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Program Invar_space


Invar_space 'file' [-a] [-s] [-e=n] [-d=n]
file: bravais_TYP containing a finite unimodular group G.


Calculates a Z-basis for the space of matrices with gtrAg = A for all g in G by a quick seminumerical algorithm with some random features. By default all symmetric invariant matrices are calculated.


-a:      All invariant matrices are calculated.
-s:      All skew-symmetric invariant matrices are calculated.
-e=n:    Changes the default value of control parameter from 100 to n>100.
-d=n:    The program will calculate n+1 elements F_0,..., F_n of the
         invariant space, then it calculates a Z-basis of the Q-span of
         F_0, ..., F_n intersected with Z^nxn.
         This option is only usefull if one knows the dimension of the
         space of invariant forms. By default this number is calculated
         by modular arithmetic.


See also for Form_space.


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