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Jun 5, 2014 1:48 AM
(2217 views)

Hello,

I'm a new user to JMP and I have a simple question to seek your help.

I would like to ask JMP to plot a graph using an input equation, how do I do that?

The equation is as follows:

(c1-constant1)/(constant2 - constant1) = (constant3 * c2)/(1-(1-constant3)*c2)

where c1 and c2 = column 1 and column 2 respectively.

i.e. I have two columns of experimental data (column 1 and column 2) and ultimately I would like to plot column 1 against column 2 and fit it using the equation above.

Thanks for the help!

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Jul 12, 2014 10:46 AM
(2635 views)

Solution

Xan's on the right track for you here.

The Nonlinear platform will fit your equation, finding values for your parameters.

To start, you'll need to move all your parameters ("constants") as you described them, to one side of your equation. Essentially, you'll solve your equation for either C1 or C2.

I solved it for C1 here:

`c1 = ((constant3 * c2)/(1-(1-constant3)*c2) * (constant2 - constant1)) + constant1`

Then, in your existing data table create a column for a new "Predicted C1", using the Parameters option in the upper left of the Formula Editor to create your "constants".

Finally, use the Analyze -> Modeling -> Nonlinear menu to get to the Nonlinear platform.

You'll put your "Predicted C1" column in X, Predictor role, and your original C1 column in the Y, Response role.

Read more about the Nonlinear platform in the online documentation.

-Jeff

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Jul 5, 2014 3:12 AM
(1884 views)

hi jm,

i would try to put each side of the equation as a new formula column. Then use the profiler and put both columns in the "Y, Prediction formula". Under the Graph menu there are a few different profilers you can choose between according to what gives you a better picture.

ron

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Jul 7, 2014 1:31 PM
(1884 views)

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Jul 10, 2014 6:51 PM
(1884 views)

Thanks, that helped!

The plot now shows a curve of the function, together with my data points.

Supposed I can only enter an initial guess for constant 1, how do I ask JMP to start with the initial guess value and continue iterating until the Chi Square does not change for a certain number of iterations or the percent change in the normalized Chi Square is less than the Allowed Error set by me?

Would need the final value of constant, Chi Sq and R value at the end of the curve fit for my data points...

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Jul 11, 2014 6:10 AM
(1884 views)

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Jul 12, 2014 10:46 AM
(2636 views)

Xan's on the right track for you here.

The Nonlinear platform will fit your equation, finding values for your parameters.

To start, you'll need to move all your parameters ("constants") as you described them, to one side of your equation. Essentially, you'll solve your equation for either C1 or C2.

I solved it for C1 here:

`c1 = ((constant3 * c2)/(1-(1-constant3)*c2) * (constant2 - constant1)) + constant1`

Then, in your existing data table create a column for a new "Predicted C1", using the Parameters option in the upper left of the Formula Editor to create your "constants".

Finally, use the Analyze -> Modeling -> Nonlinear menu to get to the Nonlinear platform.

You'll put your "Predicted C1" column in X, Predictor role, and your original C1 column in the Y, Response role.

Read more about the Nonlinear platform in the online documentation.

-Jeff