camb: number of data points of matter power spectrum and its accuracy

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
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Pengyuan Gao
Posts: 9
Joined: September 06 2013
Affiliation: NAOC

camb: number of data points of matter power spectrum and it

Post by Pengyuan Gao » October 26 2014

Dear all,

I want to output matter power spectrum for latter interpolation.
How to change the number of data points of matter power spectrum to that I want ?
And How can I know the accuracy of the data and how to control it?

Thanks a lot !

Antony Lewis
Posts: 1941
Joined: September 23 2004
Affiliation: University of Sussex
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Re: camb: number of data points of matter power spectrum an

Post by Antony Lewis » October 28 2014

Set transfer_k_per_logint in the .ini file.

Zero is a default spacing which is quite good, though may not be accurate to better than 0.3%; increase it to get it more accurate.

(and transfer_interp_matterpower =F, as noted in the .ini if you want to interpolate later)

Pengyuan Gao
Posts: 9
Joined: September 06 2013
Affiliation: NAOC

camb: number of data points of matter power spectrum and it

Post by Pengyuan Gao » October 31 2014

Thank you very much.

What accuracy is 0.3% ? the accuracy of interpolation or just that of each data point ?

What does is mean if it is the accuracy of interpolation, because the accuracy of interpolation depends on the method of interpolation.

How to increase the accuracy of each data point calculated from camb ,please ?
The accuracy of each data point is very important to me because I need to calculate the derivative of matter power spectrum to cosmological parameters !!

Thanks again !

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