Function sprs::is_symmetric

pub fn is_symmetric<N, I, IpStorage, IStorage, DStorage>(
    mat: &CsMatBase<N, I, IpStorage, IStorage, DStorage>
) -> bool where
    N: Copy + PartialEq,
    I: SpIndex,
    IpStorage: Deref<Target = [I]>,
    IStorage: Deref<Target = [I]>,
    DStorage: Deref<Target = [N]>,