From 971949fcb49cd302f588e9fee3a4f5825ef370cf Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <mathem@tiker.net>
Date: Wed, 15 Jun 2005 22:26:23 +0000
Subject: [PATCH] [pymbolic @
 Arch-1:inform@tiker.net--iam-2005%pymbolic--mainline--1.0--patch-9] Arch
 Inventory in mapper/ subdir.

---
 src/polynomial.py | 63 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 src/polynomial.py

diff --git a/src/polynomial.py b/src/polynomial.py
new file mode 100644
index 0000000..d455059
--- /dev/null
+++ b/src/polynomial.py
@@ -0,0 +1,63 @@
+class Polynomial(Expression):
+    def __init__(self, base, coeff):
+        self.Base = base
+
+        # list of (exponent, coefficient tuples)
+        # sorted in increasing order
+        # one entry per degree
+        self.Data = children 
+        
+        # Remember the Zen, Luke: Sparse is better than dense.
+
+    def __neg__(self):
+        return Polynomial(self.Base,
+                          [(exp, -coeff)
+                           for (exp, coeff) in self.Data])
+
+    def __add__(self, other):
+        if not isinstance(other, Polynomial) or other.Base != self.Base:
+            return Expression.__add__(self, other)
+
+        iself = 0
+        iother = 0
+
+        result = []
+        while iself < len(self.Data) and iother < len(other.Data):
+            exp_self = self.Data[iself][0]
+            exp_other = other.Data[iother][0]
+            if exp_self == exp_other:
+                coeff = self.Data[iself][1] + other.Data[iother][1]
+                if coeff != Constant(0):
+                    result.append((exp_self, coeff))
+                iself += 1
+                iother += 1
+            elif exp_self > exp_other:
+                result.append((exp_other, other.Data[iother][1]))
+                iother += 1
+            elif exp_self < exp_other:
+                result.append((exp_self, self.Data[iself][1]))
+                iself += 1
+
+        # we have exhausted at least one list, exhaust the other
+        while iself < len(self.Data):
+            exp_self = self.Data[iself][0]
+            result.append((exp_self, self.Data[iself][1]))
+            iself += 1
+                
+        while iother < len(other.Data):
+            exp_other = other.Data[iother][0]
+            result.append((exp_other, other.Data[iother][1]))
+            iother += 1
+
+        return Polynomial(self.Base, result)
+
+    def __mul__(self, other):
+        if not isinstance(other, Polynomial) or other.Base != self.Base:
+            return Expression.__mul__(self, other)
+        raise NotImplementedError
+
+    def __hash__(self):
+        return hash(self.Base) ^ hash(self.Children)
+
+    def invoke_mapper(self, mapper):
+        return mapper.map_polynomial(self)
-- 
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