Extension Commands¶

Extension commands are additional VARTOOLS commands that are compiled as separate shared-object libraries (.so files) and loaded at runtime. They are distributed in the USERLIBS/src subdirectory of the VARTOOLS source tree. After make install, the compiled extension libraries are placed in $(PREFIX)/share/vartools/USERLIBS/ and VARTOOLS finds them automatically, so the command flag (e.g. -magadd) can be used directly:

# Add a constant offset to each light curve before measuring the RMS.
vartools -l EXAMPLES/lc_list \
    -magadd fix 0.5 \
    -rms -tab

If you want to load an extension that has not been installed (or one that lives outside the installed search directory) you can pass it explicitly with -L, placed before the command flag:

vartools -L /path/to/mylib.so \
    -l EXAMPLES/lc_list \
    -mylib ... \
    -tab

The same -L flag can be given multiple times to load several extensions in a single call.

`-fastchi2`¶

Palmer's Fast χ² periodogram (Palmer 2009, ApJ, 695, 496).

Syntax

-fastchi2
    <"Nharm" <"fix" val | "list" | "fixcolumn" <colname | colnum>>
    <"freqmax" <"fix" val | "list" | "fixcolumn" <colname | colnum>>
    ["freqmin" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["detrendorder" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["t0" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["timespan" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["oversample" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["chimargin" <"fix" val | "list" | "fixcolumn" <colname | colnum>>]
    ["Npeak" val]
    ["norefitpeak"]
    ["oper" outdir ["nameformat" format]]
    ["omodel" outdir ["nameformat" format]]
    ["omodelvariable" varname]

Description

Compute the Fast χ² periodogram using Palmer's algorithm, which searches for the best-fitting multi-harmonic sinusoidal model at each trial frequency. Each parameter accepts one of three sources: "fix" (constant), "list" (input list), or "fixcolumn" (prior output column).

Python equivalent: fastchi2.

Parameters

Parameter	Description
`Nharm`	Number of harmonics in the model (1 = fundamental only, 2 = +first overtone, …).
`freqmax`	Maximum frequency searched, in cycles/day.
`freqmin`	Minimum frequency searched (default 0).
`detrendorder`	Order of polynomial detrend applied before the search (default 0).
`t0`	Reference epoch for detrending.
`timespan`	Total time span (used for the Nyquist frequency).
`oversample`	Oversampling factor for the periodogram grid.
`chimargin`	χ² margin for selecting periodogram peaks to refine.
`Npeak`	Number of peaks to report.
`"norefitpeak"`	Skip the refined peak search; emit raw periodogram peaks only.
`"oper" outdir`	Write the periodogram (suffix `.fastchi2.per`).
`"omodel" outdir`	Write the best-fit harmonic model.
`"omodelvariable" varname`	Store the model in a light-curve vector for use downstream.

Output columns: FastChi2_Period_<peak>_N, FastChi2_Chi2_<peak>_N, FastChi2_RChi2_<peak>_N.

References

Cite Palmer 2009, ApJ, 695, 496.

Examples

Example 1. Run Palmer's Fast χ² periodogram on EXAMPLES/2. Search frequencies from 0.1 to 10 cycles/day, fit one harmonic, and write the periodogram to EXAMPLES/OUTDIR1.

vartools -i EXAMPLES/2 -oneline -ascii \
    -fastchi2 Nharm fix 1 freqmax fix 10.0 \
        freqmin fix 0.1 oper EXAMPLES/OUTDIR1/

`-ftuneven`¶

Complex Fourier transform of unevenly sampled data (Scargle 1989, ApJ, 343, 874).

Syntax

-ftuneven
    <"outputvectors" freq_vec FTreal_vec FTimag_vec Pgram_vec |
     "outputfile" outdir ["nameformat" fmt] |
     "outputvectorsandfile" outdir ["nameformat" fmt]
                     freq_vec FTreal_vec FTimag_vec Pgram_vec>
    <"freqauto" |
     "freqrange" "minfreq" <...> "maxfreq" <...> "freqstep" <...> |
     "freqvariable" varname |
     "freqfile" filename>
    ["ft_sign" val] ["tt_zero" val]
    ["changeinputvectors" tvec data_real_vec data_imag_vec]

Description

Compute the complex Fourier transform of an unevenly sampled time series using Scargle's method. Returns the real and imaginary components plus the absolute-square power spectrum (equivalent to the Lomb-Scargle periodogram). Input and output frequencies are in radians per unit time.

