Momentum tensor eigenvalues and eigenvectors

See also QJSPHE in 10.6 for sphericity value and axis.

Input argument:

ICLASS

described in 10.3.

Results:

EIGVAL

eigenvalues in descending order with DIMENSION EIGVAL(3).

• Sphericity = 1.5 * (1. - EIGVAL(1))
• Aplanarity = 1.5 * EIGVAL(3)
• Planarity = EIGVAL(2) - EIGVAL(3)
'eigenvector'
Three eigenvectors:
• IMAJOR = KPDIR ('eigenvector', ICLASS)
• ISEMI = KFOLLO (IMAJOR)
• IMINOR = KFOLLO (ISEMI)