MS_axes.m with Browaeys and Chevrot (2004) example matrices

[carltape]

I am looking at the two example matrices in Browaeys and Chevrot (2004) [BC2004], for olivine (Section 4.1.1) and for enstatite (Section 4.1.2). I'll call these 6x6 Voigt matrices Colivine and Censtatite. The suggested approach in MSAT to the BC2004 decomposition is (see MSAT Walker paper, Listing 2): MS_axes, MS_decomp, MS_norms. I was expecting both of the BC2004 matrices to be in the SCCS (symmetry cartesian coordinate system) form (Section 3.2), which is supposedly achieved by using MS_axes.m. But when I run MS_axes(Colivine) and MS_axes(Censtatite), I get different matrices from the input ones. I'll refer to these as Colivine_MSaxes and Censtatite_MSaxes.

Running MS_decomp/MS_norms on Colivine and Colivine_MSaxes gives the same percentages as those listed in BC2004. Running MS_decomp/MS_norms on Censtatite gives the same percentages as those listed in the paper. Running MS_decomp/MS_norms on on Censtatite_MSaxes gives different percentages.

This may be more of a question for Browaeys and Chevrot, but I wanted to post the issue here, given that the BC decomposition is implemented in MSAT.

With Colivine and Censtatite devined, the Matlab code is

Colivine
Colivine_MSaxes = MS_axes(Colivine)
[Ciso,Chex,Ctet,Cort,Cmon,Ctri] = MS_decomp(Colivine);
Polivine = MS_norms(Colivine,Ciso,Chex,Ctet,Cort,Cmon,Ctri)
[Ciso,Chex,Ctet,Cort,Cmon,Ctri] = MS_decomp(Colivine_MSaxes);
Polivine_MSaxes = MS_norms(Colivine_MSaxes,Ciso,Chex,Ctet,Cort,Cmon,Ctri)

Censtatite
Censtatite_MSaxes = MS_axes(Censtatite)
[Ciso,Chex,Ctet,Cort,Cmon,Ctri] = MS_decomp(Censtatite);
Penstatite = MS_norms(Censtatite,Ciso,Chex,Ctet,Cort,Cmon,Ctri)
[Ciso,Chex,Ctet,Cort,Cmon,Ctri] = MS_decomp(Censtatite_MSaxes);
Penstatite_MSaxes = MS_norms(Censtatite_MSaxes,Ciso,Chex,Ctet,Cort,Cmon,Ctri)

The output is

Colivine =
   192    66    60     0     0     0
    66   160    56     0     0     0
    60    56   272     0     0     0
     0     0     0    60     0     0
     0     0     0     0    62     0
     0     0     0     0     0    49
Colivine_MSaxes =
   160    66    56     0     0     0
    66   192    60     0     0     0
    56    60   272     0     0     0
     0     0     0    62     0     0
     0     0     0     0    60     0
     0     0     0     0     0    49
Polivine =
    0.7930    0.1516    0.0034    0.0520         0         0
Polivine_MSaxes =
    0.7930    0.1516    0.0034    0.0520         0         0
Censtatite =
   225    54    72     0     0     0
    54   214    53     0     0     0
    72    53   178     0     0     0
     0     0     0    78     0     0
     0     0     0     0    82     0
     0     0     0     0     0    76
Censtatite_MSaxes =
   178    53    72     0     0     0
    53   214    54     0     0     0
    72    54   225     0     0     0
     0     0     0    76     0     0
     0     0     0     0    82     0
     0     0     0     0     0    78
Penstatite =
    0.9081    0.0426    0.0043    0.0450         0         0
Penstatite_MSaxes =
    0.9081    0.0210    0.0027    0.0682         0         0
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