NAG Library Routine Document

D03RZF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     LEVEL – INTEGERInput

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

Constraint: $1\le \mathbf{LEVEL}\le \mathbf{NLEV}$.

2:     NLEV – INTEGERInput

3:     XMIN – REAL (KIND=nag_wp)Input

4:     YMIN – REAL (KIND=nag_wp)Input

5:     DXB – REAL (KIND=nag_wp)Input

6:     DYB – REAL (KIND=nag_wp)Input

7:     LGRID($*$) – INTEGER arrayInput

8:     ISTRUC($*$) – INTEGER arrayInput

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

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: NLEV, XMIN, YMIN, DXB, DYB, LGRID and ISTRUC as supplied to MONITR must be passed unchanged to D03RZF.

9:     NPTS – INTEGEROutput

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

10:   X(LENXY) – REAL (KIND=nag_wp) arrayOutput

11:   Y(LENXY) – 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:   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:   IFAIL – INTEGERInput/Output

On entry: IFAIL must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this parameter you should refer to Section 3.3 in the Essential Introduction 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 parameter, 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., $\mathbf{LENXY}<\mathbf{NPTS}$.

7  Accuracy

8  Further Comments

9  Example