If you remove "signed" from your question this is equivalent to the isomorphism problem of vertex and edge labeled directed graphs. To do that in Sage let us define the following auxilliary function that turns a matrix into a (edge labeled) directed graph

```
def mat_to_dig(A):
n = A.nrows()
G = DiGraph(loops=False, multiedges=False)
for i in range(n):
for j in range(n):
if A[i,j]:
G.add_edge(i, j, A[i,j])
return G
```

Now, (assuming that I care about matrix with 0 on the diagonal)

```
sage: A = matrix(4, [0,1,2,3,4,0,5,6,7,8,0,9,10,11,12,0])
sage: A
[ 0 1 2 3]
[ 4 0 5 6]
[ 7 8 0 9]
[10 11 12 0]
sage: p = Permutation('(1,3)(2,4)')
sage: B = copy(A)
sage: B.permute_rows_and_columns(p,p)
sage: B
[ 0 9 7 8]
[12 0 10 11]
[ 2 3 0 1]
[ 5 6 4 0]
sage: G = mat_to_dig(A)
sage: H = mat_to_dig(B)
sage: G.is_isomorphic(H, edge_labels=True, certificate=True)
(True, {0: 2, 1: 3, 2: 0, 3: 1})
```

The dictionary `{0: 2, 1: 3, 2: 0, 3: 1}`

gives you the permutation to be performed namely `0↦2, 1↦3, 2↦0, 3↦1`

.

Now, if you want to consider the signed version what you can do is to replace your graph by a "signed graph" in which the vertices are doubled.

```
def mat_to_signed_dig(A):
n = A.nrows()
G = DiGraph(loops=False, multiedges=False)
for i in range(n):
for j in range(n):
if A[i,j]:
G.add_edge(i, j, A[i,j])
G.add_edge(n+i, n+j, A[i,j])
G.add_edge(i, n+j, -A[i,j])
G.add_edge(n+i, j, -A[i,j])
return G
```

Then

```
sage: A = matrix(4, [0,1,2,3,4,0,5,6,7,8,0,9,10,11,12,0])
sage: p = matrix(Permutation('(1,3)(2,4)')) * diagonal_matrix([1,-1,-1,1])
sage: B = p * A * ~p
sage: B
[ 0 -9 -7 8]
[-12 0 10 -11]
[ -2 3 0 -1]
[ 5 -6 -4 0]
sage: G = mat_to_signed_dig(A)
sage: H = mat_to_signed_dig(B)
sage: G.is_isomorphic(H, edge_labels=True, certificate=True)
(True, {0: 6, 1: 3, 2: 0, 3: 5, 4: 2, 5: 7, 6: 4, 7: 1})
```

The dictionary now corresponds to a signed permutation where `i+4`

should be thought as `-i`

. So it should be interpreted as the signed permutation `+0↦-2, +1↦+3, +2↦+0, +3↦-1, -0↦+2, -1↦-3, -2↦-0, -3->+1`

.

What are the entries of the matrices? Real numbers or integers or?

The nature of the entries should not matter. For the problem to make sense you only need to be able to test for equality of entries and negates an entry.

the matrices are symmetric seidl matrices of simple graphs. zero on the diagonal , 1 and -1 off the diagonal

let A and B the seidel adjacency matrices of two simple graphs. How to write a code in sageMath for find a signed permutation matrix which gives A and B are similar