Python equivalent: ftuneven.

Parameters

Output mode (choose one):

Mode	Description
`"outputvectors" freq_vec FTreal_vec FTimag_vec Pgram_vec`	Store results in named LC vectors for downstream commands. All LC vectors are resized to the transform length.
`"outputfile" outdir`	Write per-LC files (default name `BASELC.ftuneven`; four whitespace columns: freq, FT_real, FT_imag, periodogram).
`"outputvectorsandfile" outdir ... freq_vec ...`	Do both simultaneously.

Frequency source (choose one):

Mode	Description
`"freqauto"`	Determine frequencies automatically from the time baseline and cadence.
`"freqrange" minfreq maxfreq freqstep`	Uniform grid.
`"freqvariable" varname`	Read frequencies from an existing LC vector.
`"freqfile" filename`	Read frequencies from the first column of an ASCII file (used identically for every LC).

Keyword	Description
`"ft_sign" val`	Sign of the transform: `−1` (default) = forward; `+1` = inverse.
`"tt_zero" val`	Time origin (default 0).
`"changeinputvectors" tvec data_real_vec data_imag_vec`	Apply the transform to vectors other than `t`/`mag`.

References

Cite Scargle 1989, ApJ, 343, 874.

Examples

Example 1. Compute Scargle's complex Fourier transform of EXAMPLES/2 over a uniform grid from 0.05 to 5.0 (radians/unit time), step 0.001. The transform is written to EXAMPLES/OUTDIR1/2.ftuneven with four whitespace columns: frequency (rad/time), real component, imaginary component, and the absolute-square (≡ Lomb-Scargle periodogram).

vartools -i EXAMPLES/2 -oneline \
    -ftuneven outputfile EXAMPLES/OUTDIR1 \
        freqrange minfreq fix 0.05 maxfreq fix 5.0 \
        freqstep fix 0.001

To make the transform available to subsequent commands rather than writing a file, replace outputfile with outputvectors freq ftreal ftimag pgram (giving names for the four output LC vectors); outputvectorsandfile does both.

`-hatpiflag`¶

Binary flag generator for HATPI light curves.

Syntax

-hatpiflag
    fiphot_string_flag_var rejbadframe_mask_var TFA_outlier_mask_var
    pointing_outlier_flag_var output_flag_var

Description

Combine several per-point quality indicators into a single bit-packed flag variable suitable for HATPI photometry pipelines. Each input contributes a different bit to the output:

bits 0–3 (values 1, 2, 4, 8): set from the fiphot string flag — X (bad photometry) sets bit 0, C (saturated/hot) sets bit 1, A (asteroid) sets bit 2, S (satellite) sets bit 3 (H/I/J/K set combinations of bits 1–3).
bit 4 (value 16): set when the bad-frame mask flags the point as rejected.
bit 5 (value 32): set when the TFA-outlier mask flags the point as an outlier.
bit 6 (value 64): set when the pointing-outlier flag is 1.

Python equivalent: hatpiflag.

Parameters

Argument	Description
`fiphot_string_flag_var`	Vector of one-character string flags from fiphot.
`rejbadframe_mask_var`	Bad-frame mask (0 = rejected, 1 = keep).
`TFA_outlier_mask_var`	TFA outlier mask (0 = outlier, 1 = keep).
`pointing_outlier_flag_var`	Pointing outlier flag (1 = outlier, 0 = ok).
`output_flag_var`	Name of the LC vector to receive the combined binary flag.

