build: move umap-learn into optional notebook dependencies

Except for notebooks, it's only used to show embedding plots during speaker
encoder training, in which case a warning is now shown to install it.

TTS/bin/train_encoder.py

@@ -6,6 +6,7 @@ import os
 import sys
 import time
 import traceback
+import warnings
 
 import torch
 from torch.utils.data import DataLoader
@@ -116,11 +117,14 @@ def evaluation(model, criterion, data_loader, global_step):
     eval_avg_loss = eval_loss / len(data_loader)
     # save stats
     dashboard_logger.eval_stats(global_step, {"loss": eval_avg_loss})
-    # plot the last batch in the evaluation
-    figures = {
-        "UMAP Plot": plot_embeddings(outputs.detach().cpu().numpy(), c.num_classes_in_batch),
-    }
-    dashboard_logger.eval_figures(global_step, figures)
+    try:
+        # plot the last batch in the evaluation
+        figures = {
+            "UMAP Plot": plot_embeddings(outputs.detach().cpu().numpy(), c.num_classes_in_batch),
+        }
+        dashboard_logger.eval_figures(global_step, figures)
+    except ImportError:
+        warnings.warn("Install the `umap-learn` package to see embedding plots.")
     return eval_avg_loss
 
 

TTS/encoder/utils/visual.py

@@ -1,7 +1,6 @@
 import matplotlib
 import matplotlib.pyplot as plt
 import numpy as np
-import umap
 
 matplotlib.use("Agg")
 
@@ -30,6 +29,10 @@ colormap = (
 
 
 def plot_embeddings(embeddings, num_classes_in_batch):
+    try:
+        import umap
+    except ImportError as e:
+        raise ImportError("Package not installed: umap-learn") from e
     num_utter_per_class = embeddings.shape[0] // num_classes_in_batch
 
     # if necessary get just the first 10 classes

pyproject.toml

@@ -58,8 +58,6 @@ dependencies = [
     "packaging>=23.1",
     # Inference
     "pysbd>=0.3.4",
-    # Notebooks
-    "umap-learn>=0.5.1",
     # Training
     "matplotlib>=3.7.0",
     # Coqui stack
@@ -100,6 +98,7 @@ docs = [
 notebooks = [
     "bokeh==1.4.0",
     "pandas>=1.4,<2.0",
+    "umap-learn>=0.5.1",
 ]
 # For running the TTS server
 server = ["flask>=2.0.1"]