R/logpars2rrumpars.R

In CDM: Cognitive Diagnosis Modeling

## File Name: logpars2rrumpars.R
## File Version: 0.05


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# log parametrization to rum parametrization
#   pi * r1^(1-a1) * r2^(1-a2)
#=pi * r1 * r2 * (1/r1)^a1 * (1/r2)^a2
logpars2rrumpars <- function(delta_jj){
    v1 <- delta_jj
    N <- length(v1)
    v1 <- 1 / exp( delta_jj )
    v1[1] <- exp(sum( delta_jj))
    return(v1)
        }
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