  function transferNotionalFrom(address f, address t, uint256 a) external onlyAdmin(admin) returns (bool) {
  Vault memory from = vaults\[f];
  Vault memory to = vaults\[t];
  ...
  vaults\[f] = from;
  ...
  vaults\[t] = to;    // if f==t then this will overwrite vaults\[f]
  function transferVaultNotional(address u, uint256 m, address t, uint256 a) public returns (bool) {
  require(VaultTracker(markets\[u]\[m].vaultAddr).transferNotionalFrom(msg.sender, t, a), 'vault transfer failed');
