### CAMB: missing function in CAMBdata class?

Posted:

**August 12 2018**Hello everyone,

I have been using camb.get_matter_power_interpolator to obtain a 2D interpolator for the matter power spectrum, which I later use for angular galaxy overdensity power spectra.

I need to change my cosmology in order to get derivatives for Fisher matrix forecasts, so this needs to be run twice per parameter and that gets slow, so I was looking into ways to make this faster.

In the Python docs, I found the same function but from the CAMBdata class: CAMBdata.get_matter_power_interpolator, which I figured would be faster due to reusing previous calculations, but I'm getting an error that the class doesn't have that function. I'm using CAMB version 0.1.6.1.

Here is the error message I get:

Any help will be appreciated.

Felipe Maldonado

I have been using camb.get_matter_power_interpolator to obtain a 2D interpolator for the matter power spectrum, which I later use for angular galaxy overdensity power spectra.

I need to change my cosmology in order to get derivatives for Fisher matrix forecasts, so this needs to be run twice per parameter and that gets slow, so I was looking into ways to make this faster.

In the Python docs, I found the same function but from the CAMBdata class: CAMBdata.get_matter_power_interpolator, which I figured would be faster due to reusing previous calculations, but I'm getting an error that the class doesn't have that function. I'm using CAMB version 0.1.6.1.

Here is the error message I get:

Code: Select all

```
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-8-6db66903546c> in <module>()
11 results = camb.get_results(pars)
12
---> 13 interpolator = results.get_matter_power_interpolator()
AttributeError: 'CAMBdata' object has no attribute 'get_matter_power_interpolator'
CAMB version = 0.1.6.1
```

Felipe Maldonado