BUG: Fix index error when values exceed 999T (#581)

* fix IndexError when values exceed 999T in _human_format function

Signed-off-by: Fabian Degen <fabian.degen@mytum.de>

* add testcase to test _human_format function with numbers larger 999T

Signed-off-by: Fabian Degen <fabian.degen@mytum.de>

* fix ruff format

Signed-off-by: Fabian Degen <fabian.degen@mytum.de>

---------

Signed-off-by: Fabian Degen <fabian.degen@mytum.de>
Co-authored-by: Fabian Degen <fabian.degen@mytum.de>

python/interpret-core/interpret/visual/plot.py

@@ -203,15 +203,19 @@ def extend_y_range(y):
 
 # Taken from:
 # https://stackoverflow.com/questions/579310/formatting-long-numbers-as-strings-in-python
+# Adapted to handle numbers larger than 1e15
 def _human_format(num):
     num = float(f"{num:.3g}")
     magnitude = 0
+    suffixes = ["", "K", "M", "B", "T"]
+
+    if abs(num) >= 1000 ** (len(suffixes)):  # 1000 ^ 5 == 1e15
+        return f"{num:.2e}"
+
     while abs(num) >= 1000:
         magnitude += 1
         num /= 1000.0
-    return "{}{}".format(
-        f"{num:f}".rstrip("0").rstrip("."), ["", "K", "M", "B", "T"][magnitude]
-    )
+    return "{}{}".format(f"{num:f}".rstrip("0").rstrip("."), suffixes[magnitude])
 
 
 # TODO: Clean this up after validation.

python/interpret-core/tests/visual/test_plot.py

@@ -2,6 +2,7 @@
 # Distributed under the MIT software license
 
 from interpret.visual.plot import plot_line
+from interpret.visual.plot import plot_density
 
 
 def test_plot_line_bounds_smoke():
@@ -13,3 +14,19 @@ def test_plot_line_bounds_smoke():
     }
     figure = plot_line(data_dict)
     assert figure.data[0].name == "Lower Bound"
+
+
+def test_plot_density_large_numbers():
+    """
+    Test that density plots handle large numbers correctly using the new number formatting
+    """
+    data_dict = {
+        "scores": [1.0, 1.0],
+        "names": [9e13, 1e14, 1e15],  # 1e15 value will trigger new formatting
+    }
+
+    figure = plot_density(data_dict)
+
+    # The x-axis tick text should show ranges using our new formatting
+    assert "90T - 100T" in figure.layout.xaxis.ticktext[0]
+    assert "100T - 1.00e+15" in figure.layout.xaxis.ticktext[1]