Extrapolating Linear Best Fit

[Oli.P]

Overview 

This is an example using a Temperature vs Pressure Graph using the ExtrapXLinearBestFit SubVI. The VI reports the X Intercept and the Slope and outputs an array of (X,Y) coordinates for plotting on a graph.

Description

The 'Linear Best Fit' VI included with LabVIEW doesn't extrapolate back to the X axis.  This is a very simple idea of how to do so.

The SubVI extends a linear line of best fit back to the X axis as well as extending beyond the end of the data so that you can place it on top of your existing curve on a graph.

Requirements

• LabVIEW 2012 (or compatible)

Steps to Implement or Execute Code

1.  Run the VI.
2. Get the Slope and Absolute Zero plotting on the graph.

Additional Information or References 

VI Snippet

**This document has been updated to meet the current required format for the NI Code Exchange.**

[harisiam]

hey, oli.. i think this will not work..

[Oli.P]

Any particular reason?

[harisiam]

no particular reason i cant tell.. i was also working on the tangential fit to a curve,.. i got it.. nd its somewhat huge code..this one i tried.. but not working with my graph..

[Oli.P]

It should work fine, it's just an extension of the existing LabVIEW Linear Best Fit VI.  The inputs X and Y are your curve data, then the outputs Extrapolated X and Y are a line of best fit extended to the X axis and slightly beyond your original curve.  It works for me.  I've added an example of how it could be used.