# Cesium Features - By Category¶

all_times_nhist_numpeaks Number of peaks (local maxima) in histogram of all possible delta_t’s.
all_times_nhist_peak1_bin Return the (bin) index of the ith largest peak. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak2_bin Return the (bin) index of the ith largest peak. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak3_bin Return the (bin) index of the ith largest peak. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak4_bin Return the (bin) index of the ith largest peak. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_1_to_2 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_1_to_3 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_1_to_4 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_2_to_3 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_2_to_4 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_3_to_4 Compute the ratio of the values of the ith and jth largest peaks. Peaks is a list of tuples (i, x[i]) of peak indices i and values x[i], sorted in decreasing order by peak value.
all_times_nhist_peak_val Peak value in histogram of all possible delta_t’s.
avg_double_to_single_step Mean value of ratios (t[i+2] - t[i]) / (t[i+2] - t[i+1]).
avg_err Mean of the error estimates.
avgt Mean of the time values.
cad_probs_1 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_10 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_20 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_30 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_40 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_50 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_100 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_500 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_1000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_5000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_10000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_50000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_100000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_500000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_1000000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_5000000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
cad_probs_10000000 Given the observed distribution of time lags cads, compute the probability that the next observation occurs within time minutes of an arbitrary epoch.
mean Mean of observed values.
med_double_to_single_step Median value of ratios (t[i+2] - t[i]) / (t[i+2] - t[i+1]).
med_err Median of error estimates.
n_epochs Total number of observed values.
std_double_to_single_step Standard deviation of ratios (t[i+2] - t[i]) / (t[i+2] - t[i+1]).
std_err Standard deviation of the error estimates.
total_time Absolute difference between max and min of time values.
General Description
amplitude Half the difference between the maximum and minimum magnitude.
flux_percentile_ratio_mid20 A ratio of ((50+x) flux percentile - (50-x) flux percentile) / (95 flux percentile - 5 flux percentile), where x = percentile_range/2.
flux_percentile_ratio_mid35 A ratio of ((50+x) flux percentile - (50-x) flux percentile) / (95 flux percentile - 5 flux percentile), where x = percentile_range/2.
flux_percentile_ratio_mid50 A ratio of ((50+x) flux percentile - (50-x) flux percentile) / (95 flux percentile - 5 flux percentile), where x = percentile_range/2.
flux_percentile_ratio_mid65 A ratio of ((50+x) flux percentile - (50-x) flux percentile) / (95 flux percentile - 5 flux percentile), where x = percentile_range/2.
flux_percentile_ratio_mid80 A ratio of ((50+x) flux percentile - (50-x) flux percentile) / (95 flux percentile - 5 flux percentile), where x = percentile_range/2.
max_slope Compute the largest rate of change in the observed data.
maximum Maximum observed value.
median Median of observed values.
median_absolute_deviation Median absolute deviation (from the median) of the observed values.
minimum Minimum observed value.
percent_amplitude Returns the largest distance from the median value, measured as a percentage of the median.
percent_beyond_1_std Percentage of values more than 1 std. dev. from the weighted average.
percent_close_to_median Percentage of values within window_frac*(max(x)-min(x)) of median.
percent_difference_flux_percentile Difference between the 95th and 5th percentiles of the data, expressed as a percentage of the median value. See Eyer (2005) arXiv:astro-ph/0511458v1, Evans & Belokurov (2005) (there the 98th and 2nd percentiles are used).
period_fast Fits a simple sinuosidal model
qso_log_chi2_qsonu Natural log of goodness of fit of qso-model given fixed parameters.
qso_log_chi2nuNULL_chi2nu Natural log of expected chi2/nu for non-qso variable.
skew Skewness of a dataset. Approximately 0 for Gaussian data.
std Standard deviation of observed values.
stetson_j Robust covariance statistic between pairs of observations x,y whose uncertainties are dx,dy. If y is not given, calculates a robust variance for x.
stetson_k A robust kurtosis statistic.
weighted_average Arithmetic mean of observed values, weighted by measurement errors.
Lomb-Scargle (Periodic) Description
fold2P_slope_10percentile Get alphath percentile of slopes of period-folded model.
fold2P_slope_90percentile Get alphath percentile of slopes of period-folded model.
freq1_amplitude1 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_amplitude2 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_amplitude3 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_amplitude4 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_freq Get the ith frequency from a fitted Lomb-Scargle model.
freq1_lambda Get the regularization parameter of a fitted Lomb-Scargle model.
freq1_rel_phase2 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_rel_phase3 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_rel_phase4 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq1_signif Get the significance (in sigmas) of the first frequency from a fitted Lomb-Scargle model.
freq2_amplitude1 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_amplitude2 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_amplitude3 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_amplitude4 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_freq Get the ith frequency from a fitted Lomb-Scargle model.
freq2_rel_phase2 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_rel_phase3 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq2_rel_phase4 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_amplitude1 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_amplitude2 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_amplitude3 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_amplitude4 Get the amplitude of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_freq Get the ith frequency from a fitted Lomb-Scargle model.
freq3_rel_phase2 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_rel_phase3 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq3_rel_phase4 Get the relative phase of the jth harmonic of the ith frequency from a fitted Lomb-Scargle model.
freq_amplitude_ratio_21 Get the ratio of the amplitudes of the first harmonic for the ith and first frequencies from a fitted Lomb-Scargle model.
freq_amplitude_ratio_31 Get the ratio of the amplitudes of the first harmonic for the ith and first frequencies from a fitted Lomb-Scargle model.
freq_frequency_ratio_21 Get the ratio of the ith and first frequencies from a fitted Lomb-Scargle model.
freq_frequency_ratio_31 Get the ratio of the ith and first frequencies from a fitted Lomb-Scargle model.
freq_model_max_delta_mags Largest value minus second largest value of fitted Lomb Scargle model.
freq_model_min_delta_mags Second smallest value minus smallest value of fitted Lomb Scargle model.
freq_model_phi1_phi2 Ratio of distances between the second minimum and first maximum, and the second minimum and second maximum, of the fitted Lomb-Scargle model.
freq_n_alias Here we check for “1-day” aliases in ASAS / Deboss sources.
freq_signif_ratio_21 Get the ratio of the significances (in sigmas) of the ith and first frequencies from a fitted Lomb-Scargle model.
freq_signif_ratio_31 Get the ratio of the significances (in sigmas) of the ith and first frequencies from a fitted Lomb-Scargle model.
freq_varrat Get the fraction of the variance explained by the first frequency of a fitted Lomb-Scargle model.
freq_y_offset Get the y-intercept of a fitted Lomb-Scargle model.
linear_trend Get the linear trend of a fitted Lomb-Scargle model.
medperc90_2p_p Get ratio of 90th percentiles of residuals for data folded by twice the estimated period and the estimated period, respectively.
p2p_scatter_2praw Get ratio of variability (sum of squared differences of consecutive values) of folded and unfolded models.
p2p_scatter_over_mad Get ratio of variability of folded and unfolded models.
p2p_scatter_pfold_over_mad Get ratio of median of period-folded data over median absolute deviation of observed values.
p2p_ssqr_diff_over_var Get sum of squared differences of consecutive values as a fraction of the variance of the data.
scatter_res_raw From arXiv 1101_2406v1 Dubath 20110112 paper.