Re: Fortran, no RAN ?

On 6/17/2024 6:12 PM, Arne Vajhøj wrote:

On 6/17/2024 12:09 AM, Michael Brown wrote:

But the question now is why RAN(I1, I2) works on the VAX compiler,and not on the X86_64 compiler. And what is it doing with those 2 parameters on the VAX so I can simulate it somehow.

 Are you sure that it is intrinsic and not something picked
up from some library?
 What type is RNDOM? Default REAL*4? Or Integer*4?
 If INTEGER*4 then my guess would be that:
 RAN(I1, I2)
 is:
 RAN_INT_IN_INTERVAL(LOW_BOUND, HIGH_BOUND)

But if RNDOM is REAL*4 then my guess would be:
RAN_LONGER_CYCLE(SEED1, SEED2)
Example:
       real*4 function ran2arg(seed1, seed2)
       implicit none
       integer*4 seed1, seed2
       integer*4 temp
       real*4 dummy
       temp = xor(seed1, seed2)
       ran2arg = ran(temp)
       seed1 = xor(ishc(seed1, 1), temp)
       seed2 = xor(ishc(seed2, -1), temp)
       end
Disclaimer: I do not know if the cycle from this one is actual longer.
Arne