Is it possible to create a dynamically changing map? For example, i want to use it in the for loop, and use i as a variable in map value:

uint8_t i{};

std::map<uint8_t, int16_t> substitutions{
  {0, array[i][0]},
  {1, array[i][1]}, 
  {2, array[i][2]}, 
  {3, array[i][0] * array[i][1]}, 
  {4, array[i][0] * array[i][2]}, 
  {5, array[i][1] * array[i][2]}, 
  {6, array[i][0] * array[i][1] * array[i][2]}, 
  {7, pow(array[i][0], 2)}, 
  {8, pow(array[i][1], 2)}, 
  {9, pow(array[i][2], 2)}};

for (i = 0; i < 3; i++)
{
  anmSum += substitutions.find(a)->second * substitutions.find(b)->second;
}

Right now it just substitutes 0 (because i = 0) and leaves it at that.
Maybe instead of fixed values use lambda-function?

>Solution :

I’d probably solve your problem by not using a map at all. I’d use a switch statement instead (it should be slightly faster):

for (uint8_t i = 0; i < 3; i++)
{
  auto substitute = [i](uint8_t value)
  {
    switch (value)
    {
    case 0: return array[i][0];
    case 1: return array[i][1];
    case 2: return array[i][2];
    case 3: return array[i][0] * array[i][1]};
    case 4: return array[i][0] * array[i][2]};
    case 5: return array[i][1] * array[i][2]};
    case 6: return array[i][0] * array[i][1] * array[i][2]};
    case 7: return pow(array[i][0], 2)};
    case 8: return pow(array[i][1], 2)};
    case 9: return pow(array[i][2], 2)};
    default: throw std::invalid_argument("invalid value");
    };
  };
  anmSum += substitute(a) * substitute(b);
}

Using your approach you’d have to make your map contain some sort of function pointer.