X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=matrices.py;h=60db346a0a966ed6b686d9c368f3e2b18eb6a73d;hb=a874fc5af210e969c3191e74a4bf0b4301894df2;hp=01ab35274ed2157cac71af13dd84b0fdf3e4dfd4;hpb=91660cdf9b0662f4d7f1d9ecea516dfea010a729;p=dunshire.git

diff --git a/matrices.py b/matrices.py
index 01ab352..60db346 100644
--- a/matrices.py
+++ b/matrices.py
@@ -1,4 +1,5 @@
 from cvxopt import matrix, spmatrix
+from math import sqrt
 
 def append_col(A,b):
     """
@@ -6,21 +7,6 @@ def append_col(A,b):
     """
     return matrix([A.trans(),b.trans()]).trans()
 
-def append_cols(cols):
-    """
-    Append a bunch of columns together, left to right.
-    """
-    if len(cols) == 0:
-        return cols
-
-    result = cols[0]
-    del(cols[0])
-    for column in cols:
-        result = append_col(result, column)
-
-    return result
-
-
 def append_row(A,b):
     """
     Append the row ``b`` to the bottom of the matrix ``A``.
@@ -32,3 +18,9 @@ def identity(n):
     Return the ``n``-by-``n`` identity matrix.
     """
     return spmatrix(1,range(n),range(n))
+
+def norm(x):
+    """
+    Return the Euclidean norm of the given vector.
+    """
+    return sqrt(sum([z**2 for z in x]))