.0000000454362542262147420000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -4.54363E-08
15406014 2015-09-28 13:58:43.467619+01 settled Instant withdrawal from Quick Access Account (5) 9.04181E-10
15406015 2015-09-28 13:58:43.467619+01 settled Purchase loan part 13417084 (old id 13417079) for 0.0000000009133146051579000000000000000000 GBP with a 1% Discount (0.0000000009041814591063210000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -9.04181E-10
15406242 2015-09-28 14:02:28.974719+01 settled Instant withdrawal from Quick Access Account (5) 1.79932E-11
15406243 2015-09-28 14:02:28.974719+01 settled Purchase loan part 13417234 (old id 13417085) for 0.0000000000181749606390000000000000000000 GBP with a 1% Discount (0.0000000000179932110326100000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -1.79932E-11
15406327 2015-09-28 14:11:38.710866+01 settled Instant withdrawal from Quick Access Account (5) 3.58065E-13
15406328 2015-09-28 14:11:38.710866+01 settled Purchase loan part 13417262 (old id 13417235) for 0.0000000000003616817193000000000000000000 GBP with a 1% Discount (0.0000000000003580649021070000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -3.58065E-13
15406340 2015-09-28 14:17:17.629231+01 settled Instant withdrawal from Quick Access Account (5) 7.12549E-15
15406341 2015-09-28 14:17:17.629231+01 settled Purchase loan part 13417270 (old id 13417263) for 0.0000000000000071974683000000000000000000 GBP with a 1% Discount (0.0000000000000071254936170000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -7.12549E-15
15406349 2015-09-28 14:23:50.155206+01 settled Instant withdrawal from Quick Access Account (5) 1.418E-16
15406350 2015-09-28 14:23:50.155206+01 settled Purchase loan part 13417273 (old id 13417271) for 0.0000000000000001432332000000000000000000 GBP with a 1% Discount (0.0000000000000001418008680000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -1.418E-16
15406562 2015-09-28 14:26:37.975582+01 settled Instant withdrawal from Quick Access Account (5) 2.82E-18
15406563 2015-09-28 14:26:37.975582+01 settled Purchase loan part 13417401 (old id 13417274) for 0.0000000000000000028512000000000000000000 GBP with a 1% Discount (0.0000000000000000028226880000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -2.82E-18
15406579 2015-09-28 14:36:36.203138+01 settled Instant withdrawal from Quick Access Account (5) 6E-20
15406580 2015-09-28 14:36:36.203138+01 settled Purchase loan part 13417410 (old id 13417402) for 0.0000000000000000000594000000000000000000 GBP with a 1% Discount (0.0000000000000000000588060000000000000000 GBP paid) - annualised rate 10, loan: Midlands Trade Finance Provider Loan Tranche 4 (109) -6E-20

By adding up the purchases, I see that at the start of the sequence I had about £14.8548 of funds available, which would have been enough to have been allocated £15.0048 of the loan at face value (and indeed in this sequence that's the amount I ended up with)

The correct calculation would be to divide my available amount by 0.99 (or multiply by 1.0101010101... if that's easier) in order to determine the amount to allocate me (when multiplied by 0.99 to apply the discount that ends up equal to my available funds). Instead the system has allocated me an amount that was my available funds MULTIPLIED by 0.99. This then gets multiplied by 0.99 again to apply my discount, resulting in me spending exactly 98.01% of my available funds...

... a few minutes later the systems notices the remaining unspent 1.99% of the original funds, does the incorrect calculation on that again, and leaves 1.99% of 1.99% etc.

Why do chris and his team continue to make such fundamental errors, and release them to us untested? Have they even heard of unit testing?

chris
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Buying at a discount (bug causing extra shrapnelification!) Sept 30, 2015 8:32:25 GMT Jack Barlow, marek63, and 1 more like this

Quote

Post by chris on Sept 30, 2015 8:32:25 GMT

Sept 30, 2015 8:09:44 GMT sl75 said:

Why do chris and his team continue to make such fundamental errors, and release them to us untested? Have they even heard of unit testing?

Why the need for such a personal attack? Of course the team have heard of testing and unit testing, but such testing doesn't pick up every single edge case scenario. There was also a change in philosophy close to launch as to how the discount should be applied to the total investment being asked for and from what I can see in the information you've posted we've missed a check somewhere which rounds the transaction to the amount available. This could also relate to a more recent change post launch to the way the sales are enacted within the database.

If you don't like the platform, our approach, the speed of development (with a fraction of the resources of Fabulous Cabarets for example and have none of their balance synchronisation issues), etc. then don't use the platform. We're expanding the team, speed of development is likely to slow for a while now at least on the core platform, and we're working hard to improve our processes and procedures, but to our credit we've rewritten the entire aftermarket, all the investment accounts, and significantly extended the virtual banking system and thus far have had a couple of small bugs such as this one with all of the fundamentals working. This was no small undertaking, roughly analogous in terms of complexity and amount of work to writing a new platform from scratch.

Former CTO of one of the platforms posting in a personal capacity.

Bagman
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Buying at a discount (bug causing extra shrapnelification!) Sept 30, 2015 11:19:49 GMT Ton ⓉⓞⓃ and tonyr like this

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Post by Bagman on Sept 30, 2015 11:19:49 GMT

It looks like it is now fixed as I just picked up some Dental and Yorkshire leisure at a nice clean 5% discount all in one pop..

30th Sep 2015 at 11:53 Purchase loan part 13431058 (old id 12295645) for 7.2219730269429490779000000000000000052809 GBP with a 5% Discount (6.8608743755958016240050000000000000050169 GBP paid) - annualised rate 12, loan: ****dental (47)
£-6.86

30th Sep 2015 at 11:51 Purchase loan part 13430738 (old id 13226719) for 92.4752989297714443317300000000000000194223 GBP with a 5% Discount (87.8515339832828721151435000000000000184512 GBP paid) - annualised rate 13.5, loan: Yorkshire Leisure Business Loan (66)
£-87.85

chris
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Buying at a discount (bug causing extra shrapnelification!) Sept 30, 2015 16:33:33 GMT marek63 likes this

Quote

Post by chris on Sept 30, 2015 16:33:33 GMT

Sept 30, 2015 11:19:49 GMT Bagman said:

It looks like it is now fixed as I just picked up some Dental and Yorkshire leisure at a nice clean 5% discount all in one pop..

30th Sep 2015 at 11:53 Purchase loan part 13431058 (old id 12295645) for 7.2219730269429490779000000000000000052809 GBP with a 5% Discount (6.8608743755958016240050000000000000050169 GBP paid) - annualised rate 12, loan: ****dental (47)
£-6.86

30th Sep 2015 at 11:51 Purchase loan part 13430738 (old id 13226719) for 92.4752989297714443317300000000000000194223 GBP with a 5% Discount (87.8515339832828721151435000000000000184512 GBP paid) - annualised rate 13.5, loan: Yorkshire Leisure Business Loan (66)
£-87.85

It's not been changed so I suspect it's an edge case where available fund limit the amount bought. Haven't had a chance to look into it yet but will prioritise tomorrow morning.

Former CTO of one of the platforms posting in a personal capacity.