Performance improvements

[jlogan-cfs]

2.6.0 2025-10-15

Substantial performance improvement for flux_density_linear_filament Biot-Savart methods.
This also improves performance in calculations that use these methods, such as linear filament
body force density calcs.

Added

• Rust
  • Add dot3f and cross3f 32-bit float variants

Changed

• Rust
  • Use mixed-precision method for flux_density_linear_filament_scalar
  • High-dynamic-range part of the calc is still done using 64-bit floats
  • Low-dynamic-range part of the calc is now done using 32-bit floats
    • All addition operations in 32-bit section are done using
      fused multiply-add operations, usually chained to defer
      roundoff to final operation. As a result, total roundoff error
      accumulated in this section is minimal.
  • Return is upcast back to 64-bit float to support precise summation downstream
  • 1.4-2x speedup without any meaningful loss of precision
    • No change to unit test tolerances needed; unlike an all-32-bit implementation,
      this mixed-precision method passes all the same tests as the 64-bit-only method
• Python
  • Update dep versions
  • Use latest rust backend version, which includes 1.4-2x speedup for flux_density_linear_filament Biot-Savart calcs

[mdavids-cfs]

Looks good