NAG C Library Function Document

nag_superlu_matrix_norm (f11mlc)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:    $\mathbf{norm}$ – Nag_NormTypeInput

On entry: specifies the value to be returned in anorm.

$\mathbf{norm}=\mathrm{Nag\_RealOneNorm}$

The $1$-norm ${‖A‖}_1$ of the matrix is computed, that is ${\displaystyle \underset{1\le j\le n}{\max }}{\displaystyle \sum _{i=1}^n}\left|A_{ij}\right|$.

$\mathbf{norm}=\mathrm{Nag\_RealInfNorm}$

The $\infty$-norm ${‖A‖}_{\infty }$ of the matrix is computed, that is ${\displaystyle \underset{1\le i\le n}{\max }}{\displaystyle \sum _{j=1}^n}\left|A_{ij}\right|$.

$\mathbf{norm}=\mathrm{Nag\_RealMaxNorm}$

The value ${\displaystyle \underset{1\le i,j\le n}{\max }}\left|A_{ij}\right|$ (not a norm).

Constraint: $\mathbf{norm}=\mathrm{Nag\_RealOneNorm}$, $\mathrm{Nag\_RealInfNorm}$ or $\mathrm{Nag\_RealMaxNorm}$.

2:    $\mathbf{anorm}$ – double *Output

On exit: the computed quantity relating the matrix.

3:    $\mathbf{n}$ – IntegerInput

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

Constraint: $\mathbf{n}\ge 0$.

4:    $\mathbf{icolzp}\left[\mathit{dim}\right]$ – const IntegerInput

Note: the dimension, dim, of the array icolzp must be at least $\mathbf{n}+1$.

On entry: $\mathbf{icolzp}\left[i-1\right]$ contains the index in $A$ of the start of a new column. See Section 2.1.3 in the f11 Chapter Introduction.

5:    $\mathbf{irowix}\left[\mathit{dim}\right]$ – const IntegerInput

Note: the dimension, dim, of the array irowix must be at least $\mathbf{icolzp}\left[\mathbf{n}\right]-1$, the number of nonzeros of the sparse matrix $A$.

On entry: the row index array of sparse matrix $A$.

6:    $\mathbf{a}\left[\mathit{dim}\right]$ – const doubleInput

Note: the dimension, dim, of the array a must be at least $\mathbf{icolzp}\left[\mathbf{n}\right]-1$, the number of nonzeros of the sparse matrix $A$.

On entry: the array of nonzero values in the sparse matrix $A$.

7:    $\mathbf{fail}$ – NagError *Input/Output

The NAG error argument (see Section 3.7 in How to Use the NAG Library and its Documentation).

6

Error Indicators and Warnings

NE_ALLOC_FAIL

Dynamic memory allocation failed.
See Section 2.3.1.2 in How to Use the NAG Library and its Documentation for further information.

NE_BAD_PARAM

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.

NE_INT

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{n}\ge 0$.

NE_INTERNAL_ERROR

An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
See Section 2.7.6 in How to Use the NAG Library and its Documentation for further information.

NE_NO_LICENCE

Your licence key may have expired or may not have been installed correctly.
See Section 2.7.5 in How to Use the NAG Library and its Documentation for further information.

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Accuracy

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Parallelism and Performance

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Further Comments

10

Example

10.1

Program Text

Program Text (f11mlce.c)

10.2

Program Data

Program Data (f11mlce.d)

10.3

Program Results

Program Results (f11mlce.r)