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Manpage of dteig
dteig
Section: User Commands (1)
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NAME
dteig - Computes the eigensystem of tensors.
SYNOPSIS
dteig -inputmodel <dt (default) | multitensor>
DESCRIPTION
Reads diffusion tensor (single, two-tensor, three-tensor or
multitensor) data from the standard input, computes the eigenvalues
and eigenvectors of each tensor and outputs the results to the
standard output. For multiple-tensor data the program outputs the
eigensystem of each tensor. For each tensor the program outputs:
{l_1, e_11, e_12, e_13, l_2, e_21, e_22, e_33, l_3, e_31, e_32, e_33},
where l_1 >= l_2 >= l_3 and e_i = (e_i1, e_i2, e_i3) is the
eigenvector with eigenvalue l_i. For three-tensor data, for example,
the output contains thirty-six values per voxel.
EXAMPLES
Compute the eigensystem in each voxel of diffusion MRI data set
SubjectA.Bfloat and store the output in EigenA.Bdouble:
dtfit SubjectA.Bfloat test/A.scheme | dteig > EigenA.Bdouble
Compute the eigensystem for each component of the two-tensor fit to
the same data set:
twotenfit SubjectA.Bfloat test/A.scheme | dteig -inputmodel
multitensor > EigenA.Bdouble
Compute the eigensystem for 10000 independent trials of fitting the
diffusion tensor to data synthesized from test function 1 (see
datasynth(1)) using imaging scheme A.scheme and assuming signal to
noise ratio of 16 at b=0:
datasynth -testfunc 1 -voxels 10000 -snr 16 -schemefile A.scheme | dtfit - A.scheme | dteig > EigenA_SNR16.Bdouble
OPTIONS
- -inputmodel <model type>
-
Specifies the model that the input data contains parameters for.
Possible model types are: "dt" (diffusion-tensor data) and "multitensor" (see multitenfit(1)).
By default, the program assumes that the input data contains a single diffusion tensor
in each voxel. If the input model is "multitensor", the program
assumes a maximum of two tensors per voxel unless told otherwise with
the -maxcomponents option.
- -maxcomponents <number>
-
The maximum number of tensor components in a voxel of the input data.
- -inputdatatype <data type of input>
-
Specifies the data type of the input file. The data type can be any
of the following strings: "char", "short", "int", "long", "float" or
"double". See camino(1).
- -outputdatatype <data type of output>
-
Specifies the data type of the output data. The data type can be any
of the following strings: "char", "short", "int", "long", "float" or
"double". See camino(1).
AUTHORS
Daniel Alexander <camino@cs.ucl.ac.uk>
SEE ALSO
fa(1), trd(1), dtfit(1), twotenfit(1), threetenfit(1), modelfit(1).
BUGS
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- EXAMPLES
-
- OPTIONS
-
- AUTHORS
-
- SEE ALSO
-
- BUGS
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