--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/colsplit.py	Fri May 27 14:24:59 2011 +0530
@@ -0,0 +1,40 @@
+#!/usr/bin/python
+# Produces two polynomial matrices P1, P2
+# P1 consists of first p1 columns of P
+# P2 consists of remaining p2 columns of P
+
+import pylab as pl
+from polyfuncs import polsize
+
+def colsplit(P, degP, p1, p2):
+    P = pl.atleast_2d(P)
+    if pl.atleast_2d(P).size is 0:
+        P1 = pl.atleast_2d([])
+        P2 = pl.atleast_2d([])
+        return P1, None, P2, None
+
+    rP, cP = polsize(P, degP)
+
+    if not 0 <= p1 <= cP or not 0 <= p2 <= cP or p1+p2 != cP:
+        print 'colsplit: Inconsistent numbers of columns'
+        return None
+        exit(1)
+    
+    P1 = pl.atleast_2d(pl.zeros((rP, (degP+1)*p1)))
+    P2 = pl.atleast_2d(pl.zeros((rP, (degP+1)*p2)))
+    
+    
+    for i in range(degP+1):
+        P1[:,i*p1:(i+1)*p1] = P[:,i*cP:i*cP+p1]
+        P2[:,i*p2:(i+1)*p2] = P[:,i*cP+p1:(i+1)*cP]
+    
+    return P1, degP, P2, degP
+
+if __name__== "__main__":
+    s = """P = pl.array([[1, 2, 3, 4, 1, 2, 3, 4],
+           [9, 10, 11, 12, 9, 10, 11, 12],
+           [5, 6, 7, 8, 5, 6, 7, 8]])"""
+    print s
+    exec(s)
+    print """colsplit(P, 3, 1, 1)"""
+    print colsplit(P, 3, 1, 1)