/* This returns the linear power
* Delta = 4pi*k^3 P(k)/(2pi)^3
*/
double linear_power_spectrum(double xk)
{
static double *kk,*pknl,*y2,pnorm=-1,ahi,bhi;
static int flag=1,nk=1000,prev_cosmology=0;
double a,psp,x1[4],y1[4];
int i;
if(pnorm<0 || prev_cosmology!=RESET_COSMOLOGY)
{
pnorm=SIGMA_8/sigmac(8.0);
pnorm*=pnorm;
prev_cosmology=RESET_COSMOLOGY;
}
if(ITRANS>0)
psp=pow(xk,SPECTRAL_INDX)*pow(transfnc(xk),2.);
else
psp=pow(xk,SPECTRAL_INDX);
// printf("BOO %e %e\n",xk,psp*pnorm);
psp=psp*pnorm*xk*xk*xk/(2*PI*PI);
return(psp);
}
double func_sigmac(double xk)
{
double xkr,w,psp;
if(rad1>0)
{
xkr = xk*rad1;
w = 3*(sin(xkr)-xkr*cos(xkr))/(xkr*xkr*xkr);
w = w*w;
}
else
{
xkr = -rad1*xk;
w = exp(-xkr*xkr);
}
if(ITRANS>0)
psp=pow(xk,SPECTRAL_INDX)*pow(transfnc(xk),2.0);
else
psp=pow(xk,SPECTRAL_INDX);
psp=psp*w*xk*xk;
return(psp);
}