Examples

Example 1. Combine the four HATPI per-observation quality vectors stored in EXAMPLES/2.hatpiflag into a single bit-packed flag. The file has the standard t/mag/err columns followed by the four extra columns (one-character fiphot string flag, reject-bad-frame mask, TFA-outlier mask, pointing-outlier flag). -inputlcformat reads the four flag columns under their named variables; -hatpiflag combines them into quality_flag. The -stats call reports summary statistics of the result.

vartools -i EXAMPLES/2.hatpiflag \
    -inputlcformat 't:1,mag:2,err:3,fiphot_flag:4:string,rejbadframe:5,tfa_mask:6,pointing_outlier:7' \
    -hatpiflag fiphot_flag rejbadframe tfa_mask pointing_outlier quality_flag \
    -stats quality_flag mean,sum,max -oneline

`-jktebop`¶

JKTEBOP detached eclipsing binary light curve model.

Syntax

-jktebop
    < "inject" | "fit" >
    <"Period"   <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"T0"       <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"r1+r2"    <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"r2/r1"    <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"M2/M1"    <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"J2/J1"    <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <<"i" | "bimpact"> <"fix" value | ...> ["vary"]>
    <"esinomega" <...> ["vary"]>
    <"ecosomega" <...> ["vary"]>
    <"LD1" <"linear"|"quad"|"log"|"sqrt"> <"fix" value1 [value2] | ...> ["vary"]>
    <"LD2" <"lockLD1"|"linear"|"quad"|"log"|"sqrt"> [...] ["vary"]>
    ["gravdark1" <...> ["vary"]]  ["gravdark2" <...> ["vary"]]
    ["reflection1" <...> ["vary"]] ["reflection2" <...> ["vary"]]
    ["L3" <...> ["vary"]] ["tidallag" <...> ["vary"]]
    ["correctlc"]
    ["omodel" <outdir ["format" fmt]>]
    ["ocurve" <"jd" | "phase"> ["step" stepsize] <"outdir" outdir ["format" fmt]>]

Description

Fit or inject a JKTEBOP detached eclipsing-binary light-curve model. Use "inject" to add the model to the light curve, or "fit" to optimise the parameters. Append "vary" to any parameter to allow it to vary during fitting.

Python equivalent: jktebop.

Parameters

Geometric parameters:

Parameter	Description
`Period`	Orbital period in days.
`T0`	Central time of a primary eclipse.
`r1+r2`	Sum of stellar radii divided by the semi-major axis.
`r2/r1`	Ratio of stellar radii.
`M2/M1`	Mass ratio.
`J2/J1`	Surface brightness ratio.
`i`	Orbital inclination in degrees (90° = edge-on).
`bimpact`	Impact parameter at primary eclipse (alternative to `i`; 0 = central, 1 = grazing).
`esinomega`	e sin ω.
`ecosomega`	e cos ω.

Limb darkening — LD1, LD2: pick a law ("linear", "quad", "log", "sqrt") and supply 1 or 2 coefficients as required. LD2 lockLD1 forces the secondary to share the primary's coefficients.

Optional physical parameters: gravdark1/2 (gravity darkening, default 1.0), reflection1/2 (reflection coefficients, computed if absent or ≤ 0), L3 (third light, default 0), tidallag (tidal lag in degrees, default 0).

Output flag	Description
`"correctlc"`	Subtract the best-fit model from the LC.
`"omodel" outdir`	Write the model evaluated at the observed times (suffix `.jktebop.model`).
`"ocurve"`	Write a uniformly sampled model curve in `"jd"` or `"phase"`. `"step"` sets the grid spacing.

References

Cite Southworth et al. 2004, MNRAS, 351, 1277; Popper & Etzel 1981, AJ, 86, 102; Etzel 1981, Photometric and Spectroscopic Binary Systems, 111; Nelson & Davis 1972, ApJ, 174, 617.

