Units > How do unit conversions work?

As mentioned in the topic titled Units, there are three basic typed of unit used by Resort Bistro; Weight, Volume, and Culinary.

Resort Bistro knows how to convert from any weight unit to any other weight unit. For instance the program can automatically convert from pounds to kilograms to ounces to grams, etc., for any ingredient or recipe without any user intervention. Similarly, the program can also automatically convert between any two volume units, say gallons to litres to fluid ounces, etc.

What the program can't do automatically is convert from say a bunch to grams. A bunch of something can weigh just about anything depending on what that something is (celery, parsley, etc.) and just what your idea of a bunch is.

When Resort Bistro cannot determine how to convert between two different units, the program displays the Unit Conversion Wizard to prompt you to supply a suitable unit conversion factor. The program then saves the conversion factor that you supplied and uses that conversion for that ingredient in the future.

Using 'Apples' as a typical example ingredient, you would normally use a unit like pounds when adding apples to a recipe. This is simple enough, but if you purchase your apples by the case, then you will enter a price per case to set up the cost for the apples. So, how does the program determine how much a pound of apples costs? It will need to be able to convert from case units to pounds units.

Say a case of apples weighs 20 pounds, then the conversion is easy, we take the cost per case and divide by 20 to get a cost per pound. But, we can't just assume that a case of just anything will give us 20 pounds of anything. Obviously, we need an 'item specific' unit conversion.

When you initially insert apples into a recipe, Resort Bistro will look up its table of stored unit conversions (for apples) looking for a way to convert from a known unit (case) to the new unit (pounds). If a conversion is not found, the program will prompt you to supply a conversion factor (How many pounds are there in a case of apples?) with the Unit Conversion Wizard. This conversion is saved by the program for future use.

Say, at a later time, you add 2 kilograms of apples to another recipe, you won't be asked for a unit conversion, because the program already knows how to convert from the purchase unit (case) to pounds, and the program already knows how to convert from pounds to kilograms as they are weight units, hence the price/kilogram can be calculated without any user intervention.

As you add more recipes to your Resort Bistro database, the program will build up a large list of unit conversions, stopping and asking for conversions when required.

When you first start work on a new database, the program will prompt you for unit conversions fairly regularly. As time passes and your database accumulates more and more unit conversions, it will eventually stop asking for them.

You can avoid being bugged for unit conversion when initially setting up a new database by enabling deferred unit conversions. See the topic titled 'What are 'deferred unit conversions'?' for more information.

NOTE: You cannot manually create unit conversions in the program. Resort Bistro will automatically prompt for a unit conversion the first time that the program needs that conversion to calculate a cost. One way to manually force the program to prompt for all required unit conversions is to perform a Batch Calculation. When performing a batch calculation, the program will recalculate the cost of every ingredient in every recipe and menu, and to do this, the program will require all the necessary unit conversion factors and will stop and ask for any unit conversions that it needs.