-The system has two main parts: this website which maintains a -searchable database of commodity prices, and an upload client, which -screenscrapes the commodity data from the Puzzle Pirates game client -and uploads it to the database. +The Market prices database is the main output +from YARRG. It offers a variety of enquiry options. -
-The lookup page gives access to the uploaded data. +Hopefully you will be able to work it without too much help, but this +documentation page contains information about the database website +which you may not be able to divine from the online user interface. -
-The current official version of YARRG for use as an upload -client can browsed here: - http://www.chiark.greenend.org.uk/~ijackson/ypp-sc-tools/master/ -See particularly the -YARRG README. +(An exception to this is if you select the `Update' option from the +`Trades for route' lookup; the list of (de)selected stalls is too long +to fit in a URL.) + +
-To install the client, install the `git' version control system -and the other dependencies listed in the `Installation requirements' -section of the README and then run: -
-git-clone http://www.chiark.greenend.org.uk/~ijackson/ypp-sc-tools/master/.git ypp-sc-tools -cd ypp-sc-tools -cd yarrg -make --this will download the code into the directory
ypp-sc-tools,
-and build the software.
+
+If you specify only one island or one archipelago, the site shows only
+arbitrage trades. If you want single-hop trades within an
+archipelago, you must enter the archipelago name twice.
-When new versions of the upload client are released, you can: +After getting the results, you can untick various trades individually, +and select `Update' to get a new plan. The unticked trades will be +excluded from the voyage plan (if any) and also from the totals. + +
+ +So you should specify your vessel capacity. You can enter things +like: +
+ +More formally:
-cd .../ypp-sc-tools
-git-pull
-cd yarrg
-make
+ capacity-string := [ first-term term* ]
+ term := ('+' | '-' | 'plus' | 'minus') (value+ | number'%')
+ value := mass | volume
+ | integer commodity-name-or-abbreviation
+ mass := number ('t' | 'kg')
+ volume := number ('kl' | 'l')
+ first-term := mass | volume | mass volume | volume mass
+ | ship-name-or-abbreviation
-to fetch the new version.
--YARRG is Free Software - you may share and modify it. See the -licences for details. +We model this by pretending that you expect to lose a fixed proportion +of your stock each league you sail. This expected loss does not +appear in the trade tables (although the distance does), but it does +affect the way the voyage trading plan optimiser chooses which trades +to do.
-Not only the client but also the webserver code is Free. The website
-code can be found in the same tree as above, in the web
-directory.
+Trades whose margin is less than the expected loss are never included
+in the suggested plan. For example, if you select 1% loss per league,
+and plan a voyage of 5 leagues, then any trade with a margin of less
+than 5.15% would be completely excluded (5.15% not 5% because the loss
+works like compound interest). Theoretically very profitable trades
+which are close to the expected break-even point because of the
+distance can also be rejected by the optimiser in favour of shorter
+distance trades with theoretically smaller margins, if it's not
+possible to do both.
-But in case we have made changes but not yet pushed them -(perhaps because we haven't done a release), and to make it easy for -anyone else who runs a copy of the website to provide everyone with -the source for their version, the website code itself lets you download -an up-to-date tarball of its -actually-running source code. +As a guide: you may expect to lose between 0.01% and 1% per league. +For example 0.1% would correspond to losing one fight to brigands (who +take 10% if they win) for every 100 leagues sailed.
-If you would like to run a (perhaps modified) copy of the YARRG -website it would be very easy for us to make our system send you -copies of updates submitted by users of the official YARRG client, in -the format expected by the code you'll be running. Please just ask -us. +You can enter the value in the box either as a percentage, or as a +fraction 1/divisor, eg 1/2000 is the same as 0.05%; in each +case it is taken as the loss for each league of the voyage. + +
-Email Ian Jackson ijackson (at) chiark.greenend.org.uk. Or talk to -any Fleet Officer or above of the crew Special Circumstances on the -Midnight Ocean. +The trading plan does not take into account accumulated profits from +each leg of the journey when applying the available capital +constraint. For example, if you specify a journey from A to B to C +and a capital limit of 10000 PoE, the trading plan will not tell you +to buy 1000 peas at A for 10 PoE each, sail them to B and sell all of +them for 20 PoE each, and then buy 2000 beans at B for 10 PoE each and +sail them to C to sell for 20 PoE each even if such a trade would in +fact be possible. In practice this is unlikely to be a problem! -<& footer, isdocs => 1 &> +<& footer &>