FMP (version 1.4)

FMPMonotonicityCheck: Utility function for checking FMP monotonicity

Description

Utility function for checking whether candidate FMP coefficients yield a monotonically increasing polynomial.

Usage

FMPMonotonicityCheck(b, lower = -20, upper = 20)

Arguments

b

A vector of 8 polynomial coefficients ($b$) for $m(\theta)=b_0 + b_1 \theta + b_2 \theta^2 + b_3 \theta^3 + b_4 \theta^4 + b_5 \theta^5 + b_6 \theta^6 + b_7 \theta^7$.

lower, upper

Theta bounds for monotonicity check.

Value

minDeriv

Minimum value of the derivative for the polynomial.

Examples

## A set of candidate coefficients for an FMP model.
## These coefficients fail the test and thus
## should not be used with genFMPdata to generate
## item response data that are consistent with an 
## FMP model.
 b <- c(1.21, 1.87, -1.02, 0.18, 0.18, 0, 0, 0)
 FMPMonotonicityCheck(b)