Difference between revisions of "IXTdataset 2d"
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Revision as of 12:57, 2 April 2008
An IXTdataset_2d is an object that stores signal and error data against two independent dimensions (the x and y axes). Title and label information is also stored. These are used for manipulating and visualising a single spectrum.
Two dimensional plotting can be used to visualise the data and many functions exist to manipulate it given in the user manual
Fields
IXTdataset_2d objects contain the following fields
| Field | Type | Description |
| base | IXTbase | Object required for internal use |
| title | char | Title of the dataset used in plotting |
| signal | real (ptr) | Signal data |
| error | real (ptr) | Standard error |
| s_axis | IXTaxis | object containing the signal axis label and units code information |
| x | real (ptr) | First 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 | logical | True if signal is a distribution on x (e.g. counts/microsecond) False if signal is not a distribution on x (e.g. counts) |
| y | real (ptr) | Second independent variable data (i.e. y data). If point data this will be the point positions in the y axis. If histogram data, this will be the bin boundaries in the y axis |
| y_axis | IXTaxis | object containing the y axis label and units code information |
| y_distribution | logical | True if signal is a distribution on y (e.g. counts/spectrum) False if signal is not a distribution on y (e.g. counts) |
Constructing an IXTdataset_2d Object
The constructor for an IXTdataset_2d can be used to create a full IXTdataset_2d object using the following syntax
>> ww = IXTdataset_2d(base, 'title', [signal], [error], s_axis,... [x], x_axis, [x_distribution], [y], y_axis, y_distribution )
- Size(signal,1), size(error,1), Length(x) must all be equal
- Size(signal,2), size(error,2), Length(y) must all be equal
- x and y must be one dimensional arrays
- Signal and error must be two dimensional arrays of size (length(x), length(y))
- s_axis, x_axis and y_axis must be properly constructed IXTaxis objects
- x_distribution and y_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
>> ww = IXTdataset_2d(x, y, 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, x_axis and y_axis will contain blank objects
- x_distribution and y_distribution will be FALSE
datasets can also be made using commands found in input and output functions
Changing Values in an IXTdataset_2d 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
>> ww.title = 'mytitle'
will set the title in w to 'mytitle'
Examples
Two Identical Scripts to Construct an IXTdataset_2d From a Function
Here, assume that a function my_func is some unusual function of the form
function z = my_polynom(x, y, pin)
[x, y] = meshgrid(x, y)
z = pin(1).*x.^6 + pin(2).*y.*sin(x) + pin(3).*x
The function
x = 1:300
y = 1:2:60
z = my_func(x, y, [2, 3, 2]) % generate z values
title = 'my unusual function'
xaxis = IXTaxis('x')
yaxis = IXTaxis('y')
zaxis = IXTaxis('z')
e = zeros(size(z)) % need error values for full construction
w = IXTdataset_2d(IXTbase, title, z, e, yaxis, x, xaxis, false, y, yaxis, false)
dl(w) % plot the data
gives the same results as
x = 1:300
y = 1:2:60
w = IXTdataset_2d(x, y) % create dataset with blank signal and e values
w.title = 'my unusual function'
w.x_axis = IXTaxis('x')
w.y_axis = IXTaxis('y')
w.s_axis = IXTaxis('z')
w = func_eval(w, [2 3 2])
dl(w)