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dteig

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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>

BUGS

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Time: 02:07:11 GMT, December 04, 2017

Dteig