--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/polyfuncs.py	Fri May 27 14:24:59 2011 +0530
@@ -0,0 +1,164 @@
+#!/usr/bin/python
+# Contains all the polynomial functions
+
+import pylab as pl
+
+def polsize(Q, degQ):
+    """ Determines dimensions of a polynomial matrix. """
+    rQ, cQ = pl.atleast_2d(Q).shape
+    cQ = cQ/float(degQ+1)
+    if abs(round(cQ)-cQ) > 1e-6:
+        print "Degree of input inconsistent with number of columns"
+        return
+    else:
+        cQ = int(round(cQ))
+    return rQ, cQ
+
+def polmul(A, degA, B, degB):
+    A = pl.atleast_2d(A)
+    B = pl.atleast_2d(B)
+    rA, cA = polsize(A, degA)
+    rB, cB = polsize(B, degB)
+    if cA != rB:
+        print "polmul: Inconsistent dimensions of input matrices"
+        return
+    degC = degA + degB
+    C = []
+    for k in range(0, degC+1):
+        mi = 0
+        if k-degB > mi:
+            mi = k-degB
+        ma = degA
+        if k < ma:
+            ma = k
+        Ck = pl.zeros((rA,cB))
+        for i in range(mi, ma+1):
+            Ck = Ck + pl.dot(A[..., i*cA:(i+1)*cA], B[..., (k-i)*cB:(k-i+1)*cB])
+        Ck = pl.squeeze(Ck)
+        C = pl.hstack((C, Ck))
+    return C, degC
+
+def poladd(A, degA, B, degB):
+    A = pl.atleast_2d(A)
+    B = pl.atleast_2d(B)
+    rA, cA = polsize(A, degA)
+    rB, cB = polsize(B, degB)
+    if cA != rB:
+        print "polmul: Inconsistent dimensions of input matrices"
+        return
+    degC = max(degA, degB)
+
+    if degC >= degA:
+        A = pl.hstack((A, pl.zeros((rA,(degC-degA)*cA))))
+
+    if degC >= degB:
+        B = pl.hstack((B, pl.zeros((rB,(degC-degB)*cB))))
+
+    C = A + B
+    return C, degC
+
+def polsplit2(fac, a=1-1e-5):
+    fac = pl.atleast_1d(fac)
+    if a>1:
+        print "good polynomial also is unstable"
+        return
+    roots = pl.roots(fac)
+
+    # extract good and bad roots
+    badindex = pl.find(pl.absolute(roots)>=a-1.0e-5)
+    badpoly = pl.poly(roots[badindex])
+    goodindex = pl.find(pl.absolute(roots)<a-1.0e-5)
+    goodpoly = pl.poly(roots[goodindex])
+    # scale by equating the largest terms
+    index = pl.absolute(fac).argmax()
+    goodbad = pl.convolve(goodpoly, badpoly)
+    factor = fac[index]/goodbad[index]
+    goodpoly = goodpoly * factor
+    badpoly = pl.atleast_1d(badpoly)
+    goodpoly = pl.atleast_1d(goodpoly)
+    return goodpoly, badpoly
+
+def polsplit3(fac, a=1):
+    fac = pl.atleast_1d(fac)
+    if a>1:
+        print "good polynomial also is unstable"
+        return
+    roots = pl.roots(fac)
+
+    # extract good and bad roots
+    badindex = pl.find((pl.absolute(roots)>=a-1.0e-5) + (pl.real(roots)<-0.05))
+    badpoly = pl.poly(roots[badindex])
+    goodindex = pl.find((pl.absolute(roots)<a-1.0e-5) * (pl.real(roots)>=-0.05))
+    goodpoly = pl.poly(roots[goodindex])
+    # scale by equating the largest terms
+    index = pl.absolute(fac).argmax()
+    goodbad = pl.convolve(goodpoly, badpoly)
+    factor = fac[index]/goodbad[index]
+    goodpoly = goodpoly * factor
+    badpoly = pl.atleast_1d(badpoly)
+    goodpoly = pl.atleast_1d(goodpoly)
+    return goodpoly, badpoly
+
+def putin(A, degA, B, degB, i, j):
+    from clcoef import clcoef
+    A = pl.atleast_2d(A)
+    B = pl.atleast_2d(B)
+    rA, cA = polsize(A,degA)
+    if degB > degA:
+        A = pl.hstack((A, pl.zeros((rA,(degB-degA)*cA))))
+    degA = degB
+
+    for k in range(degB+1):
+        A[i,(k*cA)+j] = B[0,k]
+
+    if degA > degB:
+        for k in range(degB+1,degA+1):
+            A[i,(k*cA)+j] = 0
+        A, degA = clcoef(A,degA)
+    return A, degA
+
+
+def ext(A, degA, k, l):
+    from clcoef import clcoef
+    rA, cA = polsize(A, degA)
+    degB = degA
+    B = pl.zeros((1, degB+1))
+    for m in range(degB+1):
+        B[0, m] = A[k, (m*cA)+l]
+    B,degB = clcoef(B, degB)
+    return B, degB
+
+
+def transp(Q, degQ):
+    """ Function to transpose a polynomial matrix. """
+    rQ, cQ = polsize(Q, degQ)
+    rP = cQ
+    cP = rQ
+    degP = degQ
+    P = pl.zeros((rP, (degP+1)*cP))
+    for i in range(degP+1):
+        P[:, i*cP:(i+1)*cP] = Q[:, i*cQ:(i+1)*cQ].T
+
+    return P, degP
+
+
+if __name__== "__main__":
+
+    # print "Test for polsize"
+    # print polsize([1, 2, 1],4)
+
+    # print "Test for polmul"
+    # C = pl.array([[1, 0, 0.5, 2], [0, 1, -4.71, 2.8]]) 
+    # A = pl.array([0.5, 3.5])
+    # print polmul(A, 0, C, 1)
+
+    # print "Test for polsplit3"
+    # print polsplit3([1, -0.37])
+
+    print "Test for putin"
+    A = pl.array([0,0])
+    B = pl.array([0.44, -1.6, 1.6, -0.44])
+    print putin(A, 0, B, 3, 0, 0)
+
+    
+    pass