Error Propagation Class

This class automatically performs error propagation in Matlab expressions.

Description

This class, called "meas" (meaning measurement with uncorrelated error), contains two elements. A "meas" can be created with the constructor function:

>> d = meas();

and values can be assigned to the two elements.

>> d.value = 1;
>> d.error = .3;

The values can also be displayed:

>> d
1 +/- 0.3

I overloaded the +,-,*,/,^,>,<,==,>=,<= operators to perform the error propagation for each of these operators. The comparison operators work to within 1-sigma. For example, (1.0 +/- .3) == (.9 +/- .3) would return "true".

In this early version, this only works for single numbers, and just for the operators listed above. In the future, I plan to overload many common functions (sin(x) and such...), and make support for matrices and arrays. Comments and changes are most welcome, especially since this is my first Matlab code in which I have made my own class.

Thanks to Kevin Murphy's site,
http://www.cs.ubc.ca/~murphyk/Software/matlabObjects.html
for helpful basic information on writing a class.

• MATLAB release: MATLAB 7.4 (R2007a)
• Other requirements: Should be platform-independent, although I wrote this in Windows XP. To install, unzip the archive, and put the directory into which it is unzipped into the Path. Make sure the directory is named "@meas"

[Stefan Bollmann]

Thank you for this class. But I think there are some things to watch. Try z=meas(3,1) and then z/z.

[belhaoua abdelkrim]

Thank you! It's a very interesting class and very useful.

[Kenneth Wong]

Thank you for this useful class!

May I suggest adding functionality to perform multiplication of scalars with "meas"s? i.e. 10 * d = 1 +/- 3

Thanks again!

[Thomas Pieper]

Excellent idea! Please, please continue to expand the class furthermore. Thank you!

[Dimitri Shvorob]

It's 'propAgation'.