function

LinearAlgebra.solveLower

Forward substitution through a lower triangular factor

Public declarations

Explicit source declarations; dimensions, modifications and defaults are shown as written, without evaluation.

Role	Name	Type	Dimensions / attributes / default
input	`factor`	`Real`	`[:, size(factor, 1)]`
input	`rhs`	`Real`	`[size(factor, 1), :]`
output	`solution`	`Real`	`[size(rhs, 1), size(rhs, 2)]`
output	`ok`	`Boolean`

Modelica declarations and implementation

Show parameters, interfaces and source

Parameters, inputs, outputs, defaults and equations from the source file.

function solveLower "Forward substitution through a lower triangular factor"
  input Real factor[:, size(factor, 1)];
  input Real rhs[size(factor, 1), :];
  output Real solution[size(rhs, 1), size(rhs, 2)];
  output Boolean ok;
protected
  Real value;
  Boolean pivotUsable;
algorithm
  solution := zeros(size(rhs, 1), size(rhs, 2));
  ok := true;
  for row in 1:size(factor, 1) loop
    pivotUsable := factor[row, row] > 0.0 and abs(factor[row, row]) < 1.0e30;
    ok := ok and pivotUsable;
    for column in 1:size(rhs, 2) loop
      value := rhs[row, column];
      for term in 1:(row - 1) loop
        value := value - factor[row, term] * solution[term, column];
      end for;
      solution[row, column] := if pivotUsable then value / factor[row, row] else 0.0;
    end for;
  end for;
end solveLower;