Examples

Example 1. Inject a JKTEBOP detached eclipsing-binary signal into EXAMPLES/3 and recover the primary eclipse with -BLS. The injected system has a 2.5-day period, T0 = 53727.0, sum of fractional radii (R1+R2)/a = 0.15, radius ratio R2/R1 = 0.5, mass ratio M2/M1 = 0.6, surface-brightness ratio J2/J1 = 0.3, inclination 89°, and a circular orbit. Both stars use a quadratic limb-darkening law with coefficients (0.3, 0.3); LD2 is locked to LD1. The injected model is written to EXAMPLES/OUTDIR1/3.jktebop.model.

vartools -i EXAMPLES/3 -oneline \
    -jktebop inject \
        Period fix 2.5 \
        T0 fix 53727.0 \
        r1+r2 fix 0.15 \
        r2/r1 fix 0.5 \
        M2/M1 fix 0.6 \
        J2/J1 fix 0.3 \
        i fix 89.0 \
        esinomega fix 0.0 \
        ecosomega fix 0.0 \
        LD1 quad fix 0.3 0.3 \
        LD2 lockLD1 \
        omodel EXAMPLES/OUTDIR1/ \
    -BLS q 0.01 0.1 1.0 5.0 5000 200 7 1 0 0 0

`-splinedetrend`¶

Multivariate light curve detrending using linear basis functions.

Syntax

-splinedetrend
    detrendvec1:<"spline":knotspacing:order |
                 "poly":order |
                 "harm":nharm>[:"groupbygap":gapsize]
    [,detrendvec2:<...>[:"groupbygap":gapsize],...]
    ["sigmaclip" <"fix" val | "list" | "fixcolumn" <colname|colnum> | "expr" expr>]
    ["omodel" outdir ["nameformat" format]]
    ["omodelcoeffs" outdir ["nameformat" format]]
    ["omodelvariable" outvarname1[:inputvarsignal1][,...]]

Description

Fit a multivariate linear model to the light-curve magnitudes against one or more auxiliary variables (e.g. time, CCD x/y position, CCD temperature). Cross-terms between variables are not included.

Python equivalent: splinedetrend.

Parameters

The first argument is a comma-separated list of detrendvec:basistype tokens. Three basis types are supported:

Basis	Parameters	Description
`"spline"`	`knotspacing`, `order`	B-spline basis (GSL `gsl_bspline_eval`). `knotspacing` in the same units as the variable; `order` = 3 for cubic.
`"poly"`	`order`	Polynomial; `order` = 1 for linear, 2 for quadratic, etc.
`"harm"`	`nharm`	Harmonic series; `nharm` = 0 for fundamental only (period = 2× variable range).

Append :"groupbygap":gapsize to split the fit at gaps in the detrending variable larger than gapsize.

Keyword	Description
`"sigmaclip"`	Exclude outliers above this σ threshold from the fit. The model is still evaluated and subtracted at clipped points.
`"omodel" outdir`	Write the best-fit model (suffix `.splinedetrend_model`).
`"omodelcoeffs" outdir`	Write the linear basis coefficients (suffix `.splinedetrend_modelcoeffs`).
`"omodelvariable" outvar1[:invar1],...`	Store the per-variable model contribution(s) in named output LC vectors.

Output columns: Splinedetrend_MedianMagnitude_N, Splinedetrend_NOutliers_N, Splinedetrend_NDataGroups_N, Splinedetrend_NFitParamsTotal_N.

Examples

Example 1. Detrend a TESS sector-1 light curve for GAIA DR2 6479535620075955328. We read the time, magnitude, uncertainty, x/y pixel positions and CCD temperature from the FITS file, save the original magnitude as magorig, then detrend simultaneously against t (cubic B-spline with 1.0-day knot spacing, split into time-groups at gaps larger than 0.5 days), and x, y, temp (linear polynomial each). 3σ outliers are excluded from the fit. The model and the linear coefficients are written to EXAMPLES/OUTDIR1, and the per-variable model contributions are stored in tmod, xmod, ymod, tempmod. The detrended LC plus all auxiliary columns are written for inspection.

