Ver 0.39.10

Author: Axect

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "peroxide"
-version = "0.39.9"
+version = "0.39.10"
 authors = ["axect <[email protected]>"]
 edition = "2018"
 description = "Rust comprehensive scientific computation library contains linear algebra, numerical analysis, statistics and machine learning tools with farmiliar syntax"

RELEASES.md

@@ -1,3 +1,8 @@
+# Release 0.39.10 (2025-07-11)
+
+- Fixed a bug in the adaptive step size control for all embedded Runge-Kutta methods.
+- Corrected the `BU` coefficient vector for the 7th order solution in the `RKF78` implementation.
+
 # Release 0.39.9 (2025-07-10)
 
 - Change implementation of Gauss-Legendre 4th order method

src/numerical/ode.rs

@@ -324,7 +324,7 @@ impl<BU: ButcherTableau> ODEIntegrator for BU {
                     error = error.max(dt * s.abs())
                 }
 
-                let factor = (self.tol() * dt / error).powf(0.2);
+                let factor = (self.tol() / error).powf(0.2);
                 let new_dt = self.safety_factor() * dt * factor;
                 let new_dt = new_dt.clamp(self.min_step_size(), self.max_step_size());
 
@@ -1102,7 +1102,7 @@ impl ButcherTableau for RKF78 {
     // BU_i = BE_i (8th order) - ErrorCoeff_i
     // ErrorCoeff_i = [-41/840, 0, ..., 0, -41/840 (for k11), 41/840 (for k12), 41/840 (for k13)]
     const BU: &'static [f64] = &[
-        41.0 / 420.0, // 41/840 - (-41/840)
+        0.0,
         0.0,
         0.0,
         0.0,
@@ -1112,9 +1112,9 @@ impl ButcherTableau for RKF78 {
         9.0 / 35.0,
         9.0 / 280.0,
         9.0 / 280.0,
-        41.0 / 420.0,  // 41/840 - (-41/840)
-        -41.0 / 840.0, // 0.0 - (41/840)
-        -41.0 / 840.0, // 0.0 - (41/840)
+        0.0,
+        41.0 / 840.0,
+        41.0 / 840.0,
     ];
 
     // Coefficients for the 8th order solution (used for error estimation)