From f39992bda89913124c72b4252b4aac75b4e3158e Mon Sep 17 00:00:00 2001
From: Matthew Evans <7916000+ml-evs@users.noreply.github.com>
Date: Sat, 24 Jun 2023 19:15:03 +0100
Subject: [PATCH] Defer `MPRester` import to allow it to act more like an
 optional dependency (#906)

---
 matminer/featurizers/composition/thermo.py | 4 +++-
 matminer/featurizers/conversions.py        | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/matminer/featurizers/composition/thermo.py b/matminer/featurizers/composition/thermo.py
index 46ce4564a..c1dc2a358 100644
--- a/matminer/featurizers/composition/thermo.py
+++ b/matminer/featurizers/composition/thermo.py
@@ -2,7 +2,6 @@
 Composition featurizers for thermodynamic properties.
 """
 
-from pymatgen.ext.matproj import MPRester
 
 from matminer.featurizers.base import BaseFeaturizer
 from matminer.utils.data import CohesiveEnergyData
@@ -40,6 +39,8 @@ def featurize(self, comp, formation_energy_per_atom=None):
         formation_energy_per_atom = formation_energy_per_atom or None
 
         if not formation_energy_per_atom:
+            from pymatgen.ext.matproj import MPRester
+
             # Get formation energy of most stable structure from MP
             if self.mapi_key:
                 struct_lst = MPRester(self.mapi_key).get_data(comp.reduced_formula)
@@ -98,6 +99,7 @@ def featurize(self, comp):
         Args:
             comp: (str) compound composition, eg: "NaCl"
         """
+        from pymatgen.ext.matproj import MPRester
 
         # Get formation energy of most stable structure from MP
         with MPRester(self.mapi_key) if self.mapi_key else MPRester() as mpr:
diff --git a/matminer/featurizers/conversions.py b/matminer/featurizers/conversions.py
index f61135722..4d9699c0f 100644
--- a/matminer/featurizers/conversions.py
+++ b/matminer/featurizers/conversions.py
@@ -12,7 +12,6 @@
 from monty.json import MontyDecoder
 from pymatgen.core.composition import Composition
 from pymatgen.core.structure import IStructure
-from pymatgen.ext.matproj import MPRester
 from pymatgen.io.ase import AseAtomsAdaptor
 
 from matminer.featurizers.base import BaseFeaturizer
@@ -566,6 +565,9 @@ class CompositionToStructureFromMP(ConversionFeaturizer):
     """
 
     def __init__(self, target_col_id="structure", overwrite_data=False, mapi_key=None):
+
+        from pymatgen.ext.matproj import MPRester
+
         super().__init__(target_col_id, overwrite_data)
         if mapi_key:
             self.mpr = MPRester(mapi_key)