hello , i need help

[romeric]

hello , i need help

[XDongiang]

and the leci_four is

// definition of epsilon_{mu,nu}, the whole anti-symmetric tensor
Tensor<double, 4, 4, 4, 4> leci_four()
{
    Tensor<double, 4, 4, 4, 4> leci;
    leci.zeros();
    leci(0, 1, 2, 3) = 1.;
    leci(0, 1, 3, 2) = -1.;
    leci(0, 3, 1, 2) = 1.;
    leci(3, 0, 1, 2) = -1.;
    leci(3, 0, 2, 1) = 1.;
    leci(0, 3, 2, 1) = -1.;
    leci(0, 2, 3, 1) = 1.;
    leci(0, 2, 1, 3) = -1.;
    leci(2, 0, 1, 3) = 1.;
    leci(2, 0, 3, 1) = -1.;
    leci(2, 3, 0, 1) = 1.;
    leci(3, 2, 0, 1) = -1.;
    leci(3, 2, 1, 0) = 1.;
    leci(2, 3, 1, 0) = -1.;
    leci(2, 1, 3, 0) = 1.;
    leci(2, 1, 0, 3) = -1.;
    leci(1, 2, 0, 3) = 1.;
    leci(1, 2, 3, 0) = -1.;
    leci(1, 3, 2, 0) = 1.;
    leci(3, 1, 2, 0) = -1.;
    leci(3, 1, 0, 2) = 1.;
    leci(1, 3, 0, 2) = -1.;
    leci(1, 0, 3, 2) = 1.;
    leci(1, 0, 2, 3) = -1.;
    return leci;
}

i think it may have symmetry

[romeric]

What are the functions TT1 and TT2 and how does your main function that calls the function phif222 look like?

And what is the problem exactly? Does it not compile, or does it crash or do you get incorrect results?

[XDongiang]

sorry , my exactly question is : how to use einsum to calculate the function

how to determine the index order ? and

[XDongiang]

i have solve my problem . and i thank if can determin the index of output , it will more easy to use the einsum . now i must to control the order of input to control the index of output .