Update app.py

app.py

@@ -97,9 +97,12 @@ def apply_dim_red(df, use, method='PCA'):
     if method == 'PCA':
         pc = PCA(n_components=2).fit_transform(X)
     elif method == 'UMAP':
-        pc = UMAP(n_components=2, random_state=42).fit_transform(X)
+        n_neighbors = min(15, X.shape[0]-1) if X.shape[0] > 1 else 1
+        pc = UMAP(n_components=2, random_state=42, n_neighbors=n_neighbors).fit_transform(X)
     elif method == 'tSNE':
-        pc = TSNE(n_components=2, random_state=42).fit_transform(X)
+        n_samples = X.shape[0]
+        perplexity = min(30, max(2, (n_samples-1)//2))
+        pc = TSNE(n_components=2, perplexity=perplexity, random_state=42).fit_transform(X)
     else:
         raise ValueError('Unknown method')
     return pc