vartools -i EXAMPLES/6479535620075955328_llc.fits \
    -inputlcformat \
        t:TMID_BJD,mag:IRM1,err:IRE1,x:XIC,y:YIC,temp:CCDTEMP \
    -expr magorig=mag \
    -splinedetrend \
        t:spline:1.0:3:groupbygap:0.5,x:poly:1,y:poly:1,temp:poly:1 \
        sigmaclip fix 3.0 \
        omodel EXAMPLES/OUTDIR1/ \
        omodelcoeffs EXAMPLES/OUTDIR1/ \
        omodelvariable \
            tmod:t,xmod:x,ymod:y,tempmod:temp \
    -o EXAMPLES/OUTDIR1/6479535620075955328.splinedetrend.lc.txt \
        columnformat t,magorig,mag,err,x,y,temp,tmod,xmod,ymod,tempmod \
    -rms -oneline

Name                            = ./6479535620075955328_llc.fits
Splinedetrend_MedianMagnitude_1 = 10.33609
Splinedetrend_NOutliers_1       = 0
Splinedetrend_NDataGroups_1     = 3
Splinedetrend_NFitParamsTotal_1 = 44
Mean_Mag_3                      =  10.33609
RMS_3                           =   0.00137
Expected_RMS_3                  =   0.00566
Npoints_3                       =  1149

The four splinedetrend output columns report the median magnitude (which is added back to the detrended LC), the number of clipped outliers, the number of fit groups created by groupbygap, and the total free-parameter count of the model.

`-stitch`¶

Fit and remove zero-point offsets between combined light curve segments.

Syntax

-stitch
    stitch_variable_list uncertainty_variable_list
    mask_variable_list lcnum_var
    ["refnum_var" refnum_var]
    <"median" | "mean" | "weightedmean" | "poly" order |
     "harmseries" period_var Nharm>
    ["groupbytime" time_bin ["start" firstbintime]]
    ["fitonly"]
    ["save_fitted_parameters" <outdir ["format" fmt]>]
    ...

Description

Designed for use with the -l "combinelcs" (or -i "combinelcs") input mode, -stitch fits for and removes additive offsets between distinct light-curve segments (e.g. observations from different telescopes, cameras, or fields).

Python equivalent: stitch.

Parameters

Required arguments:

Argument	Description
`stitch_variable_list`	Comma-separated list of magnitude variables to stitch (typically just `mag`).
`uncertainty_variable_list`	Comma-separated uncertainties for each magnitude variable (typically `err`).
`mask_variable_list`	Comma-separated mask vectors; points with `mask = 0` are excluded from the fit (1 = include).
`lcnum_var`	Variable identifying which input segment each observation belongs to (typically set by the `lcnumvar` keyword of `combinelcs`).

Fitting method (choose one):

Method	Description
`"median"`	Per-segment medians; solve for additive offsets.
`"mean"`	Per-segment means.
`"weightedmean"`	Inverse-variance weighted means.
`"poly" order`	Fit a polynomial of the given order in time per segment.
`"harmseries" period_var Nharm`	Fit a harmonic series; period taken from `period_var`, with `Nharm` harmonics.

Optional keywords:

Keyword	Description
`"refnum_var" varname`	Further subdivide segments by a second grouping variable.
`"groupbytime" time_bin`	Group segments into time bins; the bin size is automatically widened if necessary so all segments can be inter-calibrated.
`"fitonly"`	Compute the shifts but do not subtract them.
`"save_fitted_parameters" outdir`	Write per-source shift files (suffix `.stitch`).
`"shifts_file" ...`	Read previously determined shifts and/or write new ones for incremental re-processing of large datasets.

Output columns: Stitch_NLCGroups_N, Stitch_NTimeGroups_N, Stitch_NFitParamsTotal_N.

Examples

Example 1. Combine two LC segments — EXAMPLES/2 and EXAMPLES/2.shifted (which is EXAMPLES/2 with +0.3 mag added) — into a single in-memory light curve using combinelcs, then fit and remove the inter-segment offset with -stitch. The list file EXAMPLES/lc_list_stitch contains the comma-separated pair of file names; lcnumvar lcnum stores the segment index (0 or 1) per point in the variable lcnum, which -stitch needs to identify which points belong to which segment. -expr creates a per-point mask that is uniformly 1 (no points masked); a real application would derive mask from quality flags. The two -rms calls show that before stitching the combined LC has an inflated RMS due to the offset, and after stitching the RMS returns to the original EXAMPLES/2 value.

vartools -l EXAMPLES/lc_list_stitch combinelcs lcnumvar lcnum \
    -expr 'mask=mag*0+1' \
    -rms \
    -stitch mag err mask lcnum median \
    -rms -oneline

`-macula`¶

Kipping's Macula analytic starspot model (Kipping 2012, arXiv:1209.2985).

