calcPosteriorRatio: Calculate change ratio of posterior concept value
In gregorbj/FSDM: Fuzzy Systems Dynamics Model

Description Usage Arguments Details Value

calcPosteriorRatio calculates the ratio of the new posterior concept value to the previous value due to a change in an anterior concept value

1	calcPosteriorRatio(Va, Ra, Vp, W)

`Va`	a numeric value in the interval (0, 100] identifying the value of the anterior concept.
`Ra`	a numeric value identifying the ratio of the anterior concept value and its previous value.
`Vp`	a numeric value in the interval (0, 100] identifying the value of the posterior concept.
`W`	a numeric value in the interval [-1, 1] identify the strength of the relationship between the anterior and posterior concepts in the relationship. Negative values denote inverse relationship.

This function calculates the ratio of change in the posterior concept value in a relationship due to the proportional change the anterior concept value in the relationship where proportional change is defined as (V' / V ) - 1. The algorithm assumes that the change to the remainder for the posterior concept is proportional to the change to the remainder for the anterior concept where the remainder is the difference between the value and the value limit in the direction of the change. Since the FSDM operates in the range of 0 to 100, the lower limit is 0 and the upper limit is 100. For example if the anterior concept changes from 20 to 40, the value limit is 100 and the remainder is 80. The change to the remainder is 20 divided by 80. The change to the remainder of the posterior concept is equal to the change to the remainder of the anterior concept multiplied by the relationship weight. For example if the weight is 0.5, then the change to the remainder of the posterior concept would be half of the change to the remainder of the anterior concept. Given this assumption, the proportional change to the posterior concept due to a change in an anterior concept can be calculated as a function of the anterior concept value prior to change, the posterior concept value, the proportional change in the anterior concept value, and the weight. The calculation of the change to the posterior concept differs depending on whether the proportional change to the anterior concept is positive or negative and whether the relationship weight is positive or negative. If either are 0, the result is 0.

A numeric value identifying the ratio of the updated posterior concept value to the starting posterior concept value due to the change in the anterior concept value.

gregorbj/FSDM documentation built on May 25, 2021, 11:41 p.m.