**Graph scaling and lin/log control**
Here you can choose the scaling of the data

plots and the 3D scatterplots.

Log plots require data values greater than zero.

X Scale (2D Only) | | Y Scale (2D Only) | | Z Scale (2D Only) |

| | | | |

**Animation and Graph size**
Here you can choose the size of the graphs. Smaller size files load quickly,

with less resolution while large files show more resolution but load more slowly.

**Hold Coefficients Constant**
Here you can enter values to hold coefficients constant during fitting.

Leave the entry field blank to let the coefficient fit normally.

Note that coefficient bounds are overridden by holding a coefficient constant.

s

^{2} = (ax+b)

^{2} + (cy+d)

^{2}z = (s

^{2}/r) / (1+(1-(k+1)(s/r)

^{2})

^{1/2}) + A4*s

^{4} + A6*s

^{6}**Estimated Initial Coefficients**
Here you can enter values for initial parameter estimates.

Few users will need this section, as the site estimates initial

parameters using the Differential Evolution genetic algorithm

for both non-linear equations and non-Gaussian fitting targets.

s

^{2} = (ax+b)

^{2} + (cy+d)

^{2}z = (s

^{2}/r) / (1+(1-(k+1)(s/r)

^{2})

^{1/2}) + A4*s

^{4} + A6*s

^{6}**Coefficients Bounds**
Here you can enter coefficient upper and lower bounds. Leave the

entry fields blank to let the coefficients fit without bounds.

Note that holding a coefficient constant overrides these bounds.

s

^{2} = (ax+b)

^{2} + (cy+d)

^{2}z = (s

^{2}/r) / (1+(1-(k+1)(s/r)

^{2})

^{1/2}) + A4*s

^{4} + A6*s

^{6}