LinearSolver
org.ejml.factory

Interface LinearSolver<T extends Matrix64F>

    • Method Detail

      • setA

        boolean setA(T A)

        Specifies the A matrix in the linear equation. A reference might be saved and it might also be modified depending on the implementation. If it is modified then modifiesA() will return true.

        If this value returns true that does not guarantee a valid solution was generated. This is because some decompositions don't detect singular matrices.

        Parameters:
        A - The 'A' matrix in the linear equation. Might be modified or save the reference.
        Returns:
        true if it can be processed.
      • quality

        double quality()

        Returns a very quick to compute measure of how singular the system is. This measure will be invariant to the scale of the matrix and always be positive, with larger values indicating it is less singular. If not supported by the solver then the runtime exception IllegalArgumentException is thrown. This is NOT the matrix's condition.

        How this function is implemented is not specified. One possible implementation is the following: In many decompositions a triangular matrix is extracted. The determinant of a triangular matrix is easily computed and once normalized to be scale invariant and its absolute value taken it will provide functionality described above.

        Returns:
        The quality of the linear system.
      • solve

        void solve(T B,         T X)

        Solves for X in the linear system, A*X=B.

        In some implementations 'B' and 'X' can be the same instance of a variable. Call modifiesB() to determine if 'B' is modified.

        Parameters:
        B - A matrix ℜ m × p. Might be modified.
        X - A matrix ℜ n × p, where the solution is written to. Modified.
      • invert

        void invert(T A_inv)
        Computes the inverse of of the 'A' matrix passed into setA(org.ejml.data.Matrix64F) and writes the results to the provided matrix. If 'A_inv' needs to be different from 'A' is implementation dependent.
        Parameters:
        A_inv - Where the inverted matrix saved. Modified.
      • modifiesA

        boolean modifiesA()
        Returns true if the passed in matrix to setA(org.ejml.data.Matrix64F) is modified.
        Returns:
        true if A is modified in setA().

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