## Institut für Astronomie und Astrophysik## Abteilung AstronomieSand 1, D-72076 Tübingen, Germany |

hist

- Name
- Purpose
- Category
- SYNTAX:
- Input Parameters
- Keyword Parameters
- SETUP:
- Output Parameters
- Side Effects
- Example
- Revision History

hist

Creates histogram of x values for certain data sets. Result is presented in a new data set allocated in result group.

cafe

hist[,range] [,subgroup][,group][,/add]

range - (optional) Defines range of data points to use. This can be either: - Data point range, denoted by the data point number: <n1>[-], while , are positive numbers. Data point numbers start from zero. Open intervals can be represented with a "*" instead of the number. If only one number is given, a single data point will be referenced. If <val2> is less than all but the interval <val2>.. are referenced. - X value range, denoted by float point numbers: <val1>- , while , represents X values defining the interval to reference. Open intervals can be represented with a * instead of the value. If <val2> is less than <val1> all but the interval <val2>.. is referenced. - Vector of data point indices. The vector is denoted with [val,val,...,val] (indgen may be used also). - Boolean expressions with X/Y values. All values for which this expression is true are referenced. The expression may contain algebraic formulas combined with comparison operators "lt", "le", "eq", "gt", "ge" as used in IDL comparisons. For each data point a keyword is defined which has meaning and can be used for the boolean expression: x - The x-column value. y - The y-column value. error - The error column value. selected - True when the data point is selected. def - True when the data point is defined. x1 - Multi column first column value. x2 - Multi column second column value. x3 - Multi column third column value. To avoid interference with functions which also can be used a lower/upper case distinction is made. IDL funktions should be upper case. Default is to fold the entire data set. subgroup - (optional) The data set (subgroup) for which the histogramming should be applied. This can be either the subgroup number or the file name representing the data set. It is possible to set more than one subgroup, either with numbers in brackets ([]) separated with ","; or denoting filenames with wildcards ("*"). Default are all subgroups in currently used group. group - (optional) The data group for which histogramming should applied. Default is the current group. Must be in range [0..29].

add - Do not overwrite existing subgroups (0) but use the next free one in current result group.

binsize - The width of bins to use. Default: 1. nbins - Number of bins to use. This is the alternative setup which defines the binsize as (max-min)/nbins. max - Maximum limit for histogram. Default is max(x). min - Minimum limit for histogram. Default is min(x).

All data points given as input are summed up within a histogram according their x value modulo a period. The period must be set before.

Creates/Overrides first subgroup in the result group. If /add is used a new subgroup will be created.

> set, binsize=0.5 > hist -> creates new data set containing a histogram of current data set x values with a binning of 0.5

$Id: cafe_hist.pro,v 1.3 2005/02/15 10:40:40 goehler Exp $

Last modified by pro2html on 2005 February 16 at 04:13 UTC

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Jörn Wilms (wilms@astro.uni-tuebingen.de)

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