29.9.8 Histograms

Histograms can be displayed in a graphics window using a bar chart (or printed in the console window, as described in Section  30.8). The abscissa of the chart is the desired solution quantity and the ordinate is the percentage of the total number of cells.

Steps for Generating Histogram Plots

You can create a histogram plot of solution data using the Histogram dialog box (Figure  29.9.12).

Plots Histogram Set Up...

Figure 29.9.12: The Histogram Dialog Box

The steps for generating a histogram plot are as follows:

1.   Choose the scalar quantity to be plotted in the Histogram Of drop-down list. Select a category in the upper list and then select the desired quantity in the lower list. (See Chapter  31 for an explanation of the variables in the list.)

2.   Set the number of data intervals that will be plotted in the histogram in the Divisions field. By default there will be 10 intervals ("bars'') in the histogram plot. If you want to resolve the histogram plot to finer intervals, increase the number of Divisions. You may want to click the Compute button to update the Min and Max fields when you are trying to decide how many divisions to plot.

3.   Select the face or cell zone under Zones for which you want results plotted or printed. If all zones are selected, then the entire domain will be plotted. You can also plot histograms based on the selected Zone Types.

4.   Set the option described below, if desired, or modify the attributes of the axes or curves as described in Section  29.9.9 and Section  29.9.10.

5.   Click the Plot button to generate the histogram plot in the active graphics window.

6.   Click the Print button to print out your histogram results on individual zones, or the entire domain. Similarly, you can click the Compute button to calculate your histogram results on individual zones, or the entire domain.

Options for Histogram Plots

Other than the axis and curve attribute controls mentioned in the procedure above, the only option for histogram plotting is the ability to specify a subrange of values to be plotted.

Specifying the Range of Values Plotted

By default, the range of values included in the histogram plot is automatically set to the range of values in the entire domain for the selected variable. If you want to focus in on a smaller range of values, you can restrict the range to be displayed.

To manually set the range of values, turn off the Auto Range option in the Histogram dialog box. The Min and Max fields will become editable, and you can enter the new range of values to be plotted. To show the default range at any time, click the Compute button and the Min and Max fields will be updated.

You can also choose to base the minimum and maximum values on the range of values on the selected surfaces, rather than in the entire domain. To do this, turn off the Global Range option in the Histogram dialog box. The Min and Max values will be updated when you next click Compute.