--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lqg/lqg_simple.py	Fri May 27 14:24:59 2011 +0530
@@ -0,0 +1,34 @@
+#!/usr/bin/python
+# 13.4
+
+import os, sys
+sys.path += [os.getcwdu() + os.sep + ".." + os.sep + "python"]
+
+import scipy as sp
+from polyfuncs import polmul, putin, ext
+from xdync import xdync
+from zpowk import zpowk
+from specfac import specfac
+
+def lqg_simple(A,dA,B,dB,C,dC,k,rho,V,dV,W,dW,F,dF): 
+    """ LQG controller design by method of Ahlen and Sternad. """
+    r, b, db = specfac(A,dA,B,dB,rho,V,dV,W,dW,F,dF)
+    D, dD = polmul(A, dA, F, dF)
+    zk, dzk = zpowk(k)
+    N, dN = polmul(zk, dzk, B, dB)
+    RHS, dRHS = polmul(C, dC, b, db)
+    S, dS, R1, dR1 = xdync(N, dN, D, dD, RHS, dRHS)[:4]
+    return R1, dR1, S, dS
+
+if __name__ == "__main__":
+    A, dA = sp.array([1, -0.44]), 1
+    B, dB = sp.array([0.51, 1.21]), 1
+    F, dF = sp.array([1, -1]), 1
+    C, dC = sp.array([1, -0.44]),1
+    k = 1
+    V, W = 1, 1
+    dV, dW = 0, 0
+    rho = 1
+    int1 = 1
+
+    print lqg_simple(A,dA,B,dB,C,dC,k,rho,V,dV,W,dW,F,dF)