GenericDecompositionOperations<T>.BandLUDecompose Method

public override void BandLUDecompose(
	int m,
	int n,
	int kl,
	int ku,
	Span<T> ab,
	int ldab,
	Span<int> ipiv,
	out int info
)

Public Overrides Sub BandLUDecompose ( 
	m As Integer,
	n As Integer,
	kl As Integer,
	ku As Integer,
	ab As Span(Of T),
	ldab As Integer,
	ipiv As Span(Of Integer),
	<OutAttribute> ByRef info As Integer
)

public:
virtual void BandLUDecompose(
	int m, 
	int n, 
	int kl, 
	int ku, 
	Span<T> ab, 
	int ldab, 
	Span<int> ipiv, 
	[OutAttribute] int% info
) override

abstract BandLUDecompose : 
        m : int * 
        n : int * 
        kl : int * 
        ku : int * 
        ab : Span<'T> * 
        ldab : int * 
        ipiv : Span<int> * 
        info : int byref -> unit 
override BandLUDecompose : 
        m : int * 
        n : int * 
        kl : int * 
        ku : int * 
        ab : Span<'T> * 
        ldab : int * 
        ipiv : Span<int> * 
        info : int byref -> unit 

Parameters

m  Int32

            The number of rows of the matrix A.  M >= 0.
            

n  Int32

            The number of columns of the matrix A.  N >= 0.
            

kl  Int32

            The number of subdiagonals within the band of A.  KL >= 0.
            

ku  Int32

            The number of superdiagonals within the band of A.  KU >= 0.
            

ab  Span<T>

            AB is TComplex array, dimension (LDAB,N)
            On entry, the matrix A in band storage, in rows KL+1 to
            2*KL+KU+1; rows 1 to KL of the array need not be set.
            The j-th column of A is stored in the j-th column of the
            array AB as follows:
            AB(kl+ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl)
            On exit, details of the factorization: U is stored as an
            upper triangular band matrix with KL+KU superdiagonals in
            rows 1 to KL+KU+1, and the multipliers used during the
            factorization are stored in rows KL+KU+2 to 2*KL+KU+1.
            See below for further details.
            

ldab  Int32

            The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.
            

ipiv  Span<Int32>

            Dimension (min(M,N))
            The pivot indices; for 1 <= i <= min(M,N), row i of the
            matrix was interchanged with row IPIV(i).
            

info  Int32

            = 0: successful exit
            < 0: if INFO = -i, the i-th argument had an illegal value
            > 0: if INFO = +i, U(i,i) is exactly zero. The factorization
                 has been completed, but the factor U is exactly
                 singular, and division by zero will occur if it is used
                 to solve a system of equations.
            

            This is the blocked version of the algorithm, calling Level 3 BLAS.
            

Further Details:

            The band storage scheme is illustrated by the following example, when
            M = N = 6, KL = 2, KU = 1:
            On entry:                       On exit:
                *    *    *    +    +    +       *    *    *   u14  u25  u36
                *    *    +    +    +    +       *    *   u13  u24  u35  u46
                *   a12  a23  a34  a45  a56      *   u12  u23  u34  u45  u56
               a11  a22  a33  a44  a55  a66     u11  u22  u33  u44  u55  u66
               a21  a32  a43  a54  a65   *      m21  m32  m43  m54  m65   *
               a31  a42  a53  a64   *    *      m31  m42  m53  m64   *    *
            Array elements marked * are not used by the routine; elements marked
            + need not be set on entry, but are required by the routine to store
            elements of U because of fill-in resulting from the row interchanges.
            

Authors: Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver, NAG Ltd.

Date: November 2011

public override void BandLUDecompose(
	int m,
	int n,
	int kl,
	int ku,
	Span<Complex<T>> ab,
	int ldab,
	Span<int> ipiv,
	out int info
)

Public Overrides Sub BandLUDecompose ( 
	m As Integer,
	n As Integer,
	kl As Integer,
	ku As Integer,
	ab As Span(Of Complex(Of T)),
	ldab As Integer,
	ipiv As Span(Of Integer),
	<OutAttribute> ByRef info As Integer
)

public:
virtual void BandLUDecompose(
	int m, 
	int n, 
	int kl, 
	int ku, 
	Span<Complex<T>> ab, 
	int ldab, 
	Span<int> ipiv, 
	[OutAttribute] int% info
) override

abstract BandLUDecompose : 
        m : int * 
        n : int * 
        kl : int * 
        ku : int * 
        ab : Span<Complex<'T>> * 
        ldab : int * 
        ipiv : Span<int> * 
        info : int byref -> unit 
override BandLUDecompose : 
        m : int * 
        n : int * 
        kl : int * 
        ku : int * 
        ab : Span<Complex<'T>> * 
        ldab : int * 
        ipiv : Span<int> * 
        info : int byref -> unit 

Parameters

m  Int32

            The number of rows of the matrix A.  M >= 0.
            

n  Int32

            The number of columns of the matrix A.  N >= 0.
            

kl  Int32

            The number of subdiagonals within the band of A.  KL >= 0.
            

ku  Int32

            The number of superdiagonals within the band of A.  KU >= 0.
            

ab  Span<Complex<T>>

            AB is TComplex array, dimension (LDAB,N)
            On entry, the matrix A in band storage, in rows KL+1 to
            2*KL+KU+1; rows 1 to KL of the array need not be set.
            The j-th column of A is stored in the j-th column of the
            array AB as follows:
            AB(kl+ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl)
            On exit, details of the factorization: U is stored as an
            upper triangular band matrix with KL+KU superdiagonals in
            rows 1 to KL+KU+1, and the multipliers used during the
            factorization are stored in rows KL+KU+2 to 2*KL+KU+1.
            See below for further details.
            

ldab  Int32

            The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.
            

ipiv  Span<Int32>

            Dimension (min(M,N))
            The pivot indices; for 1 <= i <= min(M,N), row i of the
            matrix was interchanged with row IPIV(i).
            

info  Int32

            = 0: successful exit
            < 0: if INFO = -i, the i-th argument had an illegal value
            > 0: if INFO = +i, U(i,i) is exactly zero. The factorization
                 has been completed, but the factor U is exactly
                 singular, and division by zero will occur if it is used
                 to solve a system of equations.
            

            This is the blocked version of the algorithm, calling Level 3 BLAS.
            

Further Details:

            The band storage scheme is illustrated by the following example, when
            M = N = 6, KL = 2, KU = 1:
            On entry:                       On exit:
                *    *    *    +    +    +       *    *    *   u14  u25  u36
                *    *    +    +    +    +       *    *   u13  u24  u35  u46
                *   a12  a23  a34  a45  a56      *   u12  u23  u34  u45  u56
               a11  a22  a33  a44  a55  a66     u11  u22  u33  u44  u55  u66
               a21  a32  a43  a54  a65   *      m21  m32  m43  m54  m65   *
               a31  a42  a53  a64   *    *      m31  m42  m53  m64   *    *
            Array elements marked * are not used by the routine; elements marked
            + need not be set on entry, but are required by the routine to store
            elements of U because of fill-in resulting from the row interchanges.
            

Authors: Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver, NAG Ltd.

Date: November 2011

Reference