void RngStream_AdvanceState (RngStream g, long e, long c)
{
double B1[3][3], C1[3][3], B2[3][3], C2[3][3];
if (e > 0) {
MatTwoPowModM (A1p0, B1, m1, e);
MatTwoPowModM (A2p0, B2, m2, e);
} else if (e < 0) {
MatTwoPowModM (InvA1, B1, m1, -e);
MatTwoPowModM (InvA2, B2, m2, -e);
}
if (c >= 0) {
MatPowModM (A1p0, C1, m1, c);
MatPowModM (A2p0, C2, m2, c);
} else {
MatPowModM (InvA1, C1, m1, -c);
MatPowModM (InvA2, C2, m2, -c);
}
if (e) {
MatMatModM (B1, C1, C1, m1);
MatMatModM (B2, C2, C2, m2);
}
MatVecModM (C1, g->Cg, g->Cg, m1);
MatVecModM (C2, &g->Cg[3], &g->Cg[3], m2);
}
static void MatPowModM (double A[3][3], double B[3][3], double m, long c)
/* Compute matrix D = A^c Mod m ; works even if A = B */
{
int i, j, n = c;
double W[3][3];
/* initialize: W = A; B = I */
for (i = 0; i <= 2; i++) {
for (j = 0; j <= 2; ++j) {
W[i][j] = A[i][j];
B[i][j] = 0.0;
}
}
for (j = 0; j <= 2; ++j) B[j][j] = 1.0;
/* Compute B = A^c mod m using the binary decomposition of c */
while (n > 0) {
if (n % 2) MatMatModM (W, B, B, m);
MatMatModM (W, W, W, m);
n /= 2;
}
}
static void MatTwoPowModM (double A[3][3], double B[3][3], double m, long e)
/* Compute matrix B = (A^(2^e) Mod m); works even if A = B */
{
int i, j;
/* initialize: B = A */
if (A != B) {
for (i = 0; i <= 2; i++) {
for (j = 0; j <= 2; ++j) B[i][j] = A[i][j];
}
}
/* Compute B = A^{2^e} */
for (i = 0; i < e; i++) MatMatModM (B, B, B, m);
}