Fisher Information

Information gradient, statistical curvature, parameter sensitivity
distributionaldim statistical manifold5 metrics

What It Measures

How sharply the signal's distribution changes when you perturb the histogram.

Treats the 16-bin histogram as a point on a statistical manifold — a curved space where each point represents a probability distribution. The Fisher information matrix measures the curvature at that point: high curvature means a small change in the data would radically shift the distribution (informationally sensitive). Low curvature means the distribution is robust to perturbation.

Metrics

effective_dimension

How many independent directions matter in the Fisher matrix? Computed as the participation ratio of eigenvalues. De Bruijn, phyllotaxis, and circle map quasiperiodic all score 16.0 (the maximum — all 16 bins are equally important, so the statistical manifold is fully 16-dimensional). Seismic b-value scores 2.27 (its distribution has only 2-3 effective degrees of freedom, despite occupying many bins). This measures the intrinsic dimensionality of the signal's distributional footprint.

log_det_fisher

Logarithm of the determinant of the Fisher matrix. This is the log-volume element of the statistical manifold at the data's location. Collatz parity (137.4), Symbolic Henon (137.4), and Fibonacci word (137.3) score highest — their sparse, peaked distributions create enormous Fisher curvature (tiny probabilities in many bins produce large 1/p terms). De Bruijn scores 44.4 (the minimum for a 16-bin uniform — all probabilities equal 1/16). The 93-unit range across the atlas spans 40 orders of magnitude in actual determinant value.

trace_fisher

Sum of diagonal Fisher matrix entries (sum of 1/p_i for each bin). Collatz parity (229,605), Symbolic Henon (229,604), and Fibonacci word (229,604) score highest for the same reason as log_det: near-empty bins dominate the trace. De Bruijn scores 256 (16 bins, each with probability 1/16, so 16 * 16 = 256). Trace and log_det are correlated but not identical: log_det captures the product of per-bin information (sensitive to the emptiest bin), while trace captures the sum (sensitive to the total information budget).

geodesic_velocity

Mean Fisher-Rao geodesic distance between windowed histograms of consecutive segments. Random Steps (1.86) scores highest — each segment has a genuinely different distribution. Exponential Chirp (1.57) and financial returns also score high. Constants and periodic orbits score 0.0 (identical windows). This measures how fast the signal moves through the statistical manifold — the "speed" of distributional change. Evolved via ShinkaEvolve.

velocity_spectral_gini

Gini coefficient of the power spectrum of the geodesic velocity time series. BTC Close (1.0) and Fibonacci QC (1.0) score highest — their distributional dynamics have energy concentrated at a few frequencies. Logistic period-2 (0.0) scores zero. High spectral Gini means the distributional change is periodic or bursty (energy at specific frequencies); low means it's broadband. Evolved via ShinkaEvolve.

Atlas Rankings

effective_dimension
SourceDomainValue
De Bruijn Sequencenumber_theory16.0000
Gray Code Counterexotic16.0000
Phyllotaxisbio15.9959
···
Seismic b-value (SoCal)geophysics2.2681
Ocean Wind (Buoy)climate2.4615
Sandpileexotic2.4795
geodesic_velocity
SourceDomainValue
Random Stepsexotic1.8645
PID Controllerexotic1.6711
Accel Sitmotion1.5191
···
Constant 0xFFnoise0.0000
Logistic r=3.5 (Period-4)chaos0.0000
Logistic r=3.2 (Period-2)chaos0.0000
log_det_fisher
SourceDomainValue
Constant 0x00noise145.5765
Collatz Paritynumber_theory137.3795
Symbolic Henonexotic137.3695
···
De Bruijn Sequencenumber_theory44.3614
Gray Code Counterexotic44.3614
Phyllotaxisbio44.3633
trace_fisher
SourceDomainValue
Constant 0x00noise246001.0009
Collatz Paritynumber_theory229604.5187
Symbolic Henonexotic229604.4734
···
De Bruijn Sequencenumber_theory256.0000
Gray Code Counterexotic256.0000
Phyllotaxisbio256.0621
velocity_spectral_gini
SourceDomainValue
Rössler Hyperchaoschaos0.8336
Sawtooth Wavewaveform0.8071
Van der Pol Oscillatorexotic0.7890
···
Constant 0xFFnoise0.0000
Logistic r=3.5 (Period-4)chaos0.0000
Logistic r=3.74 (Period-5 Window)chaos0.0000

When It Lights Up

Fisher Information geometry detects a specific distributional property: how many bins are nearly empty. Signals that use only a few of 16 bins — binary sequences, periodic orbits, sparse event streams — create Fisher matrices with explosive curvature because the nearly-empty bins contribute 1/p terms near infinity (Laplace smoothing prevents actual infinity but preserves the relative ranking). In the atlas, effective_dimension separates "genuinely multi-valued" signals (dimension near 16) from "effectively binary" signals (dimension 2-4), providing a distributional complexity measure independent of entropy.

Open in Atlas
← Julia SetWasserstein →