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Here are some examples using synthetic data.
Create a synthetic data set:
datasynth -testfunc 3 -snr 16 -voxels 4 -schemefile test/bmx7.scheme > T3_BMX7.Bfloat
Fit the spherical harmonics with maximum order 2 and compute the anisotropy:
shfit -order 2 -schemefile test/bmx7.scheme < T3_BMX7.Bfloat | sfanis -inputmodel sh -order 2 | double2txt
2.588603E-01
2.597550E-01
2.537685E-01
2.980303E-01
Try with maximum order 4: shfit -order 4 -schemefile test/bmx7.scheme < T3_BMX7.Bfloat | sfanis -inputmodel sh -order 4 | double2txt
2.983556E-01
3.064308E-01
2.876707E-01
3.385700E-01
Repeat using PASMRI: mesd -filter PAS 1.4 -schemefile test/bmx7.scheme < T3_BMX7.Bfloat | sfanis -inputmodel maxent -filter PAS 1.4 -mepointset 54 | double2txt
9.936683E-01
9.938231E-01
9.579966E-01
9.970216E-01
Repeat using QBALL: qballmx -schemefile test/bmx7.scheme > /tmp/bmx7_QBALLMX.Bdouble linrecon T3_BMX7.Bfloat test/bmx7.scheme /tmp/bmx7_QBALLMX.Bdouble -normalize | sfanis -inputmodel rbf -rbfpointset 246 -rbfsigma 0.2617993877991494 -schemefile test/bmx7.scheme | double2txt 1.049307E-01 1.180261E-01 1.087973E-01 1.186283E-01
And spherical harmonic q-ball qballmx -schemefile test/bmx7.scheme -basistype sh -order 4 > /tmp/bmx7_QBALLMX.Bdouble linrecon T3_BMX7.Bfloat test/bmx7.scheme /tmp/bmx7_QBALLMX.Bdouble -normalize | sfanis -inputmodel sh -order 4 -schemefile test/bmx7.scheme | double2txt 1.204591E-01 1.364328E-01 1.265906E-01 1.379158E-01
sh - Spherical harmonic series. (Must specify -order.)
maxent - Maximum entropy representations output by mesd. (Must specify -filter and -mepointset.)
rbf - Sums of radial basis functions. (Must specify rbf parameters, eg -rbfsigma, and -rbfpointset.)
0 - 1082
1 - 1922
2 - 4322
3 - 8672
4 - 15872
5 - 32672
6 - 72032
7 - 78032
The default is point set 3.