void setall(long iseed1,long iseed2)
/*
**********************************************************************
void setall(long iseed1,long iseed2)
SET ALL random number generators
Sets the initial seed of generator 1 to ISEED1 and ISEED2. The
initial seeds of the other generators are set accordingly, and
all generators states are set to these seeds.
This is a transcription from Pascal to Fortran of routine
Set_Initial_Seed from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
iseed1 -> First of two integer seeds
iseed2 -> Second of two integer seeds
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gssst(long getset,long *qset);
extern void gscgn(long getset,long *g);
extern long Xm1,Xm2,Xa1vw,Xa2vw,Xig1[],Xig2[];
long T1;
long g,ocgn;
long qrgnin;
T1 = 1;
/*
TELL IGNLGI, THE ACTUAL NUMBER GENERATOR, THAT THIS ROUTINE
HAS BEEN CALLED.
*/
gssst(1,&T1);
gscgn(0L,&ocgn);
/*
Initialize Common Block if Necessary
*/
gsrgs(0L,&qrgnin);
if(!qrgnin) inrgcm();
*Xig1 = iseed1;
*Xig2 = iseed2;
initgn(-1L);
for(g=2; g<=numg; g++) {
*(Xig1+g-1) = mltmod(Xa1vw,*(Xig1+g-2),Xm1);
*(Xig2+g-1) = mltmod(Xa2vw,*(Xig2+g-2),Xm2);
gscgn(1L,&g);
initgn(-1L);
}
gscgn(1L,&ocgn);
#undef numg
}
void initgn(long isdtyp)
/*
**********************************************************************
void initgn(long isdtyp)
INIT-ialize current G-e-N-erator
Reinitializes the state of the current generator
This is a transcription from Pascal to Fortran of routine
Init_Generator from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
isdtyp -> The state to which the generator is to be set
isdtyp = -1 => sets the seeds to their initial value
isdtyp = 0 => sets the seeds to the first value of
the current block
isdtyp = 1 => sets the seeds to the first value of
the next block
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gscgn(long getset,long *g);
extern long Xm1,Xm2,Xa1w,Xa2w,Xig1[],Xig2[],Xlg1[],Xlg2[],Xcg1[],Xcg2[];
long g;
long qrgnin;
/*
Abort unless random number generator initialized
*/
gsrgs(0L,&qrgnin);
if(qrgnin) goto S10;
fprintf(stderr,"%s\n",
" INITGN called before random number generator initialized -- abort!");
exit(1);
S10:
gscgn(0L,&g);
if(-1 != isdtyp) goto S20;
*(Xlg1+g-1) = *(Xig1+g-1);
*(Xlg2+g-1) = *(Xig2+g-1);
goto S50;
S20:
if(0 != isdtyp) goto S30;
goto S50;
S30:
/*
do nothing
*/
if(1 != isdtyp) goto S40;
*(Xlg1+g-1) = mltmod(Xa1w,*(Xlg1+g-1),Xm1);
*(Xlg2+g-1) = mltmod(Xa2w,*(Xlg2+g-1),Xm2);
goto S50;
S40:
fprintf(stderr,"%s\n","isdtyp not in range in INITGN");
exit(1);
S50:
*(Xcg1+g-1) = *(Xlg1+g-1);
*(Xcg2+g-1) = *(Xlg2+g-1);
#undef numg
}
long ignlgi(void)
/*
**********************************************************************
long ignlgi(void)
GeNerate LarGe Integer
Returns a random integer following a uniform distribution over
(1, 2147483562) using the current generator.
This is a transcription from Pascal to Fortran of routine
Random from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gssst(long getset,long *qset);
extern void gscgn(long getset,long *g);
extern void inrgcm(void);
extern long Xm1,Xm2,Xa1,Xa2,Xcg1[],Xcg2[];
extern long Xqanti[];
long ignlgi,curntg,k,s1,s2,z;
long qqssd,qrgnin;
/*
IF THE RANDOM NUMBER PACKAGE HAS NOT BEEN INITIALIZED YET, DO SO.
