fix ctcrw specification mean and sd

Author: bmcclintock

R/momentuHMM_utils.R

@@ -343,9 +343,11 @@ convertCTCRW <- function(distname,par,nbStates,data){
     dtm1 <- data$dt[1]
   }
   for(i in 1:nbStates){
-    mvnpar[i,] <- data[[paste0(distname,".x_tm1")]] + par[i,]^dtm1 * crw(data[[paste0(distname,".x_tm1")]],dt=data$dt)
-    mvnpar[nbStates+i,] <- data[[paste0(distname,".y_tm1")]] + par[i,]^dtm1 * crw(data[[paste0(distname,".y_tm1")]],dt=data$dt)
-    mvnpar[2*nbStates+i,] <- mvnpar[3*nbStates+i,] <- sqrt(par[nbStates+i,]^2*(par[i,]^(2*data$dt)-1)/(2*log(par[i,])))
+    beta <- -log(par[i,])
+    gamma <- exp(-beta*dtm1)
+    mvnpar[i,] <- data[[paste0(distname,".x_tm1")]] + data$dt * gamma * crw(data[[paste0(distname,".x_tm1")]],dt=data$dt)
+    mvnpar[nbStates+i,] <- data[[paste0(distname,".y_tm1")]] + data$dt * gamma * crw(data[[paste0(distname,".y_tm1")]],dt=data$dt)
+    mvnpar[2*nbStates+i,] <- mvnpar[3*nbStates+i,] <- sqrt(par[nbStates+i,]^2 * (1 - exp(-2 * beta * data$dt)) / (2 * beta))
   }
   return(mvnpar)
 }