SABER Blockchain Guide¶

At the source code level, SABER implements a ParametricBlockChain, an EnsembleBlockChain, a OuterBlockChain, and a HybridBlockChain which are all derived from the abstract SaberBlockChainBase base class. The base class sets up the base level functionality all derived block chains must implement.

The interface set up by the base class includes these public methods:

void randomize(oops::FieldSet4D &)
void multiply(oops::FieldSet4D &)
size_t ctlVecSize()
void multiplySqrt(const atlas::Field &, oops::FieldSet4D &, const size_t &)
void multiplySqrtAD(const oops::FieldSet4D &, atlas::Field &, const size_t &)
atlas::FunctionSpace & outerFunctionSpace()
oops::Variables & outerVariables()

From a user’s perspective, highly specific details of how the blockchains are implemented may not be as interesting and important as how to set up their desired B matrix model with SABER, but this section will provide some insight into the (sometimes intricate and esoteric) structure of a B matrix yaml configuration.

Static, ensemble, and hybrid are the standard _flavors_ of a B matrix model, and their general outline is described in Block chain specification.