Add further LHAPDF compatibility layers

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Added further `LHAPDF` compatibility layers ([#93](https://github.com/QCDLab/neopdf/pull/93))
+
 ## [0.3.3] - 12/05/2026
 
 ### Added

docs/design-and-features.md

@@ -199,6 +199,21 @@ into diverse computational workflows:
   Key functions like `xfxQ2()`, `alphasQ2()`, and `mkPDF()` maintain the same signatures as
   LHAPDF, ensuring compatibility with existing analysis codes.
 
+The following symbols have an exact match with their LHAPDF counterparts.
+
+*Module-level:*
+`setVerbosity()`, `verbosity()`, `getPDFSet()`, `mkPDF()`, `mkPDFs()`,
+`availablePDFSets()`, `paths()`, `setPaths()`, `pathsAppend()`, `pathsPrepend()`.
+
+*`PDFSet` class:*
+`name`, `size`, `description`, `errorType`, `lhapdfID`, `mkPDF()`, `mkPDFs()`, `info()`.
+
+*`PDF` class:*
+`xfxQ()`, `xfxQ2()`, `alphasQ()`, `alphasQ2()`, `flavors()`, `hasFlavor()`,
+`inRangeX()`, `inRangeQ()`, `inRangeQ2()`, `inRangeXQ()`, `inRangeXQ2()`,
+`memberID`, `lhapdfID`, `orderQCD`, `xMin`, `xMax`, `q2Min`, `q2Max`,
+`quarkMass()`, `quarkThreshold()`, `description`, `set`.
+
 This compatibility is crucial for the physics community, as it allows for immediate adoption
 without requiring extensive code rewrites or validation efforts.
 

neopdf/src/interpolator.rs

@@ -97,18 +97,18 @@ impl InterpolationConfig {
 
         match dims {
             (false, false, false, false, false) => Self::TwoD,
-            (true, false, false, false, false) => Self::ThreeDNucleons,
-            (false, true, false, false, false) => Self::ThreeDAlphas,
-            (false, false, true, false, false) => Self::ThreeDXi,
-            (false, false, false, true, false) => Self::ThreeDDelta,
-            (false, false, false, false, true) => Self::ThreeDKt,
-            (true, true, false, false, false) => Self::FourDNucleonsAlphas,
-            (true, false, false, false, true) => Self::FourDNucleonsKt,
-            (false, true, false, false, true) => Self::FourDAlphasKt,
-            (false, false, true, true, false) => Self::FourDXiDelta,
-            (false, false, true, true, true) => Self::FiveD,
-            (true, false, true, true, true) => Self::SixD,
-            (true, true, true, true, true) => Self::SevenD,
+            (true,  false, false, false, false) => Self::ThreeDNucleons,
+            (false, true,  false, false, false) => Self::ThreeDAlphas,
+            (false, false, true,  false, false) => Self::ThreeDXi,
+            (false, false, false, true,  false) => Self::ThreeDDelta,
+            (false, false, false, false, true ) => Self::ThreeDKt,
+            (true,  true,  false, false, false) => Self::FourDNucleonsAlphas,
+            (true,  false, false, false, true ) => Self::FourDNucleonsKt,
+            (false, true,  false, false, true ) => Self::FourDAlphasKt,
+            (false, false, true,  true,  false) => Self::FourDXiDelta,
+            (false, false, true,  true,  true ) => Self::FiveD,
+            (true,  false, true,  true,  true ) => Self::SixD,
+            (true,  true,  true,  true,  true ) => Self::SevenD,
             _ => panic!(
                 "Unsupported dimension combination: nucleons={}, alphas={}, xis={}, deltas={}, kts={}",
                 n_nucleons, n_alphas, n_xis, n_deltas, n_kts

neopdf_pyapi/src/lib.rs

@@ -3,6 +3,10 @@
 #![allow(unsafe_op_in_unsafe_fn)]
 
 use pyo3::prelude::*;
+use std::sync::atomic::{AtomicI32, Ordering};
+
+use crate::pdf::{PyLoaderMethod, PyPDF, PyPDFSet};
+use ::neopdf::manage::ManageData;
 
 /// Python bindings for the `converter` module.
 pub mod converter;
@@ -21,10 +25,99 @@ pub mod uncertainty;
 /// Python bindings for the `writer` module.
 pub mod writer;
 
