real function h1(x)
! sigma=1.0/sqrt(2.0)
sigma=1.0
xlim=sigma/sqrt(6.0)
ax=abs(x)
sgnx=1.0
if(x.lt.0) sgnx=-1.0
if(ax.le.xlim) then
h1=x
else
z=exp(1.0/6.0 - (ax/sigma)**2)
h1=sgnx*sqrt(6.0)*sigma*(2.0/3.0 - 0.5*z)
endif
return
end function h1