<p>
-So you should specify your vessel capacity. Currently you must
-specify the actual mass and volume, as two numbers each with units.
-The system understands the units t (tonnes), kg, l and kl
-(kilolitres). There should be a space between the two limits, and no
-space before the unit.
+So you should specify your vessel capacity. You can enter things
+like:
+<dl>
+<dt>sloop
+<dd>The capacity of a sloop, leaving no allowance for rum and shot
+<dt>wb - 1%
+<dd>The capacity of a war brig minus 1%
+<dt>20t 13kl
+<dd>13 tonnes (13,000kg), 20 kilolitres (20,000l)
+<dt>sloop - 100l 100kg
+<dd>The capacity of a sloop minus 100l, minus 100kg
+<dt>2t plus 500kg minus 200kg
+<dd>2300kg, with no limit on volume
+</dl>
+Evaluation is strictly from left to right.
+
+<p>
+
+Formally, the capacity is a list of terms, all but the first preceded
+by one of <kbd>-</kbd>, <kbd>minus</kbd>, <kbd>+</kbd>,
+<kbd>plus</kbd>. Each term may specify a mass and/or a volume
+(separated by a space), as a number followed (without an intervening
+space) by a unit (<kbd>t</kbd>, <kbd>kg</kbd>, <kbd>kl</kbd> or
+<kbd>l</kbd>). Alternatively each term except the first may specify a
+percentage, which is applied as a percentage change to the answer from
+all the preceding terms. The first term may be a ship name or
+abbrevation instead. If the first term specifies only one of mass or
+volume, all the subsequent terms may only adjust that same value.
<h3>Expected losses</h3>
<p>
-Trades whose margin is less than the expected loss are never selected.
-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.
+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.
<p>
~yarrgweb / ypp-sc-tools.db-test.git / blobdiff