+static VERBOSITY: AtomicI32 = AtomicI32::new(0);
+
+/// Set the `NeoPDF` verbosity level (no-op, exists for LHAPDF API compatibility).
+#[pyfunction]
+#[pyo3(name = "setVerbosity")]
+fn set_verbosity(level: i32) {
+    VERBOSITY.store(level, Ordering::Relaxed);
+}
+
+/// Return the current verbosity level.
+#[pyfunction]
+fn verbosity() -> i32 {
+    VERBOSITY.load(Ordering::Relaxed)
+}
+
+/// Return a `PDFSet` object for the named set (LHAPDF-compatible).
+#[pyfunction]
+#[pyo3(name = "getPDFSet")]
+fn get_pdf_set(setname: &str) -> PyPDFSet {
+    PyPDFSet::new(setname)
+}
+
+/// Load a single PDF member by set name and member index (LHAPDF-compatible).
+#[pyfunction]
+#[pyo3(name = "mkPDF")]
+#[pyo3(signature = (pdf_name, member = 0))]
+fn mk_pdf(pdf_name: &str, member: usize) -> PyPDF {
+    PyPDF::new(pdf_name, member)
+}
+
+/// Load all members of a PDF set (LHAPDF-compatible).
+#[pyfunction]
+#[pyo3(name = "mkPDFs")]
+fn mk_pdfs(pdf_name: &str) -> Vec<PyPDF> {
+    PyPDF::mkpdfs(pdf_name, &PyLoaderMethod::Parallel)
+}
+
+/// Return a list of PDF set names available in the current data path.
+#[pyfunction]
+#[pyo3(name = "availablePDFSets")]
+fn available_pdf_sets() -> Vec<String> {
+    let data_path = ManageData::get_data_path();
+    let mut sets = Vec::new();
+    if let Ok(entries) = std::fs::read_dir(&data_path) {
+        for entry in entries.flatten() {
+            let path = entry.path();
+            if path.is_dir() {
+                let name = path
+                    .file_name()
+                    .unwrap_or_default()
+                    .to_string_lossy()
+                    .into_owned();
+                if path.join(format!("{name}.info")).exists() {
+                    sets.push(name);
+                }
+            }
+        }
+    }
+    sets.sort();
+    sets
+}
+
+/// Return the list of data paths searched for PDF sets.
+#[pyfunction]
+fn paths() -> Vec<String> {
+    vec![ManageData::get_data_path().to_string_lossy().into_owned()]
+}
+
+/// No-op: path management is controlled via the `NEOPDF_DATA_PATH` env var.
+#[pyfunction]
+#[pyo3(name = "setPaths")]
+fn set_paths(_paths: Vec<String>) {}
+
+/// No-op: path management is controlled via the `NEOPDF_DATA_PATH` env var.
+#[pyfunction]
+#[pyo3(name = "pathsAppend")]
+fn paths_append(_path: String) {}
+
+/// No-op: path management is controlled via the `NEOPDF_DATA_PATH` env var.
+#[pyfunction]
+#[pyo3(name = "pathsPrepend")]
+fn paths_prepend(_path: String) {}
+
+/// Return the NeoPDF version string (LHAPDF-compatible callable).
+#[pyfunction]
+fn version() -> &'static str {
+    env!("CARGO_PKG_VERSION")
+}
+
 /// `PyO3` Python module that contains all exposed classes from Rust.
 #[pymodule]
 fn neopdf(m: &Bound<'_, PyModule>) -> PyResult<()> {
-    m.add("version", env!("CARGO_PKG_VERSION"))?;
+    m.add("__version__", env!("CARGO_PKG_VERSION"))?;
     pdf::register(m)?;
     metadata::register(m)?;
     converter::register(m)?;
@@ -33,5 +126,16 @@ fn neopdf(m: &Bound<'_, PyModule>) -> PyResult<()> {
     parser::register(m)?;
     writer::register(m)?;
     uncertainty::register(m)?;
+    m.add_function(wrap_pyfunction!(set_verbosity, m)?)?;
+    m.add_function(wrap_pyfunction!(verbosity, m)?)?;
+    m.add_function(wrap_pyfunction!(get_pdf_set, m)?)?;
+    m.add_function(wrap_pyfunction!(mk_pdf, m)?)?;
+    m.add_function(wrap_pyfunction!(mk_pdfs, m)?)?;
+    m.add_function(wrap_pyfunction!(available_pdf_sets, m)?)?;
+    m.add_function(wrap_pyfunction!(paths, m)?)?;
+    m.add_function(wrap_pyfunction!(set_paths, m)?)?;
+    m.add_function(wrap_pyfunction!(paths_append, m)?)?;
+    m.add_function(wrap_pyfunction!(paths_prepend, m)?)?;
+    m.add_function(wrap_pyfunction!(version, m)?)?;
     Ok(())
 }

neopdf_pyapi/src/manage.rs

@@ -3,7 +3,7 @@ use pyo3::exceptions::PyRuntimeError;
 use pyo3::prelude::*;
 
 /// Python wrapper for the `PdfSetFormat` enum.
-#[pyclass(name = "PdfSetFormat")]
+#[pyclass(from_py_object, name = "PdfSetFormat")]
 #[derive(Clone)]
 pub enum PyPdfSetFormat {
     /// LHAPDF format (standard PDF set format used by LHAPDF).

neopdf_pyapi/src/metadata.rs

@@ -3,7 +3,7 @@ use pyo3::prelude::*;
 use neopdf::metadata::{InterpolatorType, MetaData, SetType};
 
 /// The type of the set.
-#[pyclass(eq, eq_int, name = "SetType")]
+#[pyclass(eq, eq_int, from_py_object, name = "SetType")]
 #[derive(Clone, PartialEq, Eq)]
 pub enum PySetType {
     /// Parton Distribution Function.
@@ -31,7 +31,7 @@ impl From<&PySetType> for SetType {
 }
 
 /// The interpolation method used for the grid.
-#[pyclass(eq, eq_int, name = "InterpolatorType")]
+#[pyclass(eq, eq_int, from_py_object, name = "InterpolatorType")]
 #[derive(Clone, PartialEq, Eq)]
 pub enum PyInterpolatorType {
     /// Bilinear interpolation strategy.
@@ -83,7 +83,7 @@ impl From<&PyInterpolatorType> for InterpolatorType {
 }
 
 /// Physical Parameters of the PDF set.
-#[pyclass(name = "PhysicsParameters")]
+#[pyclass(from_py_object, name = "PhysicsParameters")]
 #[derive(Debug, Clone)]
 pub struct PyPhysicsParameters {
     pub(crate) flavor_scheme: String,
@@ -198,7 +198,7 @@ impl Default for PyPhysicsParameters {
 }
 
 /// Grid metadata.
-#[pyclass(name = "MetaData")]
+#[pyclass(from_py_object, name = "MetaData")]
 #[derive(Debug, Clone)]
 #[repr(transparent)]
 pub struct PyMetaData {