void bi::cov(const GammaPdf& q, M1 Sigma) {
/* pre-condition */
BI_ASSERT(Sigma.size1() == q.size());
BI_ASSERT(Sigma.size2() == q.size());
real alpha = q.shape();
real beta = q.scale();
real sigma = alpha*std::pow(beta, 2);
Sigma.clear();
set_elements(diagonal(Sigma), sigma);
}
void bi::cov(const InverseGammaPdf& q, M1 Sigma) {
/* pre-condition */
BI_ASSERT(Sigma.size1() == q.size());
BI_ASSERT(Sigma.size2() == q.size());
BI_ASSERT(q.shape() > 2.0);
real alpha = q.shape();
real beta = q.scale();
real sigma = std::pow(beta, 2)/(std::pow(alpha - 1.0, 2)*(alpha - 2.0));
Sigma.clear();
set_elements(diagonal(Sigma), sigma);
}
void bi::cov(const UniformPdf<V1>& q, M1 Sigma) {
/* pre-condition */
BI_ASSERT(Sigma.size1() == q.size());
BI_ASSERT(Sigma.size2() == q.size());
temp_host_vector<real>::type diff(q.size());
diff = q.upper();
sub_elements(diff, q.lower(), diff);
sq_elements(diff, diff);
Sigma.clear();
axpy(1.0/12.0, diff, diagonal(Sigma));
}
