winbugs14 - How to code a matrix in WinBUGS? -

i trying code 2x2 matrix sigma 4 elements. not sure how code in winbugs. goal posterior p's, means , variances , create ellipse region covered 2 posterior p's. heres code below:

model{ #likelihood  for(j in 1 : nf){ p1[j, 1:2 ] ~ dmnorm(gamma[1:2], t[1:2 ,1:2])   (i in 1:2){     logit(p[j,i]) <- p1[j,i]     y[j,i] ~ dbin(p[j,i],n)       }   x_mu[j,1]<-p[j,1]-mean(p[,1])  x_mu[j,2]<-p[j,2]-mean(p[,2])  v1<-sd(p[,1])*sd(p[,1]) v2<-sd(p[,2])*sd(p[,2]) v12<-(inprod(x_mu[j,1],x_mu[j,2]))/(sd(p[,1])*sd(p[,2]))  sigma[1,1]<-v1 sigma[1,2]<-v12 sigma[2,1]<-v12 sigma[2,2]<-v2 sigmainv[1:2, 1:2] <- inverse(sigma[,])   t1[j,1]<-inprod(sigmainv[1,],x_mu[j,1])  t1[j,2]<-inprod(sigmainv[2,],x_mu[j,2])   ell[j,1]<-inprod(x_mu[j,1],t1[j,1]) ell[j,2]<-inprod(x_mu[j,2],t1[j,2])   }     #priors gamma[1:2] ~ dmnorm(mn[1:2],prec[1:2 ,1:2]) expit[1] <- exp(gamma[1])/(1+exp(gamma[1])) expit[2] <- exp(gamma[2])/(1+exp(gamma[2])) t[1:2 ,1:2] ~ dwish(r[1:2 ,1:2], 2) sigma2[1:2, 1:2]  <- inverse(t[,]) rho  <-  sigma2[1,2]/sqrt(sigma2[1,1]*sigma2[2,2]) }     # data  list(nf =20, mn=c(-0.69, -1.06), n=60,  prec = structure(.data = c(.001, 0,             0, .001),.dim = c(2, 2)),  r = structure(.data = c(.001, 0,          0, .001),.dim = c(2, 2)),  y= structure(.data=c(32,13,          32,12,          10,4,                       28,11,                           10,5,                          25,10,         4,1,        16,5,        28,10,        21,7,       19,9,      18,12,      31,12,       13,3,      10,4,      18,7,      3,2,     27,5,     8,1,      8,4),.dim = c(20, 2)) 

you have specify each element in turn. can use inverse function (rather solve) invert matrix.

model{   sigma[1,1]<-v1   sigma[1,2]<-v12   sigma[2,1]<-v21   sigma[2,2]<-v2   sigmainv[1:2, 1:2] <- inverse(sigma[,]) }