Add trace transform function.

2 files changed, 30 insertions, 0 deletions

diff --git a/pyecsca/sca/trace/process.py b/pyecsca/sca/trace/process.py
index bc5b8dd..92a6296 100644
--- a/pyecsca/sca/trace/process.py
+++ b/pyecsca/sca/trace/process.py
@@ -1,4 +1,5 @@
 """Provides functions for sample-wise processing of single traces."""
+from typing import Any
 
 import numpy as np
 from scipy.signal import convolve
@@ -113,3 +114,20 @@ def normalize_wl(trace: Trace) -> Trace:
         (trace.samples - np.mean(trace.samples))
         / (np.std(trace.samples) * len(trace.samples))
     )
+
+
+@public
+def transform(trace: Trace, min_value: Any = 0, max_value: Any = 1) -> Trace:
+    """
+    Scale a :paramref:`~.transform.trace` so that its minimum is at :paramref:`~.transform.min_value` and its maximum is at :paramref:`~.transform.max_value`.
+
+    :param trace:
+    :param min_value:
+    :param max_value:
+    :return:
+    """
+    t_min = np.min(trace.samples)
+    t_max = np.max(trace.samples)
+    t_range = t_max - t_min
+    d = max_value - min_value
+    return trace.with_samples(((trace.samples - t_min) * (d/t_range)) + min_value)
diff --git a/test/sca/test_process.py b/test/sca/test_process.py
index 9ab8bcf..e36f212 100644
--- a/test/sca/test_process.py
+++ b/test/sca/test_process.py
@@ -11,6 +11,7 @@ from pyecsca.sca import (
     recenter,
     normalize,
     normalize_wl,
+    transform
 )
 
 
@@ -62,8 +63,19 @@ def test_recenter(trace):
 def test_normalize(trace):
     result = normalize(trace)
     assert result is not None
+    assert np.isclose(0, np.mean(result.samples))
+    assert np.isclose(1, np.var(result.samples))
 
 
 def test_normalize_wl(trace):
     result = normalize_wl(trace)
     assert result is not None
+    assert np.isclose(0, np.mean(result.samples))
+    assert np.isclose(1/len(result), np.std(result.samples))
+
+
+def test_transform(trace):
+    result = transform(trace, 5, 10)
+    assert result is not None
+    assert min(result) == 5
+    assert max(result) == 10