Changeset 7409:dd3e113563fb

Timestamp:

11/24/07 10:30:36 (5 years ago)

Author:

William Stein <wstein@…>

Branch:

default

Message:

Slightly change behavior of hadamard_matrix in case the matrix isn't implemented or doesn't exist.

File:

• sage/combinat/combinat.py (modified) (2 diffs)

sage/combinat/combinat.py

@@ -211 +211 @@
 def hadamard_matrix(n):
     """
-    Returns an nxn Hadamard matrix of order if the construction
-    is implemented in GUAVA. 
+    Returns an n x n Hadamard matrix of order $n$, if possible.
+
+    If the construction of this matrix is not implemented in GUAVA or there is
+    no such matrix, raises a NotImplementedError.
 
     EXAMPLES:
@@ -221 +223 @@
         [ 1 -1 -1  1]
         sage: hadamard_matrix(6)
-        Hadamard matrix of order  6  does not exist or is not implemented yet.
-
+        Traceback (most recent call last):
+        ...
+        NotImplementedError: Hadamard matrix of order 6 does not exist or is not implemented yet.
     """
     try:
-       ans = gap("HadamardMat(%s)"%ZZ(n))
-       return ans._matrix_(ZZ)
+        ans = gap("HadamardMat(%s)"%ZZ(n))
+        return ans._matrix_(ZZ)
     except:
-       print "Hadamard matrix of order ",n," does not exist or is not implemented yet."
+        raise NotImplementedError, "Hadamard matrix of order %s does not exist or is not implemented yet."%n
 
 def bell_number(n):