space_removed: Space Removal Diagnostics

In hmer: History Matching and Emulation Package

Space Removal Diagnostics

Description

Finds the proportion of space removed as a function of implausibility cut-off and of one of structural discrepancy, emulator variance, or correlation hyperparameter(s).

Usage

space_removed(
  ems,
  targets,
  ppd = 10,
  u_mod = seq(0.8, 1.2, by = 0.1),
  intervals = seq(0, 10, length.out = 200),
  modified = "obs",
  maxpoints = 50000
)

Arguments

ems	The Emulator objects.
targets	The corresponding targets to match to.
ppd	The number of points per input dimension to sample at.
u_mod	The proportional values by which to inflate/deflate the relevant statistic.
intervals	The interval values of the implausibility cutoff at which to evaluate.
modified	The statistic to modify: obs, disc, var or hp (see above)
maxpoints	The maximum number of points to evaluate at

Details

The reduction in space is found by evaluating a p^d regular grid, where p is chosen by ppd and d is the dimension of the input space. Larger values of p will give a more accurate reflection of the space removed, at a corresponding computational cost. For the purpose of quick-and-dirty diagnostics, ppd = 5 is sufficient: the default is 10.

The parameter modified can be one of three strings: 'obs' corresponding to observation uncertainty; 'disc' corresponding to internal and external discrepancy (as given in Emulator$disc); 'var' corresponding to global emulator variance (as given by Emulator$u_sigma), and 'hp' corresponding to the hyperparameters of the emulator correlation structure. In the first case, the implausibilities are recalculated for each inflation value; in the other two cases the emulators are retrained. For this reason, the 'var' and 'hp' options are computationally more intensive. The default is 'obs'.

The inflationary/deflationary values are chosen by u_mod: the default is to take 80%, 90%, 100%, 110%, and 120% of the original value as the variation. The proportion of points deemed non-implausible is checked at a set of implausibility cutoffs defined by intervals, and a plot is returned showing the relevant data.

Value

A ggplot object

See Also

space_removal for a numeric representation of space removed.

Other visualisation tools: behaviour_plot(), diagnostic_wrap(), effect_strength(), emulator_plot(), hit_by_wave(), output_plot(), plot_actives(), plot_lattice(), plot_wrap(), simulator_plot(), validation_pairs(), wave_dependencies(), wave_points(), wave_values()

Examples

 space_removed(SIREmulators$ems, SIREmulators$targets, ppd = 5)
 space_removed(SIREmulators$ems$nS, SIREmulators$targets,
  ppd = 5, u_mod = seq(0.75, 1.25, by = 0.25), intervals = seq(2, 6, by = 0.1))

hmer documentation built on June 22, 2024, 9:22 a.m.