Hi, All,
Please I have two questions in WinBUGS:
Question (1)
lambda is a parameter in my model which is defined as a quadratic function of
x; as follows:
lambda(x) = lambda0 + lambda1*x + lamda2*x^2
x is my data and each of the datapoint is positive. I would like lambda to be
positive for each value of x and also to have complex roots (that is no real
roots for the quadratic equation). I would also like lambda0 to be positive and
lambda2 to be negative.
Determining lambda reduces to estimating lambda0, lambda1 and lambda2.
My question is as follows: What prior distributions can I give to lambda0,
lambda1 and lambda2 and what other restrictions can I place on lambda0, lambda1
and lambda2 in order to obtain what I want above.
Question (2)
Do you know wether I can just put the differential equations describing my
model in WINBUGS code without solving for the analytical solutions? In
other words, can WINBUGS do the solving-equation things for me? Because
it's hard to get the analytical solutions sometimes, especially for the
nonlinear model.
If not is it possible to call a mathematical library from within WinBUGS?
Thanks in advance
--
Wilson Sama
Department of Public Health and Epidemiology, Swiss Tropical Institute
Socinstrasse 57, CH-4002, Basel, Switzerland
Email: [log in to unmask], [log in to unmask]
Tel: Institute: +41 61 284 8282
Mobile: +41 79 233 6748
Fax +41 61 271 7951
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