|Introduction: The Forecast family is about reading values off a forecast. This is useful for forecasting revenues that depend on a forecast of price, for example.|
- The simplest type of forecast is where prices change at even (for example annual) intervals. Fcst essentially does a lookup based on the date, against an evenly spread forecast.
- There is an optional variable in the Forecast family functions called úFcstSwitchOptú which allows you to specify whether you want a simple lookup or whether you want the function to interpolate if the date falls inbetween dates on the forecast.
- An evenly spaced forecast is specified in terms of a StartFcst date when the forecast starts, a FcstBase, which is the length of time in months between the values of the forecast, and FcstVals which are the forecast values themselves.
- Other functions in this family are variations on the basic theme. FcstGrow adds the ...Grow... feature and adds the ability to grow the value read off the forecast by one or a number of GrowthRates, effective from GrowthDates. Growth is applied to the forecast value at intervals specified by ¥ReviewMonths¥.
- FFcstStep and TFcstStep perform the forecasting job using an evenly spaced underlying forecast, but by adding the additional constraint that the value can only change in stepped amounts on certain dates. So the lookup first of all determines which step you are in, and then the Fcst value at the beginning of that step. This is useful in Real Estate applications where you want the prevailing rent that arose at the last Rent Review.
- TFcstStepMkt and FFcstStepMkt take the stepped forecast a stage further by allowing you to specify absolutely the first one or more steps, and then when you have not specified any more levels the function will read off the missing values off the forecast. Again, this has particular application in Real Estate.
- IdxFromTo is a different kind of forecasting mechanism, that"s in practise is actually very simple. It"s where you have a value that is linked to the value of and index and the value needs to stay in line with that index.