Isolate the PDF interpolation backend to support both LHAPDF and NeoPDF

.github/workflows/rust.yml

@@ -35,6 +35,7 @@ jobs:
           # `-C link-dead-code` is needed to prevent 'warning: XX functions have mismatched data' warnings
           RUSTFLAGS: '-Cinstrument-coverage -Clink-dead-code'
         run: |
+          export NEOPDF_DATA_PATH=/usr/local/share/LHAPDF
           # we need stderr, but we can't run test twice because it'll regenerate/modify the binaries which interferes with `llvm-cov`
           cargo test --features=applgrid,evolve,fastnlo,fktable --no-fail-fast 2> >(tee stderr 1>&2)
           # from https://stackoverflow.com/a/51141872/812178

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- added support for the [NeoPDF](https://qcdlab.github.io/neopdf/) library as
+  an alternative to LHAPDF in the CLI; using `--backend=neopdf` one can use it.
+
 ## [1.4.0] - 12/05/2026
 
 Starting with this version, PineAPPL has an official logo!

Cargo.toml

@@ -35,11 +35,12 @@ enum_dispatch = "0.3.7"
 flate2 = "1.0.22"
 float-cmp = { default-features = false, version = "0.10.0" }
 git-version = "0.3.5"
-itertools = "0.14.0"
+itertools = "0.13.0"
 lhapdf = { package = "managed-lhapdf", version = "0.4.1" }
 lz4_flex = "0.13.0"
 ndarray = { version = "0.17.2" }
 ndarray-npy = { default-features = false, features = ["npz"], version = "0.10.0" }
+neopdf = { git = "https://github.com/QCDLab/neopdf.git" }
 num-complex = "0.4.4"
 numpy = "0.28.0"
 pkg-config = "0.3.26"

README.md

@@ -45,14 +45,16 @@ If you use PineAPPL, please cite
 By using PineAPPL, you're probably also using
 
 - [APPLgrid],
-- [fastNLO] and/or
+- [fastNLO],
+- [NeoPDF] and/or
 - [LHAPDF].
 
 If that is the case, please cite these accordingly.
 
 [APPLgrid]: https://applgrid.hepforge.org
 [fastNLO]: https://fastnlo.hepforge.org
 [LHAPDF]: https://lhapdf.hepforge.org
+[NeoPDF]: https://qcdlab.github.io/neopdf/
 [zenodo DOI]: https://zenodo.org/badge/latestdoi/248306479
 [paper]: https://inspirehep.net/literature/1814432
 

pineappl_cli/Cargo.toml

@@ -30,6 +30,7 @@ lhapdf.workspace = true
 lz4_flex = { optional = true, workspace = true }
 ndarray.workspace = true
 ndarray-npy = { optional = true, workspace = true }
+neopdf.workspace = true
 pineappl.workspace = true
 pineappl_applgrid = { optional = true, workspace = true }
 pineappl_fastnlo = { optional = true, workspace = true }