ran - return a random number between 0 and 1
real function ran (i) integer*4 i
Repeated calls to ran generate random numbers with a uniform distribution.
See lcrans(3M).
The range includes 0.0 and excludes 1.0. The algorithm is a multiplicative, congruential type, general random number generator. In general, the value of i is set once during execution of the calling program. The initial value of i should be a large odd integer. Each call to ran returns the next random number in the sequence.
To get a different sequence of random numbers each time you run the calling program, you must set the argument i to a different initial value for each run.
Usage:
real r, ran integer*4 i i = ... ... r = ran(i)
Example:
demo% cat ran1.f * ran1.f <-- Generate random numbers integer*4 i, n real r(10) i = 760013 do n = 1, 10 r(n) = ran ( i ) end do write ( *, "( 5 f11.6 )" ) r end demo% f77 -silent ran1.f demo% a.out 0.222058 0.299851 0.390777 0.607055 0.653188 0.060174 0.149466 0.444353 0.002982 0.976519 demo%
libfsu.a
lcrans, addrans, and shufrans in the Numerical Computation Guide