Configuration¶

The v2 code exposes configuration through model constructors and option structs rather than one monolithic ElmConfig. The effective configuration surface is the same: feature stack, solver options, backend, and seed.

Common fields¶

Field	Type	Default	Applies to	Notes
`numInputs`	`std::size_t`	required	all models	Input dimension
`numHiddenNodes`	`std::size_t`	required	`BatchElm`, `OsElm`, `OsCelm`	Additive hidden-node count
`hiddenNodesPerLayer`	`std::vector<std::size_t>`	required	`MlElm`, `HierarchicalOsElm`	One ELM-AE layer per entry
`ActivationFunction` / `ActivationKind`	enum	`kSigmoid`	additive maps and ELM-AE	`kSigmoid`, `kTanh`, `kRelu`
`Backend`	enum	`kCpu`	all models and feature maps	`kCpu` or `kGpu`
`seed`	`unsigned int`	`42u`	random maps and ELM-AE	Reproducible initialization
`ridgeAlpha`	`FloatT`	`1e-6`	batch ridge and ELM-AE	Positive regularization

Batch solver options¶

SolverOptions<FloatT> controls BatchRidgeSolver.

Option	Default	Values	Meaning
`ridgeAlpha`	`1e-6`	`> 0`	Regularizes `HᵀH + αI` or `HHᵀ + αI`
`path`	`kAuto`	`kAuto`, `kPrimal`, `kDual`	Selects primal when samples dominate hidden nodes and dual otherwise
`method`	`kCholesky`	`kCholesky`, `kHouseholderQr`	CPU factorization method; Cholesky is the stable default

Toggle path = kPrimal for many samples and few hidden nodes. Toggle path = kDual for many hidden nodes and few samples. Use kHouseholderQr only for research comparisons because Cholesky is faster on the regularized SPD system.

Online solver options¶

RlsOptions<FloatT> controls RlsSolver.

Option	Default	Values	Meaning
`regularization`	`1e-3`	`>= 0`	ReOS-ELM covariance regularization
`forgettingFactor`	`1`	`(0, 1]`	FOS-ELM forgetting; `1` is ordinary OS-ELM
`constraint`	`kNone`	`kNone`, `kClassDistance`	OS-CELM class-distance constraint
`constraintStrength`	`1e-2`	`>= 0`	Strength for class-distance constraint

An omitted extension must reduce to the baseline: forgettingFactor = 1, regularization = 0, and constraint = kNone are the off-switches.

RBF configuration¶

RbfMap is configured by:

Parameter	Default	Notes
`inputDim`	required	Input dimension
`numCenters`	required	Output dimension
`width`	`1.0`	Shared RBF width `σ`
`centerInit`	`kRandom`	`kRandom` or `kKMeans`
`seed`	`42`	Random center initialization

Demo configuration¶

DemoConfig controls the demo server.

Field	Default	Notes
`useGpu`	`false`	Enables GPU demo behavior when available
`staticPath`	`demo/ui`	Static web UI directory
`benchmarkPath`	`data/benchmarks/latest`	Benchmark JSON directory
`port`	`8888`	HTTP listen port

Drift stream configuration¶

DriftStream::Config controls synthetic non-stationary streams.

Field	Default	Notes
`inputDim`	`2`	Minimum is 2
`numClasses`	`2`	Binary drift stream
`streamLength`	`1000`	Samples before exhaustion
`driftPoint`	`500`	Sample where the regime changes
`seed`	`42`	Reproducible stream