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.