IT CAN BE INITIALIZED IN ONE OF TWO WAYS : 1) THE FIRST CALL TO
THIS ROUTINE 2) A CALL TO SETALL.
*/
gsrgs(0L,&qrgnin);
if(!qrgnin) inrgcm();
gssst(0,&qqssd);
if(!qqssd) setall(1234567890L,123456789L);
/*
Get Current Generator
*/
gscgn(0L,&curntg);
s1 = *(Xcg1+curntg-1);
s2 = *(Xcg2+curntg-1);
k = s1/53668L;
s1 = Xa1*(s1-k*53668L)-k*12211;
if(s1 < 0) s1 += Xm1;
k = s2/52774L;
s2 = Xa2*(s2-k*52774L)-k*3791;
if(s2 < 0) s2 += Xm2;
*(Xcg1+curntg-1) = s1;
*(Xcg2+curntg-1) = s2;
z = s1-s2;
if(z < 1) z += (Xm1-1);
if(*(Xqanti+curntg-1)) z = Xm1-z;
ignlgi = z;
return ignlgi;
#undef numg
}
void advnst(long k)
/*
**********************************************************************
void advnst(long k)
ADV-a-N-ce ST-ate
Advances the state of the current generator by 2^K values and
resets the initial seed to that value.
This is a transcription from Pascal to Fortran of routine
Advance_State from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
k -> The generator is advanced by2^K values
**********************************************************************
** Buttrey note: replaced all exit() calls with return()s -- Jan 2015.
** Also replaced all fprintf's with Rprintf
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gscgn(long getset,long *g);
extern long Xm1,Xm2,Xa1,Xa2,Xcg1[],Xcg2[];
static long g,i,ib1,ib2;
static long qrgnin;
/*
Abort unless random number generator initialized
*/
gsrgs(0L,&qrgnin);
if(qrgnin) goto S10;
Rprintf(" ADVNST called before random generator initialized - ABORT");
return;
S10:
gscgn(0L,&g);
ib1 = Xa1;
ib2 = Xa2;
for(i=1; i<=k; i++) {
ib1 = mltmod(ib1,ib1,Xm1);
ib2 = mltmod(ib2,ib2,Xm2);
}
setsd(mltmod(ib1,*(Xcg1+g-1),Xm1),mltmod(ib2,*(Xcg2+g-1),Xm2));
/*
NOW, IB1 = A1**K AND IB2 = A2**K
*/
#undef numg
}
void setant(long qvalue)
/*
**********************************************************************
void setant(long qvalue)
SET ANTithetic
Sets whether the current generator produces antithetic values. If
X is the value normally returned from a uniform [0,1] random
number generator then 1 - X is the antithetic value. If X is the
value normally returned from a uniform [0,N] random number
generator then N - 1 - X is the antithetic value.
All generators are initialized to NOT generate antithetic values.
This is a transcription from Pascal to Fortran of routine
Set_Antithetic from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
qvalue -> nonzero if generator G is to generating antithetic
values, otherwise zero
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gscgn(long getset,long *g);
extern long Xqanti[];
long g;
long qrgnin;
/*
Abort unless random number generator initialized
*/
gsrgs(0L,&qrgnin);
if(qrgnin) goto S10;
fprintf(stderr,"%s\n",
" SETANT called before random number generator initialized -- abort!");
exit(1);
S10:
gscgn(0L,&g);
Xqanti[g-1] = qvalue;
#undef numg
}
void setsd(long iseed1,long iseed2)
/*
**********************************************************************
void setsd(long iseed1,long iseed2)
SET S-ee-D of current generator
Resets the initial seed of the current generator to ISEED1 and
ISEED2. The seeds of the other generators remain unchanged.
