r20273 - /branches/relax_disp/lib/dispersion/ns_2site_star.py -- July 11, 2013 - 16:08

Author: bugman
Date: Thu Jul 11 16:08:11 2013
New Revision: 20273

URL: http://svn.gna.org/viewcvs/relax?rev=20273&view=rev
Log:
Significant speed ups of the 
lib.dispersion.ns_2site_star.r2eff_ns_2site_star() function.

Replicated calculations have been minimised.


Modified:
    branches/relax_disp/lib/dispersion/ns_2site_star.py

Modified: branches/relax_disp/lib/dispersion/ns_2site_star.py
URL: 
http://svn.gna.org/viewcvs/relax/branches/relax_disp/lib/dispersion/ns_2site_star.py?rev=20273&r1=20272&r2=20273&view=diff
==============================================================================
--- branches/relax_disp/lib/dispersion/ns_2site_star.py (original)
+++ branches/relax_disp/lib/dispersion/ns_2site_star.py Thu Jul 11 16:08:11 
2013
@@ -69,21 +69,27 @@
     Rex = -1.0 * matrix([[kge, -keg],[-kge, keg]])
     RCS = complex(0.0, -1.0) * matrix([[0.0, 0.0],[0.0, fg]])
     R = Rr + Rex + RCS
-    cR = conj(R)
+    cR2 = conj(R) * 2.0
 
     kex = kge + keg
     IGeq = keg / kex
     IEeq = kge / kex
     M0 = matrix([[IGeq], [IEeq]])
 
+    # Replicated calculations for faster operation.
+    inv_tcpmg = 1.0 / tcpmg
+
     # Loop over the time points, back calculating the R2eff values.
     for i in range(num_points):
-        tcp = 1.0 / (4.0 * cpmg_frqs[i])
-        prop_2 = dot(dot(expm(R*tcp), expm(cR*2.0*tcp)), expm(R*tcp))
+        # Replicated calculations for faster operation.
+        tcp = 0.25 / cpmg_frqs[i]
+        expm_R_tcp = expm(R*tcp)
+
+        prop_2 = dot(dot(expm_R_tcp, expm(cR2*tcp)), expm_R_tcp)
 
         prop_total = mpower(prop_2, cpmg_frqs[i]*tcpmg)
 
         Moft = prop_total * M0
 
         Mgx = Moft[0].real / M0[0]
-        back_calc[i]= -(1.0/tcpmg) * log(Mgx)
+        back_calc[i]= -inv_tcpmg * log(Mgx)