Added Confusion matrix

.gitignore

@@ -7,3 +7,4 @@ engineering.ipynb
 images/*_latex.png
 images/*_python.png
 *.drawio
+.virtual_documents/

README.md

@@ -46,6 +46,17 @@ The `plotLaTeX` package is a recent project to make exporting Python data to a L
     <img src="images/example_scatter.png" alt="Fig8" width="1000px">
 </p>
 
+**[Scatterplot](examples/ScatterPlot.ipynb)**
+
+<p align="center">
+    <img src="images/example_scatter.png" alt="Fig8" width="1000px">
+</p>
+
+**[Confusion Matrix](examples/ConfusionMatrix.ipynb)**
+
+<p align="center">
+    <img src="images/example_cm.png" alt="Fig9" width="1000px">
+</p>
 
 **TBD**
 

examples/BarPlot.ipynb

@@ -524,7 +524,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.2"
+   "version": "3.11.14"
   }
  },
  "nbformat": 4,

plotLaTeX/__init__.py

@@ -4,6 +4,7 @@
 from .bar_plot import Barplot, MultipleBars
 from .stem_plot import StemPlot
 from .scatter_plot import ScatterPlot
+from .confusionmatrix import ConfusionMatrix
 
 __all__ = [
     "LaTeXplot",
@@ -13,4 +14,5 @@
     "MultipleBars",
     "StemPlot",
     "ScatterPlot",
+    "ConfusionMatrix",
 ]

