我正在尝试使用R2jags
相机捕获站的栖息地协变量对整体物种丰富度的方差进行建模。但是,我不断收到错误:
"Error in jags.model(model.file, data = data, inits = init.values, n.chains = n.chains, :
RUNTIME ERROR:
Non-conforming parameters in function inprod"
我在以前的 JAGS 模型中使用了一个非常相似的函数(以查找物种丰富度(,所以我不确定为什么它现在不起作用......
我已经尝试以不同的方式格式化 inprod 函数中的协变量,作为数据框和矩阵,但无济于事。
变量规格:
J=length(ustations) #number of camera stations
NSite=Global.Model$BUGSoutput$sims.list$Nsite
NS=apply(NSite,2,function(x)c(mean(x)))
###What I think is causing the problem:
COV <- data.frame(as.numeric(station.cov$NDVI), as.numeric(station.cov$TRI), as.numeric(station.cov$dist2edge), as.numeric(station.cov$dogs), as.numeric(station.cov$Leopard_captures))
###but I have also tried:
COV <- cbind(station.cov$NDVI, station.cov$TRI, station.cov$dist2edge, station.cov$dogs, station.cov$Leopard_captures)
JAGS模型:
sink("Variance_model.txt")
cat("model {
# Priors
Y ~ dnorm(0,0.001) #Mean richness
X ~ dnorm(0,0.001) #Mean variance
for (a in 1:length(COV)){
U[a] ~ dnorm(0,0.001)} #Variance covariates
# Likelihood
for (i in 1:J) {
mu[i] <- Y #Hyper-parameter for station-specific all richness
NS[i] ~ dnorm(mu[i], tau[i]) #Likelihood
tau[i] <- (1/sigma2[i])
log(sigma2[i]) <- X + inprod(U,COV[i,])
}
}
", fill=TRUE)
sink()
var.data <- list(NS = NS,
COV = COV,
J=J)
捆绑数据:
# Inits function
var.inits <- function(){list(
Y =rnorm(1),
X =rnorm(1),
U =rnorm(length(COV)))}
# Parameters to estimate
var.params <- c("Y","X","U")
# MCMC settings
nc <- 3
ni <-20000
nb <- 10000
nthin <- 10
启动吉布斯采样器:
jags(data=var.data,
inits=var.inits,
parameters.to.save=var.params,
model.file="Variance_model.txt",
n.chains=nc,n.iter=ni,n.burnin=nb,n.thin=nthin)
最终,我得到错误:
Compiling model graph
Resolving undeclared variables
Allocating nodes
Deleting model
Error in jags.model(model.file, data = data, inits = init.values, n.chains = n.chains, :
RUNTIME ERROR:
Non-conforming parameters in function inprod
最后,我想计算栖息地协变量的平均值和 95% 可信区间 (BCI( 估计值,假设这些协变量会影响站点特定(点级(物种丰富度的方差。
任何帮助将不胜感激!
看起来您正在使用length
来生成U
的先验。在JAGS
中,此函数将返回节点数组中的元素数。在这种情况下,这将是行数乘以COV
列数。
相反,我会为您的data
列表提供一个标量,您提供给jags.model
.
var.data <- list(NS = NS,
COV = COV,
J=J,
ncov = ncol(COV)
)
在此之后,您可以修改JAGS
代码,在其中生成U
的先验。然后,该模型将变为:
sink("Variance_model.txt")
cat("model {
# Priors
Y ~ dnorm(0,0.001) #Mean richness
X ~ dnorm(0,0.001) #Mean variance
for (a in 1:ncov){ # THIS IS THE ONLY LINE OF CODE THAT I MODIFIED
U[a] ~ dnorm(0,0.001)} #Variance covariates
# Likelihood
for (i in 1:J) {
mu[i] <- Y #Hyper-parameter for station-specific all richness
NS[i] ~ dnorm(mu[i], tau[i]) #Likelihood
tau[i] <- (1/sigma2[i])
log(sigma2[i]) <- X + inprod(U,COV[i,])
}
}
", fill=TRUE)
sink()