func splineCosmo(om, zmin, zmax float64) (*spline.Spline, error) {
lcdm := cosmo.NewFlatLCDMSimple(om, 1)
nz := 1000
dz := (zmax - zmin) / float64(nz)
avals := make([]float64, nz+1)
zvals := make([]float64, nz+1)
for i := 0; i <= nz; i++ {
zvals[i] = zmin + float64(i)*dz
avals[i] = cosmo.Z2A(zvals[i])
}
dist := cosmo.ComDis(lcdm, avals)
sp, err := spline.New(spline.Cubic, zvals, dist)
if err != nil {
return nil, err
}
return sp, nil
}
// The weight file is assumed to have a first header line, and then two columns
// with z and n(z)
func readWeight(wfn string, Pk float64) (*spline.Spline, error) {
var err error
fmt.Println("Reading in ", wfn)
var wstr fkpstruct
wstr.Pk = Pk
if err := lineio.Read(wfn, &wstr); err != nil {
return nil, err
}
sp, err := spline.New(spline.Cubic, wstr.zz, wstr.fkp)
if err != nil {
return nil, err
}
// Test the spline
plot, err := gnuplot.New(false)
defer close(plot)
if err != nil {
return nil, err
}
plot <- "set term pngcairo"
plot <- "set output 'fkp_test.png'"
plot <- "plot '-' w points ps 3, '-' w lines lw 2"
for i := range wstr.zz {
plot <- fmt.Sprintln(wstr.zz[i], wstr.fkp[i])
}
plot <- "e"
var nz float64
for z1 := wstr.zz[0]; z1 < wstr.zz[len(wstr.zz)-1]; z1 = z1 + 0.001 {
if nz, err = sp.Eval(z1); err != nil {
return nil, err
}
plot <- fmt.Sprint(z1, nz)
}
plot <- "e"
plot <- "set output"
// Return the spline
return sp, nil
}