This is a transcription from Pascal to Fortran of routine
Set_Seed from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
iseed1 -> First integer seed
iseed2 -> Second integer seed
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gscgn(long getset,long *g);
extern long Xig1[],Xig2[];
long g;
long qrgnin;
/*
Abort unless random number generator initialized
*/
gsrgs(0L,&qrgnin);
if(qrgnin) goto S10;
fprintf(stderr,"%s\n",
" SETSD called before random number generator initialized -- abort!");
exit(1);
S10:
gscgn(0L,&g);
*(Xig1+g-1) = iseed1;
*(Xig2+g-1) = iseed2;
initgn(-1L);
#undef numg
}
void getsd(long *iseed1,long *iseed2)
/*
**********************************************************************
void getsd(long *iseed1,long *iseed2)
GET SeeD
Returns the value of two integer seeds of the current generator
This is a transcription from Pascal to Fortran of routine
Get_State from the paper
L'Ecuyer, P. and Cote, S. "Implementing a Random Number Package
with Splitting Facilities." ACM Transactions on Mathematical
Software, 17:98-111 (1991)
Arguments
iseed1 <- First integer seed of generator G
iseed2 <- Second integer seed of generator G
**********************************************************************
*/
{
#define numg 32L
extern void gsrgs(long getset,long *qvalue);
extern void gscgn(long getset,long *g);
extern long Xcg1[],Xcg2[];
long g;
long qrgnin;
/*
Abort unless random number generator initialized
*/
gsrgs(0L,&qrgnin);
if(qrgnin) goto S10;
fprintf(stderr,"%s\n",
" GETSD called before random number generator initialized -- abort!");
exit(0);
S10:
gscgn(0L,&g);
*iseed1 = *(Xcg1+g-1);
*iseed2 = *(Xcg2+g-1);
#undef numg
}
void apprcirc(long *n, double *Hurst, double *L, int *cum, long *seed1,
long *seed2, double *output) {
/* function that generates a fractional Brownian motion or fractional */
/* Gaussian noise sample using the approximate circulant method. */
/* Input: *n determines the sample size N by N=2^(*n) */
/* *Hurst the Hurst parameter of the trace */
/* *L the sample is generated on [0,L] */
/* *cum = 0: fractional Gaussian noise is produced */
/* = 1: fractional Brownian motion is produced */
/* *seed1 seed1 for the random generator */
/* *seed2 seed2 for the random generator */
/* Output: *seed1 new seed1 of the random generator */
/* *seed2 new seed2 of the random generator */
/* *output the resulting sample is stored in this array */
long i, N, halfN, generator;
double scaling, H;
double *pow_spec;
double aux;
complex *a;
halfN = pow(2,*n);
H = *Hurst;
N = 2*halfN;
/* set random generator and seeds */
snorm();
generator = 1;
gscgn(1, &generator);
setall(*seed1,*seed2);
/* allocate memory */
pow_spec = (double*) malloc((halfN+1)*sizeof(double));
/* approximate spectral density */
FGN_spectrum(pow_spec,halfN,H);
a = malloc(N*sizeof(complex));
a[0].re = sqrt(2*(pow(N,2*H)-pow(N-1,2*H)))*snorm();
a[0].im = 0.;
a[halfN].re = sqrt(2*pow_spec[halfN])*snorm();
a[halfN].im = 0.;
for(i=1; i<halfN; i++) {
aux = sqrt(pow_spec[i]);
a[i].re = aux*snorm();
a[i].im = aux*snorm();
}
for(i=halfN+1; i<N; i++) {
a[i].re = a[N-i].re;
a[i].im = -a[N-i].im;
}
/* real part of Fourier transform of a_re + i a_im gives sample path */
fft(N,a,1,1.0);
/* rescale to obtain a sample of size 2^(*n) on [0,L] */
scaling = pow(*L/halfN,H)/sqrt(2*N);
for(i=0;i<halfN;i++) {
output[i] = scaling*(a[i].re);
if (*cum && i>0) {
output[i] += output[i-1];
}
}
/* store the new random seeds and free memory */
getsd(seed1,seed2);
free(pow_spec);
free(a);
}
