Hello all,

Is there a VI (or does anybody have one) that can integrate unevenly
spaced numerical data?  I know the basic numerical integrator only
works for evenly spaced data (data spaced at a constant interval)..

Thanks for youe help....

Jay  Poret, Ph.D.
AOT, Inc.

Help for the Numeric Integrator.vi shows the formulas.  For the
trapezoidal rule (the simplest one) the integral is the sum of partial
sums which are given by: 1/2(x[i] + x[i + 1])*dt.

If you change dt to dt(i) = t[i+1] - t[i], I think this should give
you a reasonable approximation. The more complex rules cannot use this
approach.  The trapezoidal rule simply sums the area under the
trapezoids created by connecting the t[i], x[i], x[i+1], t[i+1] dots,
so this change should not introduce any errors.

John,

Thanks for the reply...I believe I solved the problem by creating a VI
based on fitting my data with a cubic spline and then generating new y
data based on evenly spaced x data.  It actually works pretty well..
The trick is to use the two cubic spline Vis in the processing
tools....

Radman,  could you go into more detail on what it is you are doing
here?  This is exactly what I want to do and I'm not sure what you are
talking about by using two cubic spline VI's