eja: fix complex-unembedding with respect to 5537f4534.

[sage.d.git] / mjo / eja / euclidean_jordan_algebra.py

diff --git a/mjo/eja/euclidean_jordan_algebra.py b/mjo/eja/euclidean_jordan_algebra.py
index 3cec4fad035e0330e22598bd77f6e5b1dc9b6074..1e5ada2188c3b6b3834165f221ab20b56d5c1f98 100644 (file)
--- a/mjo/eja/euclidean_jordan_algebra.py
+++ b/mjo/eja/euclidean_jordan_algebra.py
@@ -1182,13 +1182,13 @@ def _embed_complex_matrix(M):
         sage: x2 = F(1 + 2*i)
         sage: x3 = F(-i)
         sage: x4 = F(6)
-        sage: M = matrix(F,2,[x1,x2,x3,x4])
+        sage: M = matrix(F,2,[[x1,x2],[x3,x4]])
         sage: _embed_complex_matrix(M)
-        [ 4  2| 1 -2]
-        [-2  4| 2  1]
+        [ 4 -2| 1  2]
+        [ 2  4|-2  1]
         [-----+-----]
-        [ 0  1| 6  0]
-        [-1  0| 0  6]
+        [ 0 -1| 6  0]
+        [ 1  0| 0  6]
 
     """
     n = M.nrows()
@@ -1199,7 +1199,7 @@ def _embed_complex_matrix(M):
     for z in M.list():
         a = z.real()
         b = z.imag()
-        blocks.append(matrix(field, 2, [[a,-b],[b,a]]))
+        blocks.append(matrix(field, 2, [[a,b],[-b,a]]))
 
     # We can drop the imaginaries here.
     return block_matrix(field.base_ring(), n, blocks)
@@ -1216,8 +1216,17 @@ def _unembed_complex_matrix(M):
         ....:                 [ 9,  10, 11, 12],
         ....:                 [-10, 9, -12, 11] ])
         sage: _unembed_complex_matrix(A)
-        [  -2*i + 1   -4*i + 3]
-        [ -10*i + 9 -12*i + 11]
+        [  2*i + 1   4*i + 3]
+        [ 10*i + 9 12*i + 11]
+
+    TESTS::
+
+        sage: set_random_seed()
+        sage: F = QuadraticField(-1, 'i')
+        sage: M = random_matrix(F, 3)
+        sage: _unembed_complex_matrix(_embed_complex_matrix(M)) == M
+        True
+
     """
     n = ZZ(M.nrows())
     if M.ncols() != n:
@@ -1238,7 +1247,7 @@ def _unembed_complex_matrix(M):
                 raise ValueError('bad real submatrix')
             if submat[0,1] != -submat[1,0]:
                 raise ValueError('bad imag submatrix')
-            z = submat[0,0] + submat[1,0]*i
+            z = submat[0,0] + submat[0,1]*i
             elements.append(z)
 
     return matrix(F, n/2, elements)