[CLN] Refactor Sections class and imports for clarity

Simplified imports and removed unused `SectionDefinition` class. Adjusted and clarified type annotations while ensuring internal fields are properly excluded from serialization.

gempy/core/data/grid_modules/sections_grid.py

@@ -4,25 +4,16 @@
 import dataclasses
 import numpy as np
 
-from gempy.core.data.core_utils import calculate_line_coordinates_2points
-from gempy.optional_dependencies import require_pandas
+from ..core_utils import calculate_line_coordinates_2points
+from ..encoders.converters import short_array_type
+from ....optional_dependencies import require_pandas
 
 try:
    import pandas as pd
 except ImportError:
    pandas = None
 
 
-@dataclasses.dataclass
-class SectionDefinition:
-    """
-    A single cross‐section’s raw parameters.
-    """
-    start: Tuple[float, float]
-    stop: Tuple[float, float]
-    resolution: Tuple[int, int]
-
-
 @dataclasses.dataclass
 class Sections:
     """
@@ -40,18 +31,25 @@ class Sections:
 
     # user‐provided inputs
 
-    z_ext: Tuple[float, float]
-    section_dict: Dict[str, tuple[list[int]]]
+    z_ext: Tuple[float, float] | short_array_type
+    section_dict: Dict[
+        str,
+        Tuple[
+            Tuple[float, float],  # start
+            Tuple[float, float],  # stop
+            Tuple[int,   int]     # resolution
+        ]
+    ]
 
     # computed/internal (will be serialized too unless excluded)
-    names: List[str] = Field(default_factory=list)
-    points: List[List[Tuple[float, float]]] = Field(default_factory=list)
-    resolution: List[Tuple[int, int]] = Field(default_factory=list)
-    length: np.ndarray = Field(default_factory=lambda: np.array([0]), exclude=False)
-    dist: np.ndarray = Field(default_factory=lambda: np.array([]), exclude=False)
-    df: Optional[pd.DataFrame] = Field(default_factory=None, exclude=False)
-    values: np.ndarray = Field(default_factory=lambda: np.empty((0, 3)), exclude=False)
-    extent: Optional[np.ndarray] = None
+    names: List[str] = Field(default_factory=list, exclude=True)
+    points: List[List[Tuple[float, float]]] = Field(default_factory=list, exclude=True)
+    resolution: List[Tuple[int, int]] = Field(default_factory=list, exclude=True)
+    length: np.ndarray = Field(default_factory=lambda: np.array([0]), exclude=True)
+    dist: np.ndarray = Field(default_factory=lambda: np.array([]), exclude=True)
+    df: Optional[pd.DataFrame] = Field(default=None, exclude=True)
+    values: np.ndarray = Field(default_factory=lambda: np.empty((0, 3)), exclude=True)
+    extent: Optional[np.ndarray] = Field(default=None, exclude=True)
 
     # def __init__(self, regular_grid=None, z_ext=None, section_dict=None):
     #     pd = require_pandas()
@@ -75,12 +73,13 @@ class Sections:
     #         self.set_sections(section_dict)
     def __post_init__(self):
         self.initialize_computations()
+        pass
 
     # @model_validator(mode="after")
     # def init_class(self):
     #     self.initialize_computations()
     #     return self
-
+    # 
     def initialize_computations(self):
         # copy names
         self.names = list(self.section_dict.keys())