Feat/make matplotlib optional

python/quantum-pecos/pyproject.toml

@@ -33,7 +33,6 @@ dependencies = [
     "numpy>=1.15.0",
     "scipy>=1.1.0",
     "networkx>=2.1.0",
-    "matplotlib>=2.2.0",
 ]
 classifiers = [
     "Development Status :: 4 - Beta",
@@ -61,6 +60,7 @@ guppy = [
     "selene-sim~=0.2.0",  # Then selene-sim (dependency of guppylang)
 ]
 visualization = [
+    "matplotlib>=2.2.0",
     "plotly~=5.9.0",
 ]
 all = [

python/quantum-pecos/src/pecos/qeccs/plot.py

@@ -21,9 +21,9 @@
 from typing import TYPE_CHECKING, TypeVar
 
 import networkx as nx
-from matplotlib import pyplot as plt
 
 if TYPE_CHECKING:
+
     from pecos.protocols import LogicalInstructionProtocol, QECCProtocol
 
 T = TypeVar("T")
@@ -54,6 +54,8 @@ def plot_qecc(
         **kwargs: Additional keyword arguments (will raise exception if any are provided).
 
     """
+    from matplotlib import pyplot as plt
+
     if kwargs:
         msg = f"keys {kwargs.keys()} not recognized!"
         raise Exception(msg)
@@ -166,6 +168,8 @@ def plot_instr(
         **kwargs: Additional keyword arguments (will raise exception if any are provided)
 
     """
+    from matplotlib import pyplot as plt
+
     if kwargs:
         msg = f"keys {kwargs.keys()} not recognized!"
         raise Exception(msg)

python/quantum-pecos/src/pecos/qeclib/color488/plot_layout.py

@@ -13,10 +13,11 @@
 
 from typing import TYPE_CHECKING
 
-import matplotlib.pyplot as plt
 import networkx as nx
+from matplotlib import pyplot as plt
 
 if TYPE_CHECKING:
+
     from pecos.qeclib.color488 import Color488
 
 
@@ -36,6 +37,8 @@ def plot_layout(
     Returns:
         The matplotlib pyplot module with the plot rendered.
     """
+    import matplotlib.pyplot as plt
+
     positions, polygons = color488.get_layout()
 
     # Calculate the mid-point for each polygon

python/quantum-pecos/src/pecos/qeclib/surface/visualization/lattice_2d.py

@@ -5,12 +5,12 @@
 from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
-import matplotlib.pyplot as plt
 import numpy as np
-from matplotlib.patches import Circle, PathPatch
-from matplotlib.path import Path
 
 if TYPE_CHECKING:
+    from matplotlib import pyplot as plt
+    from matplotlib.path import Path
+
     from pecos.qeclib.surface.patches.patch_base import SurfacePatch
 
 
@@ -75,6 +75,9 @@ def plot_colored_polygons(
         polygon_colors (dict[int, int]): List of indices into `colors` for each polygon.
         config (Lattice2DConfig | None): Optional Lattice2DConfig object.
     """
+    import matplotlib.pyplot as plt
+    from matplotlib.patches import Circle, PathPatch
+
     c = config
 
     # Plot setup
@@ -208,6 +211,8 @@ def create_cup_path(
     Returns:
         Path: A matplotlib path representing the cup shape.
     """
+    from matplotlib.path import Path
+
     # Calculate midpoint of the base
     mid_base = ((base1[0] + base2[0]) / 2, (base1[1] + base2[1]) / 2)
 

python/quantum-pecos/src/pecos/tools/pseudo_threshold_tools.py

@@ -22,7 +22,6 @@
 
 from typing import TYPE_CHECKING
 
-import matplotlib.pyplot as plt
 import numpy as np
 from scipy.optimize import brentq, curve_fit, newton
 
@@ -324,6 +323,8 @@ def plot(
         p_start(float): Starting point for the plot axes. If None, automatically determined.
         p_end(float): Ending point for the plot axes. If None, automatically determined.
     """
+    import matplotlib.pyplot as plt
+
     if p_start is None:
         p_start = min(plog) * 0.9
 

python/quantum-pecos/tests/conftest.py

@@ -11,11 +11,15 @@
 
 """Test configuration and shared fixtures."""
 
-# Configure matplotlib to use non-interactive backend for tests
+# Configure matplotlib to use non-interactive backend for tests (if available)
 # This must be done before importing matplotlib.pyplot to avoid GUI backend issues on Windows
-import matplotlib as mpl
+try:
+    import matplotlib as mpl
 
-mpl.use("Agg")
+    mpl.use("Agg")
+except ImportError:
+    # matplotlib is optional - only needed for visualization tests
+    pass
 
 # Note: llvmlite functionality is now always available via Rust (pecos_rslib.ir and pecos_rslib.binding)
 # No need for conditional test skipping

ruff.toml

@@ -200,6 +200,10 @@ ignore = [
 "python/quantum-pecos/src/pecos/frontends/*.py" = ["PLC0415"]  # All frontends have optional dependencies
 "python/quantum-pecos/src/pecos/frontends/guppy_frontend.py" = ["PLC0415", "S603", "S607"]  # Also uses subprocess for external tools
 "python/quantum-pecos/src/pecos/frontends/selene_native_backend.py" = ["S311"]  # Uses random for test placeholders
+"python/quantum-pecos/src/pecos/qeccs/plot.py" = ["PLC0415"]  # matplotlib: optional visualization dependency
+"python/quantum-pecos/src/pecos/qeclib/color488/plot_layout.py" = ["PLC0415"]  # matplotlib: optional visualization dependency
+"python/quantum-pecos/src/pecos/qeclib/surface/visualization/lattice_2d.py" = ["PLC0415"]  # matplotlib: optional visualization dependency
+"python/quantum-pecos/src/pecos/tools/pseudo_threshold_tools.py" = ["PLC0415"]  # matplotlib: optional visualization dependency
 
 # Examples - relaxed rules for demonstration code
 "python/pecos-rslib/examples/*.py" = ["PLC0415", "INP001"]  # Lazy imports, no __init__.py needed