Hawkynt

Ran2 (Numerical Recipes)

Combined linear congruential generator with Bays-Durham shuffle from Numerical Recipes. Uses two LCGs with moduli 2147483563 and 2147483399, combined with a 32-entry shuffle table. Long period (~2.3 × 10^18) makes it suitable for Monte Carlo simulations. Returns uniform deviates in range [0.0, 1.0).

Properties

Property	Value
Category	Random Number Generators
Sub-category	Linear Congruential Generator
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	William H. Press, Saul A. Teukolsky, William T. Vetterling, Brian P. Flannery
Year	1988
Origin	🇺🇸 United States
Source	algorithms/random/ran2.js

Parameters

Parameter	Supported values
Seed sizes	1 byte (8 bits) to 8 bytes (64 bits)

Capabilities

Flag	Value
IsDeterministic	Yes
IsCryptographicallySecure	No

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Documentation

• Numerical Recipes in C: The Art of Scientific Computing (2nd Edition)
• Ran2 Reference Implementation (GitHub)
• L’Ecuyer, P. (1988): Efficient and Portable Combined Random Number Generators

References

• Numerical Recipes Legacy Code
• Press et al.: Numerical Recipes - The Art of Scientific Computing
• GNU Scientific Library - Numerical Recipes generators

Test vectors

4 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — Seed=-1 (initializes to 1) - First 10 double values

Field	Value
seed	01
outputSize	80
input	null
expected	b6f1203fae43d23f7f8944440537d03f 1fc0e3bb8dedb73f1c39ae78ce78e33f 319bf29ad1e8ec3f5f33a66e5f12c93f 3eeface507a1dd3faa46f475760cee3f ff36d0199b48c03f9554ad7d9d9eda3f

Vector 2 — Seed=-12345 - First 10 double values

Field	Value
seed	3039
outputSize	80
input	null
expected	badb7eba23da9b3fe93f0bec0e2fae3f f64a547e0d9dce3fb1bf8e980eef983f ff588c73f56fbd3ffc6d260f1570e63f 457e15f89053e33fde9aae964961db3f 609a3f0f7f17e83fa0f7e414a531da3f

Vector 3 — Seed=-123456789 - First 10 double values

Field	Value
seed	075bcd15
outputSize	80
input	null
expected	8f9ee4ec1528d13f4990dfaf42eaea3f 19cb792883d2db3f14885e8e6fa3d53f b8027ff3df5bad3fb6823a24134fe73f bb22f6ceb581c03f5f44f0f46600d83f 552134d1d19fe13f06c43e5d542ed03f

Vector 4 — Seed=-1 - First value only (initialization test)

Field	Value
seed	01
outputSize	8
input	null
expected	b6f1203fae43d23f

---

← All algorithms

This site is open source. Improve this page.