Causes of chaos: an application of the Bretagnon model

In the following plots we report contour plots of the period of precession in \omega, of sigma for the integration with Jupiter and Saturn and the normal version of SWIFT_WHM, and the orbital elements of saturn for this integration.
 

In this table we report the average value and the standard deviation of the difference in \sigma between the integration with Jupiter and Saturn, and those that used solutions from the Bretagnon model.  For SEC we intend a solution that only has secular terms in the eccentricity, \omega, inclination, \Omega of Saturn.  a is assumed constant.  In A21_SEC we take 21 terms for the variation in a of Saturn (only terms due to either Jupiter or Saturn), plus the secular terms, while in GI_SEC we took 8 terms for e and 6 for i associated with the great-inequality, but a constant.  Finally, in A_GI_SEC we combined everything together.   The following plots report
the results of our simulations for \sigma and the orbital elements according to the Bretagnon model.  Results in the table are multiplied by 10^-4.   In the third row we report the results of a \Chi-square test between the values of \sigma of the integration with Jupiter and Saturn, and the various Bretagnon solutions.  To compute \Chi-square we used the following method:  we subtracted the values of \sigma before the filtering from those after the filtering, and compute the relative standard deviation.  Then, if we call \sigma(1)_ij the filtered values of \sigma for the traditional simulation and \sigma(2)_ij the same for the Bretagnon one, we have:

\Chi-square=Sum(\sigma(1)_ij-\sigma(2)_ij)**2/(std1**2+std2**2)

The lower the value of \Chi-square, the better the fit.   The fourth Bretagnon simulation shows the best \Chi-square value.
 
SEC
A21_SEC
GI_SEC
A_GI_SEC
1.7+/-3.5 
1.4+/-3.3
1.4+/-2.6
 1.8+/-3.2
2741.6
132.3
70.7
33.5

SEC


A21-SEC


GI-SEC


A21-GI-SEC