Difference between revisions of "IXTdataset 1d"

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Revision as of 15:30, 20 March 2008

An IXTdataset_1d is an object that stores signal and error data against one independent dimension (the x axis). Title and label information is also stored. These are used for manipulating and visualising a single spectrum.


One dimensional plotting can be used to visualise the data and many functions exist to manipulate it given in the user manual


Fields

IXTdataset_1d objects contain the following fields


Field Description
IXTbase Object required for internal use
title Title of the dataset used in plotting
signal Signal data
error Standard error
s_axis IXTaxis object containing the signal axis label and units code information
x Independent variable data (i.e. x data). If point data this will be the point positions in the x axis. If histogram data, this will be the bin boundaries in the x axis
x_axis IXTaxis object containing the x axis label and units code information
x_distribution True if signal is a distribution on x (e.g. counts/microsecond) False if signal is not a distribution on x (e.g. counts)


Constructing an IXTdataset_1d Object

The constructor for an IXTdataset_1d can be used to create a full IXTdataset_1d object using the following syntax

>> w = IXTdataset_1d(base, 'title', [signal], [error], s_axis, [x], x_axis, [x_distribution])
  • Length(signal), Length(error), Length(x) must all be equal
  • signal, error and x must be one dimensional arrays
  • s_axis and x_axis must be properly constructed IXTaxis objects
  • x_distribution must be a logical value (1 or 0, TRUE or FALSE)
  • base must be a properly constructed IXTbase object

Datasets without title and label information may be constructed using the syntax

w = IXTdataset_1d(x, signal, error)
  • signal and error may be omitted. If so, w.signal and/or w.error will contain an array of 0's matching the dimensions of the x data
  • Title, s_axis and x_axis will contain blank objects
  • x_distribution will be FALSE


datasets can also be made using commands found in input and output functions


Changing Values in an IXTdataset_1d object

The fields in the object are accessible on the matlab command line. Therefore the values of the fields can be changed easily, for instance

>> w.title = 'mytitle'

will set the title in w to 'mytitle'


Examples

Two Identical Scripts to Construct an IXTdataset_1d From a Function


Here, assume that a function my_func is some unusual function of the form

function y = my_polynom(x, pin) y = pin(1).*x.^6 + pin(2).*x.*sin(x) + pin(3).*x


The function


x = 1:300

y = my_func(x, [2, 3, 2]) % generate y values

title = 'my unusual function'

xaxis = IXTaxis('Independent Variable')

yaxis = IXTaxis('Dependent Variable')

e = zeros(size(x)) % need error values for full construction

w = IXTdataset_1d(IXTbase, title, y, e, yaxis, x, xaxis, false)

dl(w) % plot the data


gives the same results as


x = 1:300

w = IXTdataset_1d(x) % create dataset with blank y and e values

w.title = 'my unusual function'

w.x_axis = IXTaxis('Independent Variable')

w.y_axis = IXTaxis('Dependent Variable')

w = func_eval(w, [2 3 2])

dl(w)