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Дата изменения: Thu Jun 29 00:01:13 2006
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XMM-Newton Science Analysis System


implot (implot-2.17.1) [xmmsas_20060628_1801-7.0.0]

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Maximum number of sources.

It may be desirable to apply (in addition to the source selection described above) some definite upper limit to the number of sources to be plotted - say, to plot only the first 50 brightest sources. Such a limit may be difficult or impossible to achieve by use of the expression parameter. For this reason, an ncut parameter has been provided. However, this parameter alone cannot provide full versatility. It is not sufficient just to specify the number of sources to keep: it is also necessary to determine which sources to keep. This means that the sources must be sorted into a series before the series can be truncated after the ncutth member. Parameters withncut, ncutsortstyle and ncutsortexpression have been provided to allow the sources to be sorted.

Parameter ncutsortstyle has the following allowed values:

• radiusup: sources are ordered in order of increasing radius (see subsection 3.5).
• radiusdown: sources are ordered in order of decreasing radius (see subsection 3.5).
• rownumber: sources are ordered in order of increasing row number in the source table.
• expr: for this value, the task looks in parameter ncutsortexpression for an expression involving column names. This expression is evaluated and the sources are then ordered in increasing order of the resulting value.