plotLaTeX/confusionmatrix.py

@@ -0,0 +1,183 @@
+import numpy as np
+
+
+class ConfusionMatrix:
+    """
+    Convert a confusion matrix into TikZ/pgfplots 'matrix plot' code
+    WITHOUT exporting a CSV (values are embedded inline).
+    """
+
+    def __init__(self, cm=None, labels=None):
+        self.cm = None
+        self.labels = None
+        self.n_classes = None
+
+        if cm is not None and labels is not None:
+            self.from_confusion_matrix(cm, labels)
+
+    def from_confusion_matrix(self, cm: np.ndarray, labels):
+        cm = np.asarray(cm)
+        if cm.ndim != 2 or cm.shape[0] != cm.shape[1]:
+            raise ValueError(f"cm must be a square 2D array. Got shape {cm.shape}.")
+        if len(labels) != cm.shape[0]:
+            raise ValueError(
+                f"labels length must match cm size. Got {len(labels)} vs {cm.shape[0]}."
+            )
+
+        self.cm = cm.astype(float)
+        self.labels = list(labels)
+        self.n_classes = cm.shape[0]
+        return self
+
+    def from_y(self, y_true, y_pred, labels=None):
+        from sklearn.metrics import confusion_matrix
+
+        cm = confusion_matrix(y_true, y_pred, labels=labels)
+        if labels is None:
+            uniq = np.unique(np.concatenate([np.asarray(y_true), np.asarray(y_pred)]))
+            labels = list(uniq)
+        return self.from_confusion_matrix(cm, labels)
+
+    @staticmethod
+    def _escape_tex(s: str) -> str:
+        repl = {
+            "\\": r"\textbackslash{}",
+            "&": r"\&",
+            "%": r"\%",
+            "$": r"\$",
+            "#": r"\#",
+            "_": r"\_",
+            "{": r"\{",
+            "}": r"\}",
+            "~": r"\textasciitilde{}",
+            "^": r"\textasciicircum{}",
+        }
+        out = str(s)
+        for k, v in repl.items():
+            out = out.replace(k, v)
+        return out
+
+    def _long_rows(self, normalize=True, decimals=2):
+        """
+        Returns rows: (x, y, C) where:
+          x = predicted class index
+          y = true class index
+          C = value (percent or count)
+        """
+        if self.cm is None:
+            raise RuntimeError(
+                "No confusion matrix loaded. Call from_confusion_matrix(...) or from_y(...)."
+            )
+
+        cm = self.cm.copy()
+        if normalize:
+            total = cm.sum()
+            cm = (cm / total) * 100.0 if total > 0 else np.zeros_like(cm)
+
+        cm = np.round(cm, decimals)
+
+        rows = []
+        for y in range(self.n_classes):
+            for x in range(self.n_classes):
+                rows.append((x, y, float(cm[y, x])))
+        return rows
+
+    def tikz(
+        self,
+        xlabel="Predicted material",
+        ylabel="True material",
+        width="5cm",
+        height="5cm",
+        colormap_name="blue",
+        normalize=True,
+        decimals=2,
+        draw_color="gray",
+        point_meta_min=0.0,
+        point_meta_max=100.0,
+        show_percent_node=True,
+        percent_node_pos=(5.1, 1.55),
+    ) -> str:
+        """
+        Generate TikZ/pgfplots code (inline table), matching your style.
+        """
+        if self.labels is None or self.n_classes is None:
+            raise RuntimeError("No labels/classes loaded.")
+
+        xticklabels = ", ".join(self._escape_tex(l) for l in self.labels)
+        yticklabels = ", ".join(self._escape_tex(l) for l in self.labels)
+
+        n = self.n_classes
+        tick_range = f"0,...,{n-1}"
+
+        rows = self._long_rows(normalize=normalize, decimals=decimals)
+
+        # Inline table body
+        table_lines = ["x y C"]
+        for x, y, c in rows:
+            table_lines.append(f"{x} {y} {c}")
+
+        table_block = "\n\t\t\t" + "\n\t\t\t".join(table_lines)
+
+        lines = []
+        lines.append("% imports")
+        lines.append("\\usepackage{tikz}")
+        lines.append("\\usepackage{pgfplots}")
+        lines.append("\\pgfplotsset{compat=1.18}")
+        lines.append(
+            "\\usetikzlibrary{shapes,positioning,fit,arrows.meta,decorations.pathreplacing}"
+        )
+        lines.append("")
+        lines.append("\\begin{tikzpicture}[]")
+        lines.append("	\\begin{axis}[")
+        lines.append(f"		width={width},")
+        lines.append(f"		height={height},")
+        lines.append(f"		colormap={{{colormap_name}}}{{color=(white) color=(blue)}},")
+        lines.append(f"		xticklabels={{{xticklabels}}},")
+        lines.append(f"		xtick={{{tick_range}}},")
+        lines.append("		xtick style={draw=none},")
+        lines.append(f"		yticklabels={{{yticklabels}}},")
+        lines.append(f"		ytick={{{tick_range}}},")
+        lines.append("		ytick style={draw=none},")
+        lines.append(f"		xlabel={{{self._escape_tex(xlabel)}}},")
+        lines.append(f"		ylabel={{{self._escape_tex(ylabel)}}},")
+        lines.append("		enlargelimits=false,")
+        lines.append("		colorbar,")
+        lines.append("		colorbar style={")
+        lines.append(
+            "			plot graphics/node/.style={scale=1.33,anchor=south west,inner sep=0pt,},"
+        )
+        lines.append("			ytick={0,20,40,60,80,100},")
+        lines.append("			yticklabels={0,0.2,0.4,0.6,0.8,1.0},")
+        lines.append("			yticklabel={\\pgfmathprintnumber\\tick},")
+        lines.append("			yticklabel style={")
+        lines.append("				/pgf/number format/fixed,")
+        lines.append("				/pgf/number format/precision=1}")
+        lines.append("		},")
+        lines.append(
+            f"		point meta min={point_meta_min},point meta max={point_meta_max},"
+        )
+        lines.append("		nodes near coords={\\pgfmathprintnumber\\pgfplotspointmeta},")
+        lines.append("		nodes near coords style={")
+        lines.append("			yshift=-7pt,")
+        lines.append("			/pgf/number format/fixed,")
+        lines.append(f"			/pgf/number format/precision={int(decimals)}}},")
+        lines.append("		]")
+        lines.append("		\\addplot[")
+        lines.append("			matrix plot,")
+        lines.append(f"			mesh/cols={n},")
+        lines.append(f"			point meta=explicit,draw={draw_color}")
+        lines.append("		] table [meta=C] {")
+        lines.append(table_block)
+        lines.append("		};")
+        lines.append("	\\end{axis}")
+
+        if show_percent_node:
+            x0, y0 = percent_node_pos
+            lines.append("")
+            lines.append(
+                f"	\\node [align=right, anchor = south] at ({x0},{y0}) {{\\footnotesize{{\\%}}}};"
+            )
+
+        lines.append("\\end{tikzpicture}")
+
+        return "\n".join(lines)