With[{get = Compile`GetElement},
basisCoeff[deg_, U_, i_, u_] :=
If[U[[i + deg + 1]] !=
U[[i + 1]], (u - get[U, i + 1])/(get[U, i + deg + 1] -
get[U, i + 1]), 0.];
optimizedNonzeroBasis2 =
ReleaseHold[
Hold@Compile[{{deg, _Integer}, {knots, _Real,
1}, {u0, _Real}, {i, _Integer}},
Module[{lst = Table[0., {deg + 2}, {deg + 1}], c = i - 2},
lst[[2, 1]] = 1.0;
Do[
With[{mn = m + n},
lst[[mn - c, n + 1]] =
basisCoeff[n, knots, m, u0] get[lst, mn - c - 1,
n] + (1 - basisCoeff[n, knots, m + 1, u0]) get[lst,

fullycompiledBSplineSurf2 =
Hold@Compile[{{ctrlnets, _Real,
3}, {deg1, _Integer}, {deg2, _Integer}, {knots1, _Real,
1}, {knots2, _Real, 1}, {u, _Real}, {v, _Real}},
Module[{i, j, validnets, row, col},
i = With[{un = #2[[-(#1 + 1)]]},
If[#3 == un,
Position[#2, un][[1, 1]] -
2, (Position[#, Min[#]] &@UnitStep[#3 - #2])[[1, 1]] -
2]] &[deg1, knots1, u];
j =
With[{un = #2[[-(#1 + 1)]]},
If[#3 == un,
Position[#2, un][[1, 1]] -
2, (Position[#, Min[#]] &@UnitStep[#3 - #2])[[1, 1]] -
2]] &[deg2, knots2, v];