Reuses the stored transition-matrix blocks to compute a compact set of numerical and physics-based diagnostics for one or more stored frequencies. The summary combines:
monostatic reconstruction residuals,
reciprocity residuals under incident/receive-angle exchange,
an optical-theorem residual based on forward scattering and the integrated differential cross section,
block-level conditioning indicators from the stored transition-matrix blocks,
and, for prolate/oblate targets, an equal-volume sphere-to-spheroid continuation path that checks whether the monostatic response deforms smoothly away from the exact sphere limit.
These checks are meant to help distinguish "the post-processing is self-consistent" from "the retained solve was also numerically comfortable," which is especially helpful for the newer nonspherical TMM branches. For stored cylinders, the current diagnostics are intentionally limited to exact monostatic reconstruction because a validated retained cylinder angular operator is not yet available.
Usage
tmm_diagnostics(
object,
frequency = NULL,
theta_body = NULL,
phi_body = NULL,
reciprocity_pairs = NULL,
n_theta = 61,
n_phi = 121,
continuation_steps = 6L
)Arguments
- object
Scatterer-object previously evaluated with
target_strength(..., model = "TMM", store_t_matrix = TRUE).- frequency
Optional stored frequency or vector of stored frequencies (Hz). Defaults to all stored frequencies.
- theta_body
Incident polar angle (radians) used for the monostatic and optical-theorem checks. Defaults to the stored TMM incident angle.
- phi_body
Incident azimuth angle (radians) used for the monostatic and optical-theorem checks. Defaults to the stored TMM incident angle.
- reciprocity_pairs
Optional data frame giving explicit reciprocity test angles. Must contain
theta_body,phi_body,theta_scatter, andphi_scattercolumns in radians.- n_theta
Number of polar-angle grid points used by the optical-theorem integration check.
- n_phi
Number of azimuth-angle grid points used by the optical-theorem integration check.
- continuation_steps
Number of equal-volume aspect-ratio steps used for the sphere-to-spheroid continuation check on prolate and oblate targets. Set to
0or1to skip the continuation path. Ignored for non-spheroidal targets.
Value
A list with components:
summaryPer-frequency diagnostic summary.
block_metricsPer-frequency block-level conditioning and transpose-residual summaries.
continuationEqual-volume sphere-to-spheroid continuation path for spheroidal targets, or
NULLfor other shapes.
Examples
target <- fls_generate(
shape = sphere(radius_body = 0.005, n_segments = 20),
g_body = 1,
h_body = 1
)
stored <- target_strength(
target,
frequency = 12e3,
model = "tmm",
boundary = "pressure_release",
store_t_matrix = TRUE
)
tmm_diagnostics(stored, n_theta = 5, n_phi = 9)
#> $summary
#> shape coordinate_system boundary frequency monostatic_abs_residual
#> 1 Sphere spherical pressure_release 12000 8.673617e-19
#> monostatic_rel_residual reciprocity_rel_residual sigma_total sigma_ext
#> 1 1.867274e-16 4.251432e-17 0.0002918541 0.0003078102
#> optical_theorem_sign optical_theorem_rel_residual min_block_rcond
#> 1 1 0.0518376 1.128043e-06
#> max_block_cond_est max_block_transpose_residual
#> 1 886491.1 2.066084e-17
#> continuation_target_aspect_ratio continuation_max_abs_step_TS
#> 1 NA NA
#> continuation_max_abs_second_diff_TS continuation_any_nonfinite
#> 1 NA NA
#>
#> $block_metrics
#> $block_metrics$`12000`
#> m n_terms rcond transpose_residual
#> 1 0 6 1.255165e-05 2.066084e-17
#> 2 1 5 1.128043e-06 3.690615e-18
#> 3 2 4 3.340586e-06 4.772712e-18
#> 4 3 3 5.818129e-05 4.471309e-18
#> 5 4 2 3.854585e-03 2.200130e-18
#> 6 5 1 1.000000e+00 0.000000e+00
#>
#>
#> $continuation
#> NULL
#>