Computes gradient of Int(kappa_i(X, design1) . kappa_j(design2, X)) with respect to the first argument.
grad_W_kappa_ij2(design1, design2, theta, i1, i2, ct)matrix of size nrow(design1) x nrow(design2)
A vector representing a new point.
matrices of design points
lengthscales
index of the derivatives (WARNING: starts at 0)
Covariance type, 1 means Gaussian, 2 means Matern 3/2, 3 means Matern 5/2