Implement simulate_error_rate.py

python/hccd/utility.py

@@ -0,0 +1,29 @@
+import numpy as np
+
+
+def _parse_alist_header(header):
+    size = header.split()
+    return int(size[0]), int(size[1])
+
+
+def read_alist_file(filename):
+    """
+    This function reads in an alist file and creates the
+    corresponding parity check matrix H. The format of alist
+    files is described at:
+    http://www.inference.phy.cam.ac.uk/mackay/codes/alist.html
+    """
+
+    with open(filename, 'r') as myfile:
+        data = myfile.readlines()
+        numCols, numRows = _parse_alist_header(data[0])
+
+        H = np.zeros((numRows, numCols))
+
+        # The locations of 1s starts in the 5th line of the file
+        for lineNumber in np.arange(4, 4 + numCols):
+            indices = data[lineNumber].split()
+            for index in indices:
+                H[int(index) - 1, lineNumber - 4] = 1
+
+        return H.astype(np.int32)