Jeffreys interval polish

Cargo.toml

@@ -89,8 +89,11 @@ pest_derive = "2"
 regex = "1"
 
 # --- Numerical computing ---
+libm = "0.2"
 nalgebra = "0.35"
 num = "0.4"
+# Dev-only differential oracle for special-function tests (see design/jeffreys-pecos-num.md)
+puruspe = "0.4"
 num-complex = "0.4"
 num-traits = "0.2"
 num-bigint = { version = "0.4", features = ["serde"] }

crates/pecos-num/Cargo.toml

@@ -38,5 +38,12 @@ rustworkx-core.workspace = true
 serde = { workspace = true, features = ["derive"] }
 serde_json.workspace = true
 
+# Deterministic libm (musl-derived) for special functions; see design/jeffreys-pecos-num.md
+libm.workspace = true
+
+[dev-dependencies]
+# Differential oracle for special-function tests only -- never a runtime dependency
+puruspe.workspace = true
+
 [lints]
 workspace = true

crates/pecos-num/src/lib.rs

@@ -58,4 +58,6 @@ pub use linalg::{matrix_exp, matrix_log};
 pub use optimize::{BrentqOptions, NewtonOptions, OptimizeError, brentq, newton};
 pub use polynomial::{Poly1d, PolynomialError, polyfit};
 pub use special::{betainc_inv, betainc_reg, ln_gamma};
-pub use stats::{jeffreys_interval, mean};
+pub use stats::{
+    JeffreysError, JeffreysEstimator, JeffreysInterval, jeffreys_interval, jeffreys_point, mean,
+};

crates/pecos-num/src/prelude.rs

@@ -31,13 +31,11 @@ pub use crate::random;
 
 // Re-export statistical functions
 pub use crate::stats::{
-    jackknife_resamples, jackknife_stats, jackknife_stats_axis, jackknife_weighted,
-    jeffreys_interval, mean, mean_axis, std, std_axis, weighted_mean,
+    JeffreysError, JeffreysEstimator, JeffreysInterval, jackknife_resamples, jackknife_stats,
+    jackknife_stats_axis, jackknife_weighted, jeffreys_interval, jeffreys_point, mean, mean_axis,
+    std, std_axis, weighted_mean,
 };
 
-// Re-export special functions
-pub use crate::special::{betainc_inv, betainc_reg, ln_gamma};
-
 // Re-export mathematical traits (use these for polymorphism!)
 pub use crate::math::{
     Abs, Acos, Acosh, Asin, Asinh, Atan, Atan2, Atanh, Ceil, Cos, Cosh, Exp, Floor, Ln, LogBase,