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Matrix Stampers API

Package: gecko.core.circuit.matrix

MNA (Modified Nodal Analysis) matrix stamping strategies for circuit simulation. Each component type has a stamper that knows how to contribute to the system matrices.

Overview

The MNA equation is: A * x = b

  • A - admittance/conductance matrix
  • x - vector of unknowns (node voltages, branch currents)
  • b - source/excitation vector

Each component type stamps its contribution differently into A and b.

IMatrixStamper

Strategy interface for stamping component contributions into MNA matrices.

Methods

stampMatrixA

void stampMatrixA(double[][] a, int nodeX, int nodeY, int nodeZ,
                  double[] parameter, double dt);

Stamps the component's contribution into the A matrix (conductance/admittance).

Example (resistor R between nodes x and y):

  • a[x][x] += 1/R
  • a[y][y] += 1/R
  • a[x][y] -= 1/R
  • a[y][x] -= 1/R

Parameters:

Parameter Description
a The A matrix to stamp into
nodeX First node index
nodeY Second node index
nodeZ Auxiliary node index (for voltage sources, inductors)
parameter Component parameters array
dt Time step size

stampVectorB

void stampVectorB(double[] b, int nodeX, int nodeY, int nodeZ,
                  double[] parameter, double dt, double time,
                  double[] previousValues);

Stamps the component's contribution into the b vector (sources).

Example (current source I from node x to y):

  • b[x] -= I
  • b[y] += I

calculateCurrent

double calculateCurrent(double nodeVoltageX, double nodeVoltageY,
                        double[] parameter, double dt, double previousCurrent);

Calculates the component current after matrix solution.

getAdmittanceWeight

double getAdmittanceWeight(double parameterValue, double dt);

Gets the admittance weight factor (e.g., 1/R for resistor, C/dt for capacitor).

IStatefulStamper

Extension of IMatrixStamper for components that maintain internal state across time steps (e.g., inductors, capacitors with history).

StamperRegistry

Registry that maps circuit component types to their matrix stamper implementations. Implements the Strategy pattern for MNA matrix stamping.

StamperRegistry registry = StamperRegistry.createDefault();
IMatrixStamper stamper = registry.getStamper(CircuitTypCore.LK_R);
stamper.stampMatrixA(a, nodeX, nodeY, nodeZ, params, dt);

Methods

Method Returns Description
createDefault() StamperRegistry Factory with all standard stampers
getStamper(type) IMatrixStamper Get stamper for component type
register(type, stamper) void Register custom stamper
getSupportedTypes() Set<CircuitTypCore> All registered types
hasStamper(type) boolean Check if type is registered

Built-in Stamper Implementations

Class Component A-matrix Pattern
ResistorStamper Resistor 1/R conductance
CapacitorStamper Capacitor C/dt companion model
InductorStamper Inductor dt/L companion model
VoltageSourceStamper Voltage source Branch equation row
CurrentSourceStamper Current source b-vector only
DiodeStamper Diode Piecewise-linear model
MOSFETStamper MOSFET Switch + on-resistance
IGBTStamper IGBT Switch + saturation voltage
ThyristorStamper Thyristor Latching switch model
IdealSwitchStamper Ideal switch Zero/infinite impedance

SolverContext

Configuration context for the simulation solver, specifying which integration method to use.

Solver Constant Description
Backward Euler SOLVER_BE First-order implicit, unconditionally stable
Trapezoidal SOLVER_TRZ Second-order, may exhibit numerical oscillation
Gear-Shichman SOLVER_GS Multi-step, good for stiff circuits