Syntax

-macula
    <"inject" | "fit" <"amoeba" | "lm">>
    <"Prot"   <"fix" value | "list" | "fixcolumn" <colname|colnum>> ["vary"]>
    <"istar"  <...> ["vary"]>
    <"kappa2" <...> ["vary"]>  <"kappa4" <...> ["vary"]>
    <"c1" <...> ["vary"]>  <"c2" <...> ["vary"]>
    <"c3" <...> ["vary"]>  <"c4" <...> ["vary"]>
    <"d1" <...> ["vary"]>  <"d2" <...> ["vary"]>
    <"d3" <...> ["vary"]>  <"d4" <...> ["vary"]>
    <"blend" <...> ["vary"]>
    <"Nspot" value>
        <"Lambda0" <...> ["vary"]>  <"Phi0" <...> ["vary"]>
        <"alphamax" <...> ["vary"]> <"fspot" <...> ["vary"]>
        <"tmax" <...> ["vary"]>     <"life" <...> ["vary"]>
        <"ingress" <...> ["vary"]>  <"egress" <...> ["vary"]>
        ... (repeat Nspot times) ...
    ["fluxinput"] ["fluxoutput"] ["correctlc"]
    ["omodel" <outdir ["nameformat" fmt]> ["tdelv"]]
    ["ocurve" <"outdir" outdir ["nameformat" fmt]> ["tdelv"] ["step" stepsize]]

Description

Fit or inject Kipping's Macula analytic model for starspot modulation. Use "inject" to add the model signal to the light curve, or "fit" with "amoeba" (Nelder-Mead simplex) or "lm" (Levenberg-Marquardt) to optimise the parameters. Append "vary" to any parameter to mark it as free during fitting.

Python equivalent: macula.

Parameters

Stellar parameters:

Parameter	Description
`Prot`	Equatorial rotation period (LC time units).
`istar`	Stellar inclination (radians).
`kappa2`, `kappa4`	Quadratic / quartic differential-rotation coefficients.
`c1`–`c4`	Four-coefficient stellar limb-darkening terms.
`d1`–`d4`	Four-coefficient spot limb-darkening terms.
`blend`	Blend parameter.

Per-spot parameters (repeated Nspot times):

Parameter	Description
`Lambda0`	Longitude at maximum spot size (radians).
`Phi0`	Latitude at maximum spot size (radians).
`alphamax`	Maximum angular radius (radians).
`fspot`	Spot-to-star flux contrast.
`tmax`	Reference epoch of maximum spot size.
`life`	Spot lifetime, FWHM (LC time units).
`ingress`	Spot growth duration.
`egress`	Spot decay duration.

Output / control flags:

Flag	Description
`"fluxinput"` / `"fluxoutput"`	Toggle flux vs. magnitude input/output (default: magnitudes).
`"correctlc"`	Subtract the model from the LC.
`"omodel" outdir`	Write the model evaluated at the observed times (suffix `.macula.model`). Add `"tdelv"` to include predicted transit-depth variations.
`"ocurve" outdir`	Write the model on a uniformly sampled time grid for plotting. `"step"` controls the grid spacing.

References

Cite Kipping 2012, arXiv:1209.2985.

