Syntax:

-decorr correctlc zeropointterm subtractfirstterm Nglobalterms globalfile1 order1 ... Nlcterms lccolumn1 lcorder1 ... omodel [model_outdir]

Example 1.
$ ./vartools -l EXAMPLES/lc_list -header \
    -rms \
    -decorr 1 1 1 0 1 1 2 0 \
    -rms

#Name Mean_Mag_0 RMS_0 Expected_RMS_0 Npoints_0 Decorr_constant_term_1 Decorr_constant_term_err_1 LCColumn_1_coeff_1_1 LCColumn_1_coeff_err_1_1 \
    LCColumn_1_coeff_2_1 LCColumn_1_coeff_err_2_1 Decorr_chi2_1 Mean_Mag_2 RMS_2 Expected_RMS_2 Npoints_2
EXAMPLES/1  10.24745   0.15944   0.00101  3122     10.0830375984825      0.0000325849746      0.0097933162509      0.0097933162509 \
    0.0002554062775      0.0002554062775      6.68601  10.24728   0.00211   0.00101  3122
EXAMPLES/2  10.11802   0.03663   0.00102  3313     10.1089753109696      0.0000321843725      0.0003489758977      0.0003489758977 \
    -0.0000050541834     -0.0000050541834   1755.64028  10.12417   0.03657   0.00102  3313
EXAMPLES/3  10.16674   0.00490   0.00104  3417     10.1659431955329      0.0000324178381      0.0000836121707      0.0000836121707 \
    -0.0000001270601     -0.0000001270601     26.40822  10.16662   0.00485   0.00104  3417
EXAMPLES/4  10.35142   0.00209   0.00114  3227     10.3504285453973      0.0000364204458      0.0001938021136      0.0001938021136 \
    -0.0000058852944     -0.0000058852944      4.92236  10.35144   0.00205   0.00114  3227
EXAMPLES/5  10.43962   0.00288   0.00114  3903     10.4381409961476      0.0000333590373      0.0001754549866      0.0001754549866 \
    -0.0000036936281     -0.0000036936281      7.82090  10.43987   0.00285   0.00114  3903
EXAMPLES/6  10.52762   0.00209   0.00121  3933     10.5268081102353      0.0000351765599      0.0001431023590      0.0001431023590 \
    -0.0000043442275     -0.0000043442275      3.83110  10.52772   0.00206   0.00121  3933
EXAMPLES/7  10.56966   0.00349   0.00116  3626     10.5695886705431      0.0000361386139      0.0000047832341      0.0000047832341 \
    -0.0000006353454     -0.0000006353454     10.40848  10.56981   0.00348   0.00116  3626
EXAMPLES/8  10.61152   0.00225   0.00125  3957     10.6116126344903      0.0000363856952     -0.0001259754440     -0.0001259754440 \
    0.0000051862416      0.0000051862416      4.06144  10.61174   0.00221   0.00125  3957
EXAMPLES/9  10.73139   0.00187   0.00133  3954     10.7308002296744      0.0000386306851      0.0000885383168      0.0000885383168 \
    -0.0000023248367     -0.0000023248367      2.62157  10.73147   0.00186   0.00133  3954
EXAMPLES/10  10.87781   0.00236   0.00143  3974     10.8767761937821      0.0000414614974      0.0001687838294      0.0001687838294 \
    -0.0000048171315     -0.0000048171315      3.59696  10.87794   0.00233   0.00143  3974

Fit a quadratic polynomial to the light curves given in the file EXAMPLES/lc_list. To do this we use no global terms and 1 lc term. For the lc term we use the first column in the light curve (the JD) and fit a second order polynomial in this term to each light curve. We fit for the zero-point term and correct the light curve (so that commands after -decorr will receive light curves with the best-fit quadratic polynomial removed, note that when the light curve is corrected the mean is kept constant), we also subtract the first term in the signal that we are decorrelating against (use JD - JD0 rather than JD, since JD*JD runs into round-off problems whereas (JD - JD0)*(JD - JD0) does not), but we do not output the corrected light curves to the disk. The rms is determined before and after the fit. To interpret the output, note that for light curve 1 we find that the best-fit quadratic has the form: 0.0002554062775*(JD - 53725.173920)*(JD - 53725.173920) + 0.0097933162509*(JD - 53725.173920) + 10.0830375984825, and that fitting this equation reduces the RMS from 0.15944 mag to 0.00211 mag (a quadratic signal was injected into this particular light curve).