NAG Library Routine Document

g01ahf (withdraw_plot_scatter_normal)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{x}\left(\mathbf{nobs}\right)$ – Real (Kind=nag_wp) arrayInput

On entry: the vector of data values.

Constraint: all data values must not be equal.

2:     $\mathbf{nobs}$ – IntegerInput

On entry: the number of data values.

Constraint: $\mathbf{nobs}\ge 2$.

3:     $\mathbf{nstepx}$ – IntegerInput

On entry: the number of steps (character positions) to be plotted in the $x$-direction. If the supplied value of nstepx is less than $10$, the value $10$ will be used by g01ahf. The maximum value for nstepx is the number of character positions available on the chosen output device less $15$, up to a maximum of $133$. If nstepx exceeds $133$ on input, the value $133$ will be used by the routine.

4:     $\mathbf{nstepy}$ – IntegerInput

On entry: the number of steps (character positions) to be plotted in the $y$-direction. If the supplied value of nstepy is less than $10$, the value $10$ will be used by g01ahf. There is no maximum value for nstepy, but you should bear in mind that ($\mathbf{nstepy}+5$) records (lines) of output are generated by the routine.

5:     $\mathbf{istand}$ – IntegerInput

On entry: indicates whether the residuals are to be standardized prior to plotting.

If $\mathbf{istand}>0$, the elements of x are standardized to zero mean and unit standard deviation.

6:     $\mathbf{iwork}\left(\mathbf{nobs}\right)$ – Integer arrayWorkspace

7:     $\mathbf{nscores}\left(\mathbf{nobs}\right)$ – Real (Kind=nag_wp) arrayOutput

On exit: the Normal scores in ascending magnitude.

8:     $\mathbf{lwork}$ – IntegerInput

On entry: this argument is no longer referenced, but is included for backwards compatability.

9:     $\mathbf{xsort}\left(\mathbf{nobs}\right)$ – Real (Kind=nag_wp) arrayOutput

On exit: the data values, sorted into descending order, and standardized if istand was positive on entry.

10:   $\mathbf{xbar}$ – Real (Kind=nag_wp)Output

On exit: the mean of the data values.

11:   $\mathbf{xstd}$ – Real (Kind=nag_wp)Output

On exit: the standard deviation of the data values.

12:   $\mathbf{ifail}$ – 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, $\mathbf{nobs}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{nobs}\ge 2$.

$\mathbf{ifail}=2$

All the supplied data values are equal.

$\mathbf{ifail}=-99$

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

10.1

Program Text

Program Text (g01ahfe.f90)

10.2

Program Data

Program Data (g01ahfe.d)

10.3

Program Results

Program Results (g01ahfe.r)