Hello samgg007,
Perhaps the quickest way to implement Romberg integration method in your project is to use a .m file with MathScript, then you can use the logic of the .m file in your VI to make it more efficient.
Working with .m File Scripts in NI LabVIEW for Text Based Signal Processing, Analysis, and Math:
http://www.ni.com/white-paper/7006/en/
Rombint.m:
http://www.mathworks.com/matlabcentral/fileexchange/34-rombint-m
Let me know if this helped you, kind regards.
David P.
National Instruments
Applications Engineer
www.ni.com/soporte