**ACTION:**- Generate pseudo-random normal deviate or
*Gaussian residual*. **CALL:**`R = sla_GRESID (S)`

**GIVEN:**-

*S***R**standard deviation

**NOTES:**- 1.
- The results of many calls to this routine will be normally distributed with mean zero and standard deviation S.
- 2.
- The Box-Muller algorithm is used.
- 3.
- The implementation is machine-dependent.

**REFERENCE:**- Ahrens & Dieter, 1972.
*Comm.A.C.M.***15**, 873.

Starlink User Note 67

P. T. Wallace

12 October 1999

E-mail:ptw@star.rl.ac.uk