Blend Crossover (BLX-α).

For each gene position, offspring are sampled uniformly from [min - α·d, max + α·d] where d = |p1 - p2| is the parent distance. Clamped to per-gene bounds. α defaults to 0.5.

See Eshelman & Schaffer 1993.

Simulated Binary Crossover (SBX).

Mimics the offspring distribution of single-point crossover for real-valued genes. The spread factor η controls how far offspring can stray from parents (higher η = closer to parents). Default η = 2.

See Deb & Agrawal 1995.