Package jline.lib.butools.mam

Class FluidTools

java.lang.Object
jline.lib.butools.mam.FluidTools
public final class FluidTools extends Object
Small matrix helpers shared by the fluid-queue ports (diagonal extraction, index-based submatrices, block assembly). Kept package-local to mirror the self-contained BUTools thirdparty style.

  • Method Summary

    Modifier and Type
    Method
    Description
    static Matrix
    blkdiag(Matrix A, Matrix B)
    Block-diagonal [[A 0];[0 B]].
    static Matrix
    block(Matrix A, Matrix B, Matrix C, Matrix D)
    2x2 block matrix [[A B];[C D]].
    static int[]
    concat(int[] a, int[] b)
    Concatenate two index arrays.
    static double[]
    diagArray(Matrix M)
    Diagonal of M as a double array.
    static Matrix
    diagFrom(double[] v)
    Diagonal matrix from a double array.
    static Matrix
    diagFrom(Matrix v)
    Diagonal matrix from a row/column vector.
    static Matrix[]
    expIntMoments(Matrix M, double L)
    {J0, J1} with J0=int_0^L expm(M u)du, J1=int_0^L u expm(M u)du via nilpotent augmentation.
    static Matrix
    hstack(Matrix A, Matrix B)
    [A B] side by side (handles zero-dimension blocks).
    static Matrix
    integExp(Matrix KA, double L)
    int_0^L expm(KA u) du, robust when KA has a zero eigenvalue (deflation).
    static Matrix[]
    integExp2(Matrix KA, Matrix KB, double L)
    {int_0^L expm(KA u)du, int_0^L expm(KB u)du}, applying deflation to the near-singular one.
    static Matrix
    linsolve(Matrix A, Matrix B)
    Solves A*X = B via partial-pivot LU (LAPACK-equivalent accuracy).
    static double
    minAbsEig(Matrix M)
    Minimum modulus of the eigenvalues of M.
    static Matrix
    nullvec(Matrix KA)
    Left null vector of KA via the CRPSolve algorithm (column, no generator check).
    static Object[]
    orderedSchur(Matrix A, double tol)
    Real Schur decomposition of A reordered so that the eigenvalues appear grouped as [zero real-part, negative real-part, positive real-part], the ordering used by MATLAB's ordschur in the multi-regime fluid solver.
    static Matrix[]
    orderedSchurRhp(Matrix A)
    Real Schur decomposition of A reordered so that eigenvalues with positive real part appear in the leading block, matching MATLAB's ordschur(U,T,'rhp').
    static int[]
    range(int n)
    0..n-1.
    static Matrix
    rowSums(Matrix M)
    Row vector of row-sums (each row summed across columns).
    static void
    setCols(Matrix dst, int[] cols, Matrix src)
    Assigns src (rows x |cols|) into the given columns of dst (all rows).
    static void
    setSub(Matrix dst, int[] ri, int[] ci, Matrix src)
    Assigns src into dst at rows ri, cols ci.
    static int[]
    shiftRange(int start, int n)
    start..start+n-1.
    static Matrix
    sub(Matrix M, int[] ri, int[] ci)
    Submatrix M(ri, ci) with index arrays (0-based).
    static Matrix
    triSylvester(Matrix A, Matrix B, Matrix C)
    Solves the Sylvester equation A*X - X*B = C where A (n x n) and B (m x m) are quasi-upper-triangular (real Schur form), via column-wise back-substitution (Bartels-Stewart), handling 1x1 and 2x2 diagonal blocks of B.
    static Matrix
    vec(Matrix M)
    Column-major reshape of M into a single column vector.
    static Matrix
    vstack(Matrix A, Matrix B)
    [A; B] stacked (handles zero-dimension blocks).

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • diagArray

      public static double[] diagArray(Matrix M)
      Diagonal of M as a double array.

    • diagFrom

      public static Matrix diagFrom(double[] v)
      Diagonal matrix from a double array.

    • diagFrom

      public static Matrix diagFrom(Matrix v)
      Diagonal matrix from a row/column vector.

    • sub

      public static Matrix sub(Matrix M, int[] ri, int[] ci)
      Submatrix M(ri, ci) with index arrays (0-based).

    • setSub

      public static void setSub(Matrix dst, int[] ri, int[] ci, Matrix src)
      Assigns src into dst at rows ri, cols ci.

    • setCols

      public static void setCols(Matrix dst, int[] cols, Matrix src)
      Assigns src (rows x |cols|) into the given columns of dst (all rows).

    • hstack

      public static Matrix hstack(Matrix A, Matrix B)
      [A B] side by side (handles zero-dimension blocks).

    • vstack

      public static Matrix vstack(Matrix A, Matrix B)
      [A; B] stacked (handles zero-dimension blocks).

    • block

      public static Matrix block(Matrix A, Matrix B, Matrix C, Matrix D)
      2x2 block matrix [[A B];[C D]].

    • blkdiag

      public static Matrix blkdiag(Matrix A, Matrix B)
      Block-diagonal [[A 0];[0 B]].

    • concat

      public static int[] concat(int[] a, int[] b)
      Concatenate two index arrays.

    • range

      public static int[] range(int n)
      0..n-1.

    • vec

      public static Matrix vec(Matrix M)
      Column-major reshape of M into a single column vector.

    • rowSums

      public static Matrix rowSums(Matrix M)
      Row vector of row-sums (each row summed across columns).

    • nullvec

      public static Matrix nullvec(Matrix KA)
      Left null vector of KA via the CRPSolve algorithm (column, no generator check).

    • minAbsEig

      public static double minAbsEig(Matrix M)
      Minimum modulus of the eigenvalues of M.

    • integExp

      public static Matrix integExp(Matrix KA, double L)
      int_0^L expm(KA u) du, robust when KA has a zero eigenvalue (deflation).

    • integExp2

      public static Matrix[] integExp2(Matrix KA, Matrix KB, double L)
      {int_0^L expm(KA u)du, int_0^L expm(KB u)du}, applying deflation to the near-singular one.

    • expIntMoments

      public static Matrix[] expIntMoments(Matrix M, double L)
      {J0, J1} with J0=int_0^L expm(M u)du, J1=int_0^L u expm(M u)du via nilpotent augmentation.

    • shiftRange

      public static int[] shiftRange(int start, int n)
      start..start+n-1.

    • orderedSchur

      public static Object[] orderedSchur(Matrix A, double tol)
      Real Schur decomposition of A reordered so that the eigenvalues appear grouped as [zero real-part, negative real-part, positive real-part], the ordering used by MATLAB's ordschur in the multi-regime fluid solver. Returns {Z, T, int[]{zeroeig, negeig, poseig}} with Z orthogonal, T quasi-upper-triangular and Z'*A*Z = T.

    • orderedSchurRhp

      public static Matrix[] orderedSchurRhp(Matrix A)
      Real Schur decomposition of A reordered so that eigenvalues with positive real part appear in the leading block, matching MATLAB's ordschur(U,T,'rhp'). Returns {Z, T} with Z orthogonal, T quasi-upper-triangular and Z'*A*Z = T.

    • linsolve

      public static Matrix linsolve(Matrix A, Matrix B)
      Solves A*X = B via partial-pivot LU (LAPACK-equivalent accuracy).

    • triSylvester

      public static Matrix triSylvester(Matrix A, Matrix B, Matrix C)
      Solves the Sylvester equation A*X - X*B = C where A (n x n) and B (m x m) are quasi-upper-triangular (real Schur form), via column-wise back-substitution (Bartels-Stewart), handling 1x1 and 2x2 diagonal blocks of B. Accurate even when A/B are large.