topic Re: looking for a platform to handle harmonic oscillation in Discussions

looking for a platform to handle harmonic oscillation

LMSteve — Wed, 22 Mar 2017 15:06:49 GMT

Specifically looking for a curve fitting platform for underdamped oscillation

Re: looking for a platform to handle harmonic oscillation

txnelson — Wed, 22 Mar 2017 15:34:13 GMT

In JMP 13, have you looked at

Anaylze==>Specialized Modeling==>Fit Curve

Re: looking for a platform to handle harmonic oscillation

LMSteve — Wed, 22 Mar 2017 15:36:16 GMT

Hacking through that now - thanks. My data should create a an exponentially decaying sinusoid. Trying to figure out how to make JMP do it.

Re: looking for a platform to handle harmonic oscillation

vince_faller — Wed, 22 Mar 2017 21:09:21 GMT

You can give custom equations and parameters in the nonlinear platform. Also Under specialized models.

Re: looking for a platform to handle harmonic oscillation

LMSteve — Thu, 23 Mar 2017 14:32:09 GMT

Thanks y'all. I appreciate the suggetions. I was able to answer my client's question by fitting an exponential decay curve through my data rather than generate the oscillating underdamped plot. I would like to figure that part out though. I need to find some examples to learn from. Thanks again.

Re: looking for a platform to handle harmonic oscillation

vince_faller — Mon, 27 Mar 2017 19:10:35 GMT

Are you trying to just plot an underdamped oscillator? Or are you trying to fit beta and w0? The below script will actually fit.

Names Default to here(1);
dt = New Table("Harmonic Oscillator", 
	New Table Variable("beta", .3),
	New Table Variable("w0", .4),
	New Column("t", set values(0::50)), 
	New Column("Cos t", formula(Cos(t))), 
	New Column("Damped Cos t", Formula(
		exp(-:beta*:w0*:t)*cos(:w0*t) + random normal(0, .01) //just adding noise
	)), 
	New Column("Predictor", 
		Formula(
			Parameter({pbeta = .2, pw0 = .5}, 
				exp(-pbeta*pw0*:t)*cos(pw0*t)
			)
		)
	)
);

dt << Nonlinear( Y( :Damped Cos t ), X( :Predictor ), Newton );

To give you this. notice how my actual beta/w0 was .3/.4 but I started my predictor with .2/.5

Is this sort of what your'e looking for?

Re: looking for a platform to handle harmonic oscillation

LMSteve — Mon, 27 Mar 2017 20:18:32 GMT

Exactly!!! You hit a grand slam! Many thanks!!