SymmetrizedReplacePart

SymmetrizedReplacePart[sa,{pos1->val1,pos2->val2,…}] replaces independent values of the symmetrized array sa as given by the rules posi->vali.

Examples

Replace a value in a symmetric array:

sa = SymmetrizedArray[{{1, 2} -> a, {2, 1} -> a}, {2, 2}, Symmetric[{1, 2}]];
SymmetrizedReplacePart[sa, {{1, 2} -> b}]

Modify an antisymmetric array:

asa = SymmetrizedArray[{{1, 2} -> x}, {3, 3}, Antisymmetric[{1, 2}]];
SymmetrizedReplacePart[asa, {{1, 3} -> y}]

Please visit the official Wolfram Language Reference for more details.