A predicate.
Optimization: To check if any element was found use the last dimension (row index). This will slightly optimize the code.
if (backwardIndex) { auto elem1 = slice1.backward(backwardIndex); //... auto elemK = sliceK.backward(backwardIndex); } else { // not found }
Ranges and arrays
import std.range : iota; auto sl = iota(10); size_t