Solved – Vector multiplication in BUGS and JAGS

bugsjags

In R, c(3,1,0) * c(2,0,1) == c(6,0,0). This is not dot product and it's not cross product. First, what is the name for this product, and second, does it work in WinBUGS, OpenBUGS and/or JAGS?

Best Answer

Unlike JAGS, WinBUGS and OpenBUGS does not do this form of vectorization; you have to write a loop, and compute each element 'by hand', as described above.

Related Solutions

Weibull Distribution – How to Parameterize a Weibull Distribution in JAGS / BUGS

Doing the algebra, we have $\lambda= (1/b)^a$ (by equating the constant term within the exponent): since $a=\nu$, this is consistent with $a (1/b)^{a} = \nu \lambda$. You're right that my answer elsewhere is wrong; feel free to edit it yourself if I don't get around to it sooner (at least the link is there to warn people) ...)

Solved – How to combine step(x) and dbern(p) in JAGS/WinBUGS

In JAGS, you can't reuse, in your case, y[j] as you sometimes can in WinBUGS. Instead, you create "new" data out of the data that you pass to JAGS in a data block at the top of the code (i.e., before the model step):

data {
  for (j in 1:N) {
    y[j] <- step(t.2[j] - t.1[j]) 
  }
}

You can then use y[j] on the left hand side of distributions in the model step:

model {
  for (j in 1:N) {
    ...
    y[j] ~ dbern(py)
    ...
  }
}

This can't be done in WinBUGS, however, as there's no data block; instead, you should just pass a precalculated variable y to WinBUGS.

Best Answer

Related Solutions

Weibull Distribution – How to Parameterize a Weibull Distribution in JAGS / BUGS

Solved – How to combine step(x) and dbern(p) in JAGS/WinBUGS

Related Question