ZunZun.com - User Defined Function Fitting Interface

Introduction

Please select an option from the pull-down menu above.

Text Function Editor

Cut-and-paste text or edit your function here

Example User Defined Functions

 C * X + 51.0 + pi ** e - [Y * A] + B  # coefficients are A, B and C

 Scale * exp(X) * exp(Y) + offset  # Scale and offset are coefficents in this example

 # the following three examples are equivalent 
 power(X+Y+shift, C0)  # shift and C0 are coefficients in this example 
 [X+Y+shift] ** C0     # shift and C0 are coefficients in this example
 (X+Y+shift) ** C0     # shift and C0 are coefficients in this example

MXY + B  # This fails, it should be written as M*X*Y + B

Links To Help For Pre-Defined Internal Functions

Exponents And Logarithms:	exp log log10 log2
Arithmetic Operations:	power mod
Miscellaneous:	sqrt square fabs sign
Hyperbolic Trig Functions:	arcsinh arccosh arctanh sinh cosh tanh
Other Special Functions:	sinc
Trigonometric Functions:	sin cos tan arcsin arccos arctan hypot arctan2 deg2rad rad2deg

Pre-Defined Constants

pi	3.1415926535897931
e	2.7182818284590451

Text data editor

Cut-and-paste text or edit data here

Convert commas to spaces (1,2,0,3 yields 1 2 0 3)
Use comma as decimal separator (1,203 = 1.203)
Remove commas from text (1,2,0,3 yields 1203)

Standard Unweighted Fitting: no weights required
Weighted Fitting: each data point requires a weight

This data is provided as an example, cut and paste
as needed to model your data. All lines of text
that do not begin with a number are ignored.

Weighted fitting requires an additional number to
be used as a weight when fitting. The site does
not calculate any weights, which are used as:
error = weight * (predicted - actual)
You must provide any weights you wish to use.

X      Y       Z
  3.017  2.175   0.320
  2.822  2.624   0.629
  2.632  2.839   0.950
  2.287  3.030   1.574
  2.207  3.057   1.725
  2.048  3.098   2.035
  1.963  3.115   2.204
  1.784  3.144   2.570
  1.712  3.153   2.721
  2.972  2.106   0.313
  2.719  2.542   0.643
  2.495  2.721   0.956
  2.070  2.878   1.597
  1.969  2.899   1.758
  1.768  2.929   2.088
  1.677  2.939   2.240
  1.479  2.957   2.583
  1.387  2.963   2.744
  2.843  1.984   0.315
  2.485  2.320   0.639
  2.163  2.444   0.954
  1.687  2.525   1.459
  1.408  2.547   1.775
  1.279  2.554   1.927
  1.016  2.564   2.243
  0.742  2.568   2.581
  0.607  2.571   2.753

Fitting Target

Here you can select the desired fitting target.

Lowest sum of squared absolute error
Lowest sum of squared orthogonal distance
Lowest sum of squared relative error
Lowest sum of absolute value of absolute error
Lowest sum of absolute value of relative error
Lowest peak absolute value of absolute error
Lowest peak absolute value of relative error
Lowest Akaike Information Criterion
Lowest Bayesian Information Criterion

Data labels for graphs

Here you can enter the X, Y and Z data labels to be printed on the report graphs.

Label for first independent data (X)

Label for second independent data (Y)

Label for dependent data (Z)

Graph scaling and lin/log control

Here you can choose the scaling of the data
plots, the 3D scatterplots and the VRML files.
Log plots require data values greater than zero.

X Scale

Y Scale

Z Scale

Autoscale +/- 1%
Autoscale +/- 2.5%
Autoscale +/- 5%
Autoscale +/- 10%
Autoscale +/- 25%
Autoscale +/- 50%
Autoscale +/- 100%
Autoscale +/- 150%
Autoscale +/- 200%
Manual Scale

Max X:
Min X:

Linear Scaling
Logarithmic Scaling

Autoscale +/- 1%
Autoscale +/- 2.5%
Autoscale +/- 5%
Autoscale +/- 10%
Autoscale +/- 25%
Autoscale +/- 50%
Autoscale +/- 100%
Autoscale +/- 150%
Autoscale +/- 200%
Manual Scale

Max Y:
Min Y:

Linear Scaling
Logarithmic Scaling

Autoscale +/- 1%
Autoscale +/- 2.5%
Autoscale +/- 5%
Autoscale +/- 10%
Autoscale +/- 25%
Autoscale +/- 50%
Autoscale +/- 100%
Autoscale +/- 150%
Autoscale +/- 200%
Manual Scale

Max Z:
Min Z:

Linear Scaling
Logarithmic Scaling

Graph size

Here you can choose the size of the report graphs. Smaller size files load quickly,
with less resolution while large files show more resolution but load more slowly.

320 x 240 (fastest)
500 x 400
640 x 480
700 x 500
800 x 600
900 x 700
1024 x 768
1280 x 1024
1600 x 1200 (slowest)

Scientific Notation

Here you can control scientific notation on the data plots, the
3D surfaces, the contour plots, and the VRML model files.

X Control

Y Control

Z Control

On
Off
Auto

3D rotation angles

Here you can select and rotate the 3D scatter and surface plots.

Rotation view angle in degrees
Vertical view angle in degrees

VRML Options

Here you can set various characteristics of the VRML 2.0 files.

	Surface Plot - Model Surface Opacity
On Off	Surface Plots - Vertical Lines Connecting Surface and Data Points
On Off	Surface Plots - Display Data Points
On Off	Scatter and Surface Plots - Bounding Cube

	Absolute Error Plot - Absolute Error Zero Plane Opacity
On Off	Absolute Error Plot - Vertical Lines Connecting Zero Plane and Absolute Error Points
On Off	Absolute Error Plot - Display Absolute Error Points
On Off	Absolute Error Plot - Bounding Cube

	Relative Error Plot - Relative Error Zero Plane Opacity
On Off	Relative Error Plot - Vertical Lines Connecting Zero Plane and Relative Error Points
On Off	Relative Error Plot - Display Relative Error Points
On Off	Relative Error Plot - Bounding Cube

	Percent Error Plot - Percent Error Zero Plane Opacity
On Off	Percent Error Plot - Vertical Lines Connecting Zero Plane and Percent Error Points
On Off	Percent Error Plot - Display Percent Error Points
On Off	Percent Error Plot - Bounding Cube

The fitting source code for the site software is at the Python Equations II Google Code Repository.

Superior quality PDF on practical curve fitting: Fitting Models to Experimental Data

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