["function (params, inputs, indices, cached = NULL) ","{","    iind <- indices[, 1]","    jind <- indices[, 2]","    dp <- abs(inputs$pphase[iind] - inputs$pphase[jind])","    dw <- abs(inputs$plogwavelength[iind] - inputs$plogwavelength[jind])","    params[\"sigma2\"] * Matern(dp, range = params[\"rhop\"], nu = inputs$nu) * ","        Matern(dw, range = params[\"rhow\"], nu = inputs$nu)","}"]