flex Examples - LPIS

46 Flex Example Listingsrelation obtain seed for 'Lodgepole pine' from 'Skeena River'if the site is 'North Scotland'and the soil is not 'Peat'and the exposure is 'Moderate' .relation obtain seed for 'Lodgepole pine' from 'South Coastal'if the site is 'North Scotland'and the exposure is 'High' .% Note, the following relation must use "is" to set the value for "P" to% the given value. This is because "P" is a "logical" variable.% If instead of "P" we had "p", we would need to use "becomes" to assign% the value for the variant "p" to the given value.% Beware! If we used "p" and "is" this is interpreted as a check that the% value of "p" is the same as the given value.relation obtain seed for 'Lodgepole pine' from Pif the site is 'East Scotland'and if the soil is 'Peat' andthe peat is 'Unflushed peat' andthe elevation is 'Upper'then P is 'South Coastal'else P is { 'Southern Inland' or'Skeena River' }end if .relation obtain seed for 'Lodgepole pine' from Pif the site is 'West Scotland'and P is { 'South Coastal' or'Southern Inland' or'Skeena River' or'North Coastal' } .% in this program the provenances for seeds other than 'Sitka spruce' or% 'Lodgepole pine' are unspecifiedrelation obtain seed for Species from 'Unspecified Location...'if the Species is not { 'Sitka spruce' or 'Lodgepole pine' } .% The following section calculates the variance in the expected% yield class according to both the exposure of the location and the% provenance of the seedrelation compute TotalVariance for Provenanceif the exposure returns a variance of ExposureVarianceand Provenance returns a variance of ProvenanceVarianceand TotalVariance is ExposureVariance + ProvenanceVariance .relation 'Low' returns a variance of 2 .relation 'High' returns a variance of -2 .relation 'Southern Inland' returns a variance of -1 .relation 'Skeena River' returns a variance of -1 .relation 'North Coastal' returns a variance of -2 .A Guide to the Flex Expert System Toolkit