X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo%2Feja%2Feja_utils.py;h=a4328610e5e41db689455828bd0d8988225e745b;hb=e8599960ef47e5a5af8aca360a041d30584f6c3f;hp=6f8cab6d8019dcbba0be1e81c3872a7ba738f807;hpb=a46720db62543983ab375654dee211ca844ac46c;p=sage.d.git

diff --git a/mjo/eja/eja_utils.py b/mjo/eja/eja_utils.py
index 6f8cab6..a432861 100644
--- a/mjo/eja/eja_utils.py
+++ b/mjo/eja/eja_utils.py
@@ -1,7 +1,44 @@
 from sage.functions.other import sqrt
+from sage.structure.element import is_Matrix
 from sage.matrix.constructor import matrix
 from sage.modules.free_module_element import vector
 
+def _charpoly_sage_input(s):
+    r"""
+    Helper function that you can use on the string output from sage
+    to convert a charpoly coefficient into the corresponding input
+    to be cached.
+
+    SETUP::
+
+        sage: from mjo.eja.eja_algebra import JordanSpinEJA
+        sage: from mjo.eja.eja_utils import _charpoly_sage_input
+
+    EXAMPLES::
+
+        sage: J = JordanSpinEJA(4,QQ)
+        sage: a = J._charpoly_coefficients()
+        sage: a[0]
+        X1^2 - X2^2 - X3^2 - X4^2
+        sage: _charpoly_sage_input(str(a[0]))
+        'X[0]**2 - X[1]**2 - X[2]**2 - X[3]**2'
+
+    """
+    import re
+
+    exponent_out = r"\^"
+    exponent_in = r"**"
+
+    digit_out = r"X([0-9]+)"
+
+    def replace_digit(m):
+        # m is a match object
+        return "X[" + str(int(m.group(1)) - 1) + "]"
+
+    s = re.sub(exponent_out, exponent_in, s)
+    return re.sub(digit_out, replace_digit, s)
+
+
 def _scale(x, alpha):
     r"""
     Scale the vector, matrix, or cartesian-product-of-those-things
@@ -106,21 +143,21 @@ def _all2list(x):
         [3, 4, 1, 0, 0, 0, 0, 0, 0, 0]
 
     """
-    if hasattr(x, 'list') and hasattr(x, 'to_vector'):
-        # This avoids calling to_vector() on a matrix algebra with
-        # e.g. quaternions where the returned vector is of the wrong
-        # length (three instead of four) because the quaternions don't
-        # know how many generators they have.
-        return _all2list(x.list())
-
     if hasattr(x, 'to_vector'):
         # This works on matrices of e.g. octonions directly, without
         # first needing to convert them to a list of octonions and
         # then recursing down into the list. It also avoids the wonky
         # list(x) when x is an element of a CFM. I don't know what it
-        # returns but it aint the coordinates. This will fall through
-        # to the iterable case the next time around.
-        return _all2list(x.to_vector())
+        # returns but it aint the coordinates. We don't recurse
+        # because vectors can only contain ring elements as entries.
+        return x.to_vector().list()
+
+    if is_Matrix(x):
+        # This sucks, but for performance reasons we don't want to
+        # call _all2list recursively on the contents of a matrix
+        # when we don't have to (they only contain ring elements
+        # as entries)
+        return x.list()
 
     try:
         xl = list(x)
@@ -131,7 +168,7 @@ def _all2list(x):
         # Avoid the retardation of list(QQ(1)) == [1].
         return [x]
 
-    return sum(list( map(_all2list, xl) ), [])
+    return sum( map(_all2list, xl) , [])