# Name

HPL_pdlange Compute ||A||.

# Synopsis

`#include "hpl.h"`

`double` `HPL_pdlange(` `const HPL_T_grid *` `GRID`, `const HPL_T_NORM` `NORM`, `const int` `M`, `const int` `N`, `const int` `NB`, `const double *` `A`, `const int` `LDA` `);`

# Description

HPL_pdlange returns the value of the one norm, or the infinity norm, or the element of largest absolute value of a distributed matrix A: max(abs(A(i,j))) when NORM = HPL_NORM_A, norm1(A), when NORM = HPL_NORM_1, normI(A), when NORM = HPL_NORM_I, where norm1 denotes the one norm of a matrix (maximum column sum) and normI denotes the infinity norm of a matrix (maximum row sum). Note that max(abs(A(i,j))) is not a matrix norm.

# Arguments

```GRID    (local input)                 const HPL_T_grid *
On entry,  GRID  points  to the data structure containing the
process grid information.
```
```NORM    (global input)                const HPL_T_NORM
On entry,  NORM  specifies  the  value to be returned by this
function as described above.
```
```M       (global input)                const int
On entry,  M  specifies  the number  of rows of the matrix A.
M must be at least zero.
```
```N       (global input)                const int
On entry,  N specifies the number of columns of the matrix A.
N must be at least zero.
```
```NB      (global input)                const int
On entry,  NB specifies the blocking factor used to partition
and distribute the matrix. NB must be larger than one.
```
```A       (local input)                 const double *
On entry,  A  points to an array of dimension  (LDA,LocQ(N)),
that contains the local pieces of the distributed matrix A.
```
```LDA     (local input)                 const int
On entry, LDA specifies the leading dimension of the array A.
LDA must be at least max(1,LocP(M)).
```