BUGS_AND_LIMITATIONS · SEE_ALSO
grid_plot -- plots a contour map of the chi-square grid results
This task plots a contour map of the results from the most recent execution of search_grid . The confidence levels as well as the best fit location are marked on the plot. Note that the task leaves you in "cursor input" mode. Type a "?" to obtain a help menu in cursor input mode. Type a "q" to exit back to the CL.
- grid = "" prompt = search_grid file [root_grd.tab]
The name of the search_grid file. There is no default for this file name; however, if the extension is omitted, a "_grd.tab" is added. The grid file is created by means of the search_grid task. It is an STScI table file containing the chisquare values at each grid point. The names of the columns correspond to the value of the "x" free parameter at each grid point. In addition, an extra column is added to give the values of the "y" free parameters at each grid point. Finally, the table header contains information about the model used, the grid points, etc.
- (pkgpars = "") [pset]
The name of the file containing the xspectral package wide parameters. If the name is null ("") then the parameters found for the pkgpars task will be used.
- (plot_title = "Chi-Squared Grid") [string]
Sets the plot title.
- (x_axis_title = "") [string]
X axis label. The program will choose the default title for the x axis variable used in search_grid.
- (y_axis_title = "") [string]
Y axis label. The program will choose the default title for the y axis variable used in search_grid.
- (number_of_levels = 3) [int]
Number of contour levels to be plotted. No more than three contour levels may be plotted.
- (level_delt_= 2.3) [real]
This is the delta from the minimum chi-squared at which to draw the first contour level.
- (level_delt_= 4.61) [real]
This is the delta from the minimum chi-squared at which to draw the second contour level.
- (level_delt_= 9.21) [real]
This is the delta from the minimum chi-squared at which to draw the third contour level.
- (device = "stdgraph") [string]
The output graphics device.
- (cursor = "") [*gcur]
Graphics cursor input.
- (xplotsize = 100) [int]
Number of interpolation points on the X axis.
- (yplotsize = 100) [int]
Number of interpolation points on the Y axis.
- (interpolate = 1) [int]
If value = 1 an interpolation will be performed to round the edges of the contours.
To plot your search_grid results type: grid_plot.
This task normally executes in less than 10 seconds. It does no actual computations, but retrieves stored data and plots it.
The contouring algorithm which is used by this task is not very intelligent. Long valleys may be chopped up into many smaller valleys.