r19851 - in /branches/relax_disp: lib/dispersion/equations.py specific_analyses/relax_disp/__init__.py -- June 03, 2013 - 19:53

Author: bugman
Date: Mon Jun  3 19:53:30 2013
New Revision: 19851

URL: http://svn.gna.org/viewcvs/relax?rev=19851&view=rev
Log:
Created the lib.dispersion.equations.calc_two_point_r2eff_err() function.

This complements the lib.dispersion.equations.calc_two_point_r2eff() function 
and is used by the
dispersion calculate() method to abstract the mathematics.


Modified:
    branches/relax_disp/lib/dispersion/equations.py
    branches/relax_disp/specific_analyses/relax_disp/__init__.py

Modified: branches/relax_disp/lib/dispersion/equations.py
URL: 
http://svn.gna.org/viewcvs/relax/branches/relax_disp/lib/dispersion/equations.py?rev=19851&r1=19850&r2=19851&view=diff
==============================================================================
--- branches/relax_disp/lib/dispersion/equations.py (original)
+++ branches/relax_disp/lib/dispersion/equations.py Mon Jun  3 19:53:30 2013
@@ -24,7 +24,7 @@
 """The relaxation dispersion equations."""
 
 # Python module imports.
-from math import log
+from math import log, sqrt
 
 
 def calc_two_point_r2eff(relax_time=None, I_ref=None, I=None):
@@ -49,3 +49,31 @@
 
     # Calculate and return the value (avoiding integer division problems).
     return -1.0 / relax_time * log(float(I) / I_ref)
+
+
+def calc_two_point_r2eff_err(relax_time=None, I_ref=None, I=None, 
I_ref_err=None, I_err=None):
+    """Calculate the R2eff/R1rho error for the fixed relaxation time data.
+
+    The formula is:
+
+                  -1         / I1 \ 
+        R2eff = ------- * ln | -- | ,
+                relax_T      \ I0 /
+
+    where relax_T is the fixed delay time, I0 is the reference peak 
intensity when relax_T is zero, and I1 is the peak intensity in a spectrum of 
interest.
+
+
+    @keyword relax_time:    The fixed relaxation delay time in seconds.
+    @type relax_time:       float
+    @keyword I_ref:         The peak intensity in the reference spectrum.
+    @type I_ref:            float
+    @keyword I:             The peak intensity of interest.
+    @type I:                float
+    @keyword I_ref_err:     The peak intensity error in the reference 
spectrum.
+    @type I_ref_err:        float
+    @keyword I_err:         The peak intensity error of interest.
+    @type I_err:            float
+    """
+
+    # Calculate and return the value (avoiding integer division problems).
+    return sqrt((ref_intensity_err / ref_intensity)**2 + (intensity_err / 
intensity)**2) / relax_time

Modified: branches/relax_disp/specific_analyses/relax_disp/__init__.py
URL: 
http://svn.gna.org/viewcvs/relax/branches/relax_disp/specific_analyses/relax_disp/__init__.py?rev=19851&r1=19850&r2=19851&view=diff
==============================================================================
--- branches/relax_disp/specific_analyses/relax_disp/__init__.py (original)
+++ branches/relax_disp/specific_analyses/relax_disp/__init__.py Mon Jun  3 
19:53:30 2013
@@ -33,7 +33,6 @@
 
 # Python module imports.
 from copy import deepcopy
-from math import sqrt 
 from minfx.generic import generic_minimise
 from minfx.grid import grid
 from numpy import array, average, dot, float64, identity, log, ones, zeros
@@ -973,8 +972,8 @@
                 # Calculate the R2eff value.
                 spin.r2eff[param_key] = 
calc_two_point_r2eff(relax_time=time, I_ref=ref_intensity, I=intensity)
 
-                # The R2eff error.
-                spin.r2eff_err[param_key] = sqrt((ref_intensity_err / 
ref_intensity)**2 + (intensity_err / intensity)**2) / time
+                # Calculate the R2eff error.
+                spin.r2eff_err[param_key] = 
calc_two_point_r2eff_err(relax_time=time, I_ref=ref_intensity, I=intensity, 
I_ref_err=ref_intensity_err, I_err=intensity_err)
 
 
     def constraint_algorithm(self):