Enhanced Statistical Features in SPAYN Version 1.7.2
Introduction
When performing statistical analyses it is often necessary to compute transformations
of the observed data. This transformation may only involve a single parameter,
or it may be a complicated function of several different variables. SPAYN
has a new feature for generating user-defined parameters as functions of existing
variables and/or constants.
A new Factor plot option allows the user to plot the percentage of explained
variation versus the number of factors, for a given Principal Components or
Factor Analysis. It is extremely useful to have a graphical representation of
the contribution each factor makes to explaining the variance in the original
data. In particular when deciding how many independent factors to utilize in
further calculations.
The SPAYN simulation interface currently generates worst-case
and Monte Carlo models that can be simulated directly with an external simulator
such as SmartSpice. The new SPAYN /SABER interface
generates these models utilizing SABER simulator syntax. Thus
providing the flexibility of several different external simulator options.
Variable Transformation
It is frequently the case when analyzing data that some form of variable transformation
is required prior to performing any calculations. Alternatively an modeling
engineer may be interested in a particular parameter that is extremely difficult
to measure, but can be computed in terms of easily measurable variables. SPAYN
now has the capability to generate new parameters as functions of existing variables
and/or user-defined constants. Once the new parameter has been computed it can
be saved as a standard SPAYN variable and treated as such for
further calculation or analysis.
The Variable Transformation function is available in the Parameter Matching
Window, which is accessed by clicking on Analysis->Matching... from the main
SPAYN window. Parameters P1 and P2 can then be chosen using the
two pulldown menus and the scrolled Matching Quantity Window is utilized to
select the required transformation function. The transformation may also only
involve P1 and a constant. The Generate button will then compute the new variable,
and on successful completion a histogram will appear in the graphics window.
Pressing the store button allows the new parameter to be saved as a standard
SPAYN variable. The following example demonstrates the full capabilities
of this feature.
Example
Consider constructing the new variable:
i. Select P1 = PHI, toggle the Parameter Matching
quantity sqrt(P1), press
the generate button and store the new variable as TMP1
ii. Select P1 = VBS and P2 = TMP1, toggle
the Parameter Matching quantity
P1/P2, press the generate button and store the new variable as TMP2.
iii. Select P1 = TMP2 and Constant = 5.24, toggle
the Parameter Matching quantity
P1+P2, press the generate button and store the new variable as TMP3.
iv. Select P1 = GAMMA and P2 = TMP3, toggle
the Parameter Matching quantity
P1*P2, press the generate button and store the new variable as TMP4.
v. Select P1 = VBI and P2 = TMP4, toggle
the Parameter Matching quantity P1+P2,
press the generate button and store the new variable as VTH as required.