def calculate(self, parameters_dict):
"""Calculate DKI statistics like the mean, axial and radial kurtosis.
The Mean Kurtosis (MK) is calculated by averaging the Kurtosis over orientations on the unit sphere.
The Axial Kurtosis (AK) is obtained using the principal direction of diffusion (fe; first eigenvec)
from the Tensor as its direction and then averaging the Kurtosis over +fe and -fe.
Finally, the Radial Kurtosis (RK) is calculated by averaging the Kurtosis over a circle of directions around
the first eigenvec.
Args:
parameters_dict (dict): the fitted Kurtosis parameters, this requires a dictionary with at least
the elements:
'd', 'dperp0', 'dperp1', 'theta', 'phi', 'psi', 'W_0000', 'W_1000', 'W_1100', 'W_1110',
'W_1111', 'W_2000', 'W_2100', 'W_2110', 'W_2111', 'W_2200', 'W_2210', 'W_2211',
'W_2220', 'W_2221', 'W_2222'.
Returns:
dict: maps for the Mean Kurtosis (MK), Axial Kurtosis (AK) and Radial Kurtosis (RK).
"""
if parameters_dict['d'].dtype == np.float32:
np_dtype = np.float32
mot_float_type = SimpleCLDataType.from_string('float')
double_precision = False
else:
np_dtype = np.float64
mot_float_type = SimpleCLDataType.from_string('double')
double_precision = True
param_names = ['d', 'dperp0', 'dperp1', 'theta', 'phi', 'psi', 'W_0000', 'W_1000', 'W_1100', 'W_1110',
'W_1111', 'W_2000', 'W_2100', 'W_2110', 'W_2111', 'W_2200', 'W_2210', 'W_2211',
'W_2220', 'W_2221', 'W_2222']
parameters = np.require(np.column_stack([parameters_dict[n] for n in param_names]),
np_dtype, requirements=['C', 'A', 'O'])
directions = convert_data_to_dtype(self._get_spherical_samples(), 'mot_float_type4', mot_float_type)
return self._calculate(parameters, param_names, directions, double_precision)
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