delensalot

Curved-sky optimal CMB lensing reconstruction and bias calculation. Delensalot, in essence, takes an observed CMB map and returns an optimal estimate of the underlying lensing field.

If you use delensalot for your work, please consider citing the ApJ publication CMB-S4: Iterative internal delensing and r constraints.

This figure shows the full sky optimal lensing potential reconstruction for various CMB observations in a 5 times 5 degree patch. The input lensing potential is shown in the leftmost figure.

Features and supports

• Curved-sky analysis
• anisotropic noise model support
• masked-sky support
• quadratic estimator (QE) implementation via Plancklens
• Mock data generation using e.g. lenspyx
• Supports various estimators (TT, EE, BB, MV, EE+EB, ..)

Installation

Download the project, navigate to the root folder and execute the command,

python setup.py install

Make sure that you have the latest plancklens and lenpsyx.

Set up a jupyter-kernel with delensalot

You will need to install jupyter for the tutorials found in first_steps/notebooks/, and possibly an ipykernel to create a jupyter-kernel out of the environment in which you install delensalot. To run the tutorials with a jupyter kernel, you will have to install delensalot in it. Assuming you are using conda for your package management,

conda create --name delensalot
conda activate delensalot

Then, install your favourite packages,

conda install pip, numpy

Now, go to the delensalot directory, and install, including its requirements,

cd </path/to/delensalot>
python3 -m pip install -r requirements .
python3 setup.py develop

Eventually, create your kernel using the environment at which you just installed all packages,

python3 -m ipykernel install --user --name=delensalot

Installation troubles

Frequent problems are

• attrs. If there are errors related to the metamodel, make sure you have attrs (not attr, which is a different package) installed and updated/upgraded (version 23.1.0 should do)
• astropy. If there are errors related to ducc0, chances are it's because of an old astropy installation.

Usage

parameter file

Check the first_steps/parameter_files/ and run any of them using,

python3 <parfile>.py

Run a configuration file

To run a configuration file <path-to-config/conf.py>, type in your favorite bash,

python3 run.py -r <path-to-config/conf.py>

delensalot supports MPI,

srun --nodes <nnodes> -n <taskspernode> python3 run.py -r <path-to-config/conf.py>

interactive mode

delensalot supports interactive mode. See first_steps/notebooks/ for our tutorials.

help

Type python3 run.py [-h] for quickhelp,

usage: run.py [-h] [-p NEW] [-r RESUME] [-s STATUS] [-purgehashs PURGEHASHS]

delensalot entry point.

optional arguments:
  -h, --help            show this help message and exit
  -r RESUME             Absolute path to config file to run/resume.
  -s STATUS             Absolute path for the analysis to write a report.

Dependencies

uses

• Plancklens
• lenspyx
• DUCC

Doc

Documentation may be found [HERE]

Use with HPC

delensalot can be computationally demanding. We have parallelized the computations across the simulation index in most cases. Assuming you have MPI set up and srun is available, you can simply run MPI-supported delensalot via,

srun -MPI_paramX X -MPI_paramY Y python3 <path-to-delensalot>/run.py -r <path-to-config-file>

If you have troubles, your HPC-center can help.