f01vc unpacks a real triangular matrix, stored in packed format in a one-dimensional array, to full format in a two-dimensional array. Packed storage format is described in [] in the F07 class Chapter Introduction.

Syntax

C#
public static void f01vc( string uplo, int n, double[] ap, double[,] a, out int info )

Visual Basic
Public Shared Sub f01vc ( _ uplo As String, _ n As Integer, _ ap As Double(), _ a As Double(,), _ <OutAttribute> ByRef info As Integer _ )

Visual C++
public: static void f01vc( String^ uplo, int n, array<double>^ ap, array<double,2>^ a, [OutAttribute] int% info )

F#
static member f01vc : uplo : string * n : int * ap : float[] * a : float[,] * info : int byref -> unit

Parameters

uplo

Type: System..::..String

On entry: specifies whether

A

is upper or lower triangular.

$uplo = "U"$: $A$ is upper triangular.
$uplo = "L"$: $A$ is lower triangular.

Constraint:

uplo = "U"

"L"

n: Type: System..::..Int32
On entry: $n$ , the order of the matrix $A$ .

Constraint: $n \geq 1$ .

ap

Type: array<System..::..Double>[]()[][]

An array of size [

n \times (n + 1) / 2

]

On entry: the

n

n

triangular matrix

A

, packed by columns.

More precisely,

if $uplo = "U"$ , the upper triangle of $A$ must be stored with element $A_{i j}$ in $ap [i + j (j - 1) / 2]$ for $i \leq j$ ;
if $uplo = "L"$ , the lower triangle of $A$ must be stored with element $A_{i j}$ in $ap [i + (2 n - j) (j - 1) / 2]$ for $i \geq j$ .

a

Type: array<System..::..Double,2>[,](,)[,][,]

An array of size [dim1, dim2]

Note: dim1 must satisfy the constraint:

dim1 \geq \max (1, n)

Note: the second dimension of the array a must be at least

n

On exit: the triangular matrix

A

If $uplo = "U"$ , $A$ is upper triangular and the elements of the array below the diagonal are not referenced.
If $uplo = "L"$ , $A$ is lower triangular and the elements of the array above the diagonal are not referenced.

info: Type: System..::..Int32%
On exit: $info = 0$ unless the method detects an error (see [Error Indicators and Warnings]).

Description

f01vc unpacks a real

n

n

triangular matrix

A

, stored in a one-dimensional array of length

n (n + 1) / 2

to conventional storage in a two-dimensional array. This method is intended for possible use in conjunction with methods from F06 class F07 class F08 class where some methods use triangular matrices stored in the packed form.

References

None.

Error Indicators and Warnings

Some error messages may refer to parameters that are dropped from this interface (LDA) In these cases, an error in another parameter has usually caused an incorrect value to be inferred.