Drand48 Drand48_sub Erand48 Jrand48 Lcong48 Lrand48 Lrand48_sub Mrand48 Mrand48_sub Nrand48 Seed48 Srand48

Lcong48() Sub Lcong48 ( P() As  Integer ) Sets up parameters for random number generators, and initializes seed for Drand48, Lrand48 and Mrand48 (Linear congruential method) Purpose This routine sets up parameters for Rand48 series random number generators, and initializes seed for Drand48, Lrand48 and Mrand48. Parameters [in] P() Array P(6) For linear congruential method Xn+1 = (a*Xn + c) mod m, sets up the multiplicand a and the addend c (m (= 2^48) cannot be altered). Also, seed value for Drand48, Lrand48 and Mrand48 is initialized.   P(0)〜P(2): Seed value   P(3)〜P(5): multiplicand a. (default = 25214903917)   P(6): addend c. (default = 11) Note The multiplicand a and the addend c, set up by Lcong48(), will be reset to the default values by calling Seed48 or Srand48. Example Program Generate 10 real pseudo random numbers in [0, 1). Different random number series is generated from default setting by changing parameters with Lcong48(). Seed48() resets parameters to default setting as well as seed value. The parameters used by Erand48() are also reset by Seed48(). Sub Ex_Lcong48() Dim P(6) As Integer, XSeed(2) As Integer, Seed As Long, I As Long Seed = 13 Call Srand48(Seed) XSeed(0) = &H330E: XSeed(1) = Seed Mod (2 ^ 16): XSeed(2) = Seed / (2 ^ 16) P(0) = XSeed(0): P(1) = XSeed(1): P(2) = XSeed(2) P(3) = &HE66D: P(4) = &HDEEC: P(5) = &H15: P(6) = 11 '-- default P(5) = &H5 Call Lcong48(P()) Debug.Print "Parameters changed" For I = 1 To 10 Debug.Print Drand48(), Erand48(XSeed()) Next XSeed(0) = &H330E: XSeed(1) = Seed Mod (2 ^ 16): XSeed(2) = Seed / (2 ^ 16) Call Srand48(Seed) Debug.Print "Parameters reset" For I = 1 To 10 Debug.Print Drand48(), Erand48(XSeed()) Next End Sub Example Results Parameters changed 0.68217601750894 0.68217601750894 3.23807500276132E-02 3.23807500276132E-02 0.923458890562085 0.923458890562085 0.455927073812695 0.455927073812695 0.53016547731848 0.53016547731848 0.513544770641587 0.513544770641587 0.8044530201208 0.8044530201208 0.48267436264458 0.48267436264458 0.100180215892042 0.100180215892042 0.502789161459759 0.502789161459759 Parameters reset 0.49125804875894 0.49125804875894 0.909578015652613 0.909578015652613 0.696163968687085 0.696163968687085 0.922235667562695 0.922235667562695 0.42372016481848 0.42372016481848 0.593378755016587 0.593378755016587 0.1323338794958 0.1323338794958 0.45044780014458 0.45044780014458 0.269613809642042 0.269613809642042 0.820416114584759 0.820416114584759