Interpolation

YAC supports cell and point based fields. Examples for these are fluxes and temperatures respectively. Point based fields can be defined per corner, cell, or edge. In case of cells or edges, the user has to explicitly provide coordinates through the def_points-interface for the location of these points. Fields can be defined on points or on cells.

A target field can only be defined on a single point set. However, if supported by the interpolation, the source field can consist of multiple point sets (for example data values at the corners and edges of a cell).

If a mask is defined for a point set, it will be taken into account by the interpolations.

Interpolations in YAC are all in 2D on the sphere.

An interpolation consists of a Interpolation stack which in turn is comprised of one or more Interpolation methods (see Interpolation stack for a more detailed description).

If a field consists of multiple levels, whose interpolation is identical and have the same coupling frequency, they can all be exchanged at the same time with the same put/get-call. The same applies for different fields with the same coupling configuration. The number of 2D fields exchanged in a single put/get-call is configured by the "collection_size" parameter.

Interpolations are configured via the interface and/or read in from a configuration file.

In case the user calls put or get for a field for which no interpolation is configured in the configuration file, the calls will return immediately and will set the info argument accordinly.

In addition to the static field mask defined in The Definition Phase (see Definition of Masks), it also possible to provide a fractional mask along with the source field values in each exchange operation (see Data Exchange). This mask will be used in the interpolation and can be different for each exchange. For more details see Dynamic fractional masking.