public Axis ExtractAxis <T>(Tensor <T> t, int i)
{
if (IsSingleton)
{
return(null);
}
var axis = t.Shape[i];
if (Step.IsOne)
{
// [x:]
if (Stop == null || Stop.IsConst(int.MaxValue))
{
return(axis - GetAbsoluteIndex(t, i, Start));
}
}
else if (Step.Check((Int s) => s.Value < 0))
{
// [x::-s]
if (Stop.IsConst(int.MinValue))
{
// [::-s]
if (Start.IsMinusOne)
{
return(axis / -Step);
}
else
{
return((GetAbsoluteIndex(t, i, Start) + 1) / -Step);
}
}
}
var stop = GetAbsoluteIndex(t, i, Stop);
var start = GetAbsoluteIndex(t, i, Start);
return((stop - start) / Step);
}