NAG Library Routine Document

d03rzf  (dim2_gen_order2_rectilinear_extractgrid)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{level}$ – IntegerInput

On entry: the grid level at which the coordinates are required.

Constraint: $1\le \mathbf{level}\le \mathbf{nlev}$.

2:     $\mathbf{nlev}$ – IntegerInput

3:     $\mathbf{xmin}$ – Real (Kind=nag_wp)Input

4:     $\mathbf{ymin}$ – Real (Kind=nag_wp)Input

5:     $\mathbf{dxb}$ – Real (Kind=nag_wp)Input

6:     $\mathbf{dyb}$ – Real (Kind=nag_wp)Input

On entry: nlev, xmin, ymin, dxb and dyb as supplied to monitr must be passed unchanged to d03rzf.

7:     $\mathbf{lgrid}\left(*\right)$ – Integer arrayInput

Note: the dimension of the array lgrid must be at least $\mathbf{nlev}$.

On entry: lgrid as supplied to monitr must be passed unchanged to d03rzf.

8:     $\mathbf{istruc}\left(*\right)$ – Integer arrayInput

Note: the dimension of the array istruc must be at least $\mathbf{lgrid}\left(\mathbf{nlev}\right)+2\times \mathit{nrows}+\mathbf{npts}+1$ where $\mathit{nrows}$ is stored in $\mathbf{istruc}\left(\mathbf{lgrid}\left(\mathbf{nlev}\right)\right)$ and is the number of rows in the grid at level nlev.

On entry: istruc as supplied to monitr must be passed unchanged to d03rzf.

9:     $\mathbf{npts}$ – IntegerOutput

On exit: the number of grid points in the grid level level.

10:   $\mathbf{x}\left(\mathbf{lenxy}\right)$ – Real (Kind=nag_wp) arrayOutput

11:   $\mathbf{y}\left(\mathbf{lenxy}\right)$ – Real (Kind=nag_wp) arrayOutput

On exit: $\mathbf{x}\left(\mathit{i}\right)$ and $\mathbf{y}\left(\mathit{i}\right)$ contain the $\left(x,y\right)$ coordinates respectively of the $\mathit{i}$th grid point, for $\mathit{i}=1,2,\dots ,\mathbf{npts}$.

12:   $\mathbf{lenxy}$ – IntegerInput

On entry: the dimension of the arrays x and y as declared in the (sub)program from which d03rzf is called.

Constraint: $\mathbf{lenxy}\ge \mathbf{npts}$.

13:   $\mathbf{ifail}$ – IntegerInput/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this argument, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6

Error Indicators and Warnings

$\mathbf{ifail}=1$

On entry,	$\mathbf{level}<1$,
or	$\mathbf{level}>\mathbf{nlev}$.

$\mathbf{ifail}=2$

The dimension of the arrays x and y is too small for the requested grid level, i.e., $\mathbf{lenxy}<\mathbf{npts}$.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 3.9 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 3.8 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example