Dakota Reference Manual: trend

| Dakota Reference Manual Version 6.15 Explore and Predict with Confidence

- Main Page
- Related Pages

All Pages
trend

Choose a trend function for a Gaussian process surrogate

## Specification

Alias: none

Argument(s): none

Default: reduced_quadratic

Child Keywords:

| Required/Optional | Description of Group | Dakota Keyword | Dakota Keyword Description
--- | --- | --- | --- | ---
| Required (Choose One) | Trend Order (Group 1) | constant | Constant trend function
linear | Use a linear polynomial or trend function
reduced_quadratic | Quadratic polynomials - main effects only

## Description

The only trend functions that are currently supported are polynomials.

The trend function is selected using the `trend` keyword, with options `constant`, `linear`, or `reduced_quadratic`. The `reduced_quadratic` trend function includes the main effects, but not mixed/interaction terms. The Surfpack GP (See surfpack) has the additional option of (a full) `quadratic`.