Hey Dan,
I only meant if you use the same alpha for all paths, you're assuming an isotropic expansion. Different alphas is one way to get rid of that.
One other thing I noticed-- in your first message, it says the r-range you used in the fit is the default-- 1 Hi Shelly, I seperated the delr's with different alpha terms, but Mike seems to think
that this is assuming isotropic expansion that isn't there. Also, the reduced
chi-square has gone up 150 or so. delr# define: alpha# * reff Thanks for the help, Dan Results with 1 eO and differing delr's: Independent points = 14.312500000
Number of variables = 7.000000000
Chi-square = 6186.771083042
Reduced Chi-square = 846.054165202
R-factor = 0.031090393
Measurement uncertainty (k) = 0.000181935
Measurement uncertainty (R) = 0.004860095
Number of data sets = 1.000000000 Guess parameters +/- uncertainties (initial guess):
ss = 0.0042720 +/- 0.0006590 (guessed as 0.004636
(0.000411))
e0 = 1.3293700 +/- 1.4673640 (guessed as 1.765958
(1.154388))
alpha = -0.0001750 +/- 0.0040010 (guessed as 0.001090
(0.002843))
ss2 = 0.0043180 +/- 0.0007370 (0.0000)
ss3 = 0.0072300 +/- 0.0164390 (0.0000)
alpha2 = 0.0076940 +/- 0.0027880 (0.0000)
alpha3 = -0.0512670 +/- 0.0232140 (0.0000) Def parameters:
delr_1 = -0.0006930
delr_2 = 0.0305320
delr_3 = -0.2034430 Set parameters:
amp = 0.7 Correlations between variables:
e0 and alpha --> 0.8441
ss3 and alpha2 --> 0.7651
ss2 and alpha2 --> -0.6441
e0 and alpha2 --> 0.5682
ss2 and ss3 --> 0.4871
alpha and alpha2 --> 0.4785
ss3 and alpha3 --> 0.3825
e0 and alpha3 --> -0.2743
All other correlations are below 0.25 Original (2 e0s): Independent points = 14.312500000
Number of variables = 6.000000000
Chi-square = 5778.957783654
Reduced Chi-square = 695.212966455
R-factor = 0.029041008
Measurement uncertainty (k) = 0.000181935
Measurement uncertainty (R) = 0.004860095
Number of data sets = 1.000000000 Guess parameters +/- uncertainties (initial guess):
e0_1 = -4.0347670 +/- 2.9998980 (guessed as -4.072009
(1.919404))
ss = 0.0042860 +/- 0.0005990 (guessed as 0.004636
(0.000411))
e0 = 1.6770760 +/- 1.3230290 (guessed as 1.765958
(1.154388))
alpha = 0.0009180 +/- 0.0034050 (guessed as 0.001090
(0.002843))
ss2 = 0.0048160 +/- 0.0006910 (0.0000)
ss3 = 0.0225310 +/- 0.0657250 (0.0000) Def parameters:
delr_1 = 0.0036440 Set parameters:
amp = 0.7 Correlations between variables:
e0_1 and alpha --> 0.8542
e0 and alpha --> 0.8470
e0_1 and e0 --> 0.7407
e0_1 and ss3 --> 0.7060
alpha and ss3 --> 0.4715
ss2 and ss3 --> -0.4214
e0_1 and ss2 --> -0.3892
e0 and ss3 --> 0.3772
alpha and ss2 --> -0.2680
All other correlations are below 0.25 _______________________________________________
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