CosmoCoffee

I was running a quick consistency check between power spectra generated in pyCAMB and the command line executable and I'm a bit confused about some of the output. I've created an interpolation object:
where 'pars' has the same cosmology as the params.ini used in the executable. The ratio of the two is plot here, which gives exactly what you'd expect:



I then tried to do the same with the CDM power spectrum, by setting changing in the params.ini file, and setting
in the python program. When I compare these two power spectra however, I get:



so the power spectra are no longer the same. Am I right in expecting them to be the same, or am I attempting to get the CDM power spectrum the wrong way? Do var1 and var2 not select which fluids we want power spectra for?

Your second python example should raise an error because delta_CDM is not recognised (should be all lower case).

You need to set var2 as well as var1 for an autospectrum of delta_cdm: var1='delta_cdm,var2 ='delta_cdm'.

You can also use

camb.model.transfer_power_var.value=2

to change the default variable globally.

Thanks, that's fixed it! (and yes you're right, delta_CDM did return an error, I had only var1="delta_cdm" to generate the second plot).