Corlan bridge club > Probabilities calculator > The problem

The probability calculator is used by entering information known at a certain stage during the game and it produces probabilities of cards and lengthes and also example distributions.

The calculator can be used in two ways:

• with the online form
• using an URL schema, which is described in this page; a very quick, but hard, introduction could be just to look at this example game; for full disclosure, read on.

Information used in calculations The information used in calculations, for any or all hands, may consist in:

• range of honor points in the hand (minimum and maximum of honor points, perhaps known from previous bids)
• range of lengths of any suit (minimum and maximum number of cards in any or each suit, also likely known from previous bids)
• actual cards, known because they are in the player's hand, shown by the dummy, already played or (rarely) known from bids.

Building and URL. The URL specification of a problem consists of http://bridge.corlan.net:20209 followed by four slash-separated hand specifications.

The simplest hand specification is empty. For example:
http://bridge.corlan.net:20209///// will specify that we know nothing about the hand of any player, so all probabilities will be identical in all hands. The order of the players' hands in the URL is N, S, E, W.

Honor points range. In order to specify honor points range, simply put something like '13-19' in the correct place. For example, http://bridge.corlan.net:20209/13-19//// will say that north has 13-19 HP and we know nothing of the rest, http://bridge.corlan.net:20209//13-19/// will say that south has 13-19 points, http://bridge.corlan.net:20209///13-19// will say that east has 13-19 points and http://bridge.corlan.net:20209////13-19/ will say that player west has 13-19 points.

Short form. From this point we'll drop the http://bridge.corlan.net:20209 for brevity. So, 13-19 HP in the hand of east are written ///13-19//

Suit (color) lengths. Suit lengths are specified in four ';' separated fields, for spades, hearts, diamonds and clubs respectively. For example, to say that south has 13-19 honor points and at least 5 spades (from 5 to 13 that is), say: //13-19;5-13;;;///; to say that south has 5 to 13 hearts, say: //13-19;;5-13;;///;

Known cards in each hand. If you follow the suit length with a comma (or just put a comma when the suit length is not present) you can enter after the comma known cards of that suit in that hand. For example: //13-19;;5-13,K93;;/// means we know that player south has 13-19 honor points, 5-13 hearts and among them at the king, the 9 and the 3. Use 'T' for the ten. For example: //13-19;;AT6532;;/// means that south has 13-19 honor points and at least the ace, the 10, and 6, 5, 3 and 2.

Why use the URL method. Because it is faster, because you want to make a link to a simulation problem from a web page of yours, or because you want to download a large number of solutions using a tool such as wget. Have a look at the source code of this page for how to make links to simulations from web pages.