### ML_DLANGE – Computes one of the matrix norms of a general matrix

Block SymbolLicensing group: STANDARD

Function Description

The output references yA and yWORK are always set to the corresponding input references uA
and uWORK. If HLD = on then nothing is computed otherwise the LAPACK function DLANGE is
called internally:

value = DLANGE(sNORM, M, N, uA, LDA, uWORK;

where parameters of DLACPY are set in the following way:

- Integer input norm is mapped to the string sNORM: $\left\{0,1\right\}\to \mathtt{\text{"F"}}$ (Frobenius norm), $\left\{2\right\}\to \mathtt{\text{"M"}}$ (max(abs(A(i,j)))), $\left\{3\right\}\to \mathtt{\text{"1"}}$ (one norm) and $\left\{4\right\}\to \mathtt{\text{"I"}}$ (infinity norm).
- M is number of rows of the matrix referenced by uA.
- N is number of columns of the matrix referenced by uA.
- LDA is the leading dimension of the matrix referenced by uA.
- uWORK is the working vector of dimension $\mathtt{\text{LWORK}}\ge \mathtt{\text{M}}$. uWORK is used only for infinity norm, otherwise it is not referenced.

The error flag E is set to on if:

- the reference uA is not defined (i.e. input uA is not connected),
- the reference uWORK is not defined for $\mathtt{\text{norm}}=4$ (i.e. input uWORK is not connected).

See LAPACK documentation [7] for more details.

Use the block MB_DNRM2 for computation of Frobenius norm of a
vector.

Inputs

uA | Input reference to matrix A | Reference |

uWORK | Input reference to working vector WORK | Reference |

norm | The selected matrix norm $\downarrow $0 $\uparrow $4 $\odot $0.00E+00 | Long (I32) |

HLD | Hold | Bool |

Outputs

yA | Output reference to matrix A | Reference |

yWORK | Output reference to working vector WORK | Reference |

value | Return value of the function | Double (F64) |

E | Error indicator | Bool |

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