Returns pseudo-random numbers in the range 0 to 1

This is a
simple random number generator providing deviates in the range 0 to 1, with period of
2$\ast $$\ast $26,
and to 6 or 7 digits accuracy. It is based upon Ahrens, Dieter & Grube

`’`

s TOMS599 routines. Note
that there is no STATUS argument for efficiency. RESULT = PDA_RAND( X
)

This is a dummy variable required by the Fortran
standard.

The pseudo-random deviate.

The initial seed MUST be set using routine PDA_RNSED (equivalent to NAG

`’`

s
G05CBF). If it has not, there is no guarantee that sensible values will be returned from
this function. Ahrens, J.H., Dieter, U. & Grube, A., 1970,

`"`

Pseudo-random
numbers: a new proposal for the choice of multiplicators`"`

, Computing, 6, pp.121–138.