CTest: astronomical parameters from interpreted spectral peaks

Usage

ctest(
  data,
  nsim = 1000,
  mode = c("PT", "P", "T"),
  ptest = c(10000, 28000),
  sampleorb = c("U", "N"),
  seed = NULL,
  max_attempts = 5e+07,
  verbose = TRUE,
  engine = c("vectorized", "loop"),
  block = 1e+05,
  s3_uncertainty = c("published", "scaled")
)

Arguments

data: Interpreted spectral peaks as an 8 x 2 table (matrix, data frame or tibble), in the layout of the published spreadsheet, best built with ctest_input: row 1 the age range of the record in Ma (min, max); rows 2 to 8 the frequency ranges in cycles per metre of the 405-kyr, ~125-kyr and ~95-kyr eccentricity cycles, the obliquity cycle (k+s3) and the three precession cycles (k+g5; k+g2; k+g4 and k+g3), with the lower frequency (longer wavelength) in column 1 and the higher frequency in column 2. The obliquity row may be NA when mode="P" and the precession rows when mode="T". Required, no default.
nsim: Number of accepted (successful) samples to collect (integer, > 0). Default=1000.
mode: Which cycles constrain the precession constant besides eccentricity (character): "PT" precession and obliquity (tilt), "P" precession only, "T" obliquity only. Default=c("PT", "P", "T"), i.e. "PT".
ptest: Range of the precession constant that is sampled (uniformly), given as its period in years (numeric vector c(min, max)). Default=c(10000, 28000).
sampleorb: Distribution from which the secular frequencies g2, g3, g4 and g5 are drawn around their Laskar et al. (2011) values, with an uncertainty that grows with the square root of age (character): "U" uniform within 2 sigma (used in the paper) or "N" normal. Default=c("U", "N"), i.e. "U".
seed: Seed of the random number generator (integer), so that the samples can be reproduced; NULL leaves the current random state unchanged. Default=NULL.
max_attempts: Maximum number of draws (numeric); the function stops with an error if fewer than nsim samples have been accepted by then, which usually means the interpreted cycle ranges are inconsistent. Default=5e7.
verbose: Print progress messages with the number of accepted samples and the acceptance rate (logical, TRUE or FALSE). Default=TRUE.
engine: Sampling engine (character): "vectorized" draws in blocks of block samples (fast); "loop" draws one sample at a time in the published draw order and reproduces mmc3/mmc4/mmc5 sample for sample under the same seed. Default=c("vectorized", "loop"), i.e. "vectorized".
block: Number of draws per block for engine="vectorized" (integer; limited to 1000 to 5e6); larger blocks are faster but use more memory. Ignored by engine="loop". Default=1e5.
s3_uncertainty: How the uncertainty of the secular frequency s3 (used for obliquity) is applied (character): "published" keeps the draw of the published code, rnorm(1, s3, ds3 * sqrt(t / 1e8)), in which the relative uncertainty ds3 is applied as an absolute one in years, so s3 is effectively fixed (use this to reproduce the paper); "scaled" applies it as for g2 to g5 (s3 * ds3 * sqrt(t / 1e8)), which gives s3 a realistic spread. Default=c("published", "scaled"), i.e. "published".

Value

list with `summary` (table as in the paper), `samples` (all accepted samples), `sampled_range` of g/s, and `acceptance`