Examples

Example 1. Simulate the light curve of a single-spotted star using Macula. We read EXAMPLES/3 for its time sampling and uncertainties, replace the magnitudes with Gaussian noise (mag = 10 + err·gauss()), and inject one spot with all stellar and spot parameters fixed except tmax, which we set to the minimum time of the LC (computed by the prior -stats). The simulated LC is written to EXAMPLES/OUTDIR1/3.maculainject.

vartools -i EXAMPLES/3 \
    -stats t min \
    -expr 'mag=10.0+err*gauss()' \
    -macula inject \
        Prot fix 1.234567 \
        istar fix 1.4567 \
        kappa2 fix 0.0 \
        kappa4 fix 0.0 \
        c1 fix 0.2 c2 fix 0.1 c3 fix 0.0 c4 fix 0.0 \
        d1 fix 0.2 d2 fix 0.1 d3 fix 0.0 d4 fix 0.0 \
        blend fix 1.0 \
        Nspot 1 \
            Lambda0 fix 0.0 \
            Phi0 fix 1.2345 \
            alphamax fix 0.2 \
            fspot fix 0.1 \
            tmax fixcolumn STATS_t_MIN_0 \
            life fix 1000.0 \
            ingress fix 0.1 \
            egress fix 0.1 \
    -o EXAMPLES/OUTDIR1/3.maculainject \
    -oneline

Example 2. Fit the Macula model to the simulated LC from Example 1 with the downhill-simplex optimiser. -LS first finds the rotation period, which then seeds Prot. Only Prot and istar are marked vary; the other parameters are held at their initial values. The fit is evaluated both at the observed times (omodel) and on a uniform grid for plotting (ocurve).

vartools -i EXAMPLES/OUTDIR1/3.maculainject \
    -stats t min \
    -LS 0.1 100 0.1 1 0 \
    -macula fit amoeba \
        Prot fixcolumn LS_Period_1_1 vary \
        istar fix 1.6 vary \
        kappa2 fix 0.0 \
        kappa4 fix 0.0 \
        c1 fix 0.2 c2 fix 0.1 c3 fix 0.0 c4 fix 0.0 \
        d1 fix 0.2 d2 fix 0.1 d3 fix 0.0 d4 fix 0.0 \
        blend fix 1.0 \
        Nspot 1 \
            Lambda0 fix 0.0 \
            Phi0 fix 1.2345 \
            alphamax fix 0.2 \
            fspot fix 0.1 \
            tmax fixcolumn STATS_t_MIN_0 \
            life fix 1000.0 \
            ingress fix 0.1 \
            egress fix 0.1 \
        omodel EXAMPLES/OUTDIR1 \
        ocurve EXAMPLES/OUTDIR1 \
    -oneline

The injected light curve from Example 1 with the Example 2 fitted-model curve overplotted:

Macula injected vs fitted model

`-magadd`¶

Add a constant offset to light curve magnitudes.

Syntax

-magadd
    <"fix" value | "list" ["column" col] | "fixcolumn" <colname | colnum> | "expr" expr>

Description

Add a scalar offset to every magnitude in the light curve. The offset can be a fixed constant, a per-LC value from the input list, a previously computed output statistic, or an analytic expression. This is also the canonical template extension included in the source tree to demonstrate how to write user-defined VARTOOLS extensions.

Python equivalent: magadd.

Parameters

Source keyword	Description
`"fix" value`	Add the same constant to all light curves.
`"list" ["column" col]`	Read the offset per LC from the input list.
`"fixcolumn" col`	Take the offset from a previously computed output statistic.
`"expr" expr`	Evaluate an analytic expression per LC.

Output columns: Magadd_addval_N (the value applied for that LC).

Examples

Example 1. Add a constant 0.5 mag to every observation of EXAMPLES/2. The two -rms calls before and after -magadd show that the mean magnitude shifts by 0.5 while the RMS is unchanged.

vartools -i EXAMPLES/2 -oneline \
    -rms \
    -magadd fix 0.5 \
    -rms

Extension Commands¶

-fastchi2¶

-ftuneven¶

-hatpiflag¶

-jktebop¶

-splinedetrend¶

-stitch¶

-macula¶

-magadd¶

`-fastchi2`¶

`-ftuneven`¶

`-hatpiflag`¶

`-jktebop`¶

`-splinedetrend`¶

`-stitch`¶

`-macula`¶

`-magadd`¶