Topic: Exposure calculation

My only advice would be to play around on a spreadsheet first. That way the logic can be understood first, then the coding second.

Hope this helps,
Brendan

For single selections I use this:

for (index = ladder.LowestInterestingPriceIndex; index <= ladder.HighestInterestingPriceIndex; index++)
{
	layMatchedStake += ladder.Prices[index].MatchedLays;
	layMatchedProfit += ladder.Prices[index].MatchedLays * (ladder.Prices[index].Odds - 1);
	layExposure -= ladder.Prices[index].UnmatchedLays * (ladder.Prices[index].Odds - 1);

	backMatchedStake += ladder.Prices[index].MatchedBacks;
	backMatchedProfit += ladder.Prices[index].MatchedBacks * (ladder.Prices[index].Odds - 1);
	backExposure -= ladder.Prices[index].UnmatchedBacks;
}

netStakes = layMatchedStake - backMatchedStake;
netProfit = Math.Round(backMatchedProfit - layMatchedProfit, 2);

bestCase = Math.Max(netStakes, netProfit);
worstCase = Math.Min(netStakes, netProfit);

I'm looping across my ladder where I have cuimulative bet records, but the logic should be the same if you are doing a list of MUBets.

Should be relatively easy to extend for multiple selections.

Ooops see I missed a bit

layExposureNet = netProfit + layExposure;
backExposureNet = netStakes + backExposure;
exposure = Math.Min(layExposureNet, backExposureNet);

Thanks guys, an excellent example of why I love this forum!

BTW PeteB, I understand your code but I haven't come across the idea of a "price ladder" before. What's the idea behind it? I keep track of bets using a List<MUBet>, does using a ladder make anything easier? Is there some golden botting nugget of goodness about to be revealed?!

It's just another way of viewing the market - several of the big tools support it - have a look at the videos on http://www.racingtraders.com/ for an example. A vertical column of prices from 1.01 to 1000, and the market lays on the left and backs on the right. And then your lays appear in another column on the left, and your backs on the right.

I find this the most intuitive interface to trade on manually (I use the Gruss one) - and so I based my code the same way - just makes it easier for me to understand as I write it. Not sure it gives any programming advantage - for example if I get a price improvement I have to then split the matched bet across prices when I update my cumulative records on the ladder - I'm starting to think this is a pain. With lots of bets, then there might be less processing of the cumulative records than processing the raw list of bets - but I think I would have to re-process the raw list of bets after a reduction factor anyway - so maybe I will scrap this and just store a list of MUBets!

Yeah, I guess I could scrape it, but I was really after the exposure for just the market I'm currently 'looking' at. I assume the scrape call will return the exposure for all markets that I have bets on ie. for markets that haven't settled, yet even though I'm looking at the next race...if that makes sense?!