eigenvalue of big A matrix vs max magnitude

abstable.py

 from matplotlib import pyplot as plt
-from numpy import arange, zeros, linspace, sign
+from numpy import arange, zeros, linspace, sign, logspace, log10
 
 from idmlin import IDMLin
 
 
 t = 1.5
-amin, amax, acount = 0.1, 0.6, 50
-bmin, bmax, bcount = 2, 4, 100
+amin, amax, acount = log10(0.3), log10(3), 20
+bmin, bmax, bcount = log10(1), log10(4), 20
 
-arng = linspace(amin, amax, acount)
-brng = linspace(bmin, bmax, bcount)
+arng = logspace(amin, amax, acount)
+brng = logspace(bmin, bmax, bcount)
 s0 = 2
 v0 = 30
-re = 0.5
+re = 0.1
 
-ns = (10, 25, 50)
+ns = (200,)
 
 f, axarr = plt.subplots(2, len(ns)+1, sharex=True, sharey=True)
 #f, axarr = plt.subplots(2, 2, sharex=True, sharey=True)
@@ -29,10 +29,13 @@ for i, n in enumerate(ns):
     def isstable(a, b):
             idm = IDMLin(t=t, a=a, b=b, s0=s0)
             idm.go(v0, re)
-            if idm.isloopstable(n):
-                return 1, sign(idm.os())
-            else:
-                return 0, sign(idm.os())
+            sys = idm.sys()
+            ils = idm.isloopstable(n)
+            imr = idm.maxresponse()
+            print a, b, ils, imr
+
+            return 1 if ils else 0, imr
+            #return 1 if ils else 0, 1 if imr<0 else 0
 
     for ai, a in enumerate(arng):
         for bi, b in enumerate(brng):