complex LoopToolsWrapper::PV_B00(const double mu2, const double p2,
const double m02, const double m12) const
{
setmudim(mu2);
std::complex<double> B00val = B00(p2, m02, m12);
return complex( B00val.real(), B00val.imag(), false );
}
TSIL_COMPLEX B0x (TSIL_REAL X, TSIL_COMPLEX S, TSIL_REAL QQ)
{
if (TSIL_FABS (X) < TSIL_TOL)
return B00(S,QQ);
if (TSIL_CABS (S) < TSIL_TOL)
return (1.0L - TSIL_LOG (X/QQ));
if (TSIL_CABS (1.0L - S/X) < 10.0L*TSIL_TOL)
return 2.0L - TSIL_LOG(X/QQ);
S = AddIeps(S);
return 2.0L + ((X - S)*TSIL_CLOG((X - S)/QQ) - X*TSIL_LOG(X/QQ))/S;
}
TSIL_COMPLEX B (TSIL_REAL X, TSIL_REAL Y, TSIL_COMPLEX S, TSIL_REAL QQ)
{
TSIL_REAL temp;
TSIL_COMPLEX sqDeltaSXY, lnbarX, lnbarY;
if (TSIL_FABS (X) < TSIL_FABS (Y)) {temp = Y; Y = X; X = temp;}
if (TSIL_FABS (X) < TSIL_TOL)
return B00(S,QQ);
if (TSIL_FABS (Y) < TSIL_TOL)
return B0x(X,S,QQ);
if (TSIL_CABS (S) < TSIL_TOL) {
if (TSIL_FABS (1.0L - Y/X) > 0.0L)
return (1.0L + (Y*TSIL_LOG(Y/QQ) - X*TSIL_LOG(X/QQ))/(X-Y));
else
return (-TSIL_LOG (X/QQ));
}
S = AddIeps(S);
sqDeltaSXY = TSIL_CSQRT(Delta(S, X, Y));
lnbarX = TSIL_LOG (X/QQ);
lnbarY = TSIL_LOG (Y/QQ);
/* Following avoids roundoff error for very negative s. */
if ((TSIL_CREAL(S) < -10.0L*(X+Y)) && (TSIL_CIMAG(S) < TSIL_TOL)) {
return (2.0L - 0.5L * (lnbarX + lnbarY) +
(sqDeltaSXY * TSIL_CLOG(0.5L*(X + Y - S + sqDeltaSXY)/Y) +
0.5L * (Y - X - sqDeltaSXY) * (lnbarX - lnbarY))/S);
}
return (2.0L - 0.5L * (lnbarX + lnbarY) +
(-sqDeltaSXY * TSIL_CLOG(0.5L*(X + Y - S - sqDeltaSXY)/X) +
0.5L * (Y - X - sqDeltaSXY) * (lnbarX - lnbarY))/S);
}
std::complex<double> H0(T p2, T m2a, T m2b, double scl2)
{
return 4.0*B00(p2, m2a, m2b, scl2) + G0(p2, m2a, m2b, scl2);
}
std::complex<double> B22(T p2, T m2a, T m2b, double scl2)
{
return B00(p2, m2a, m2b, scl2) - A0(m2a, scl2)/4.0 - A0(m2b, scl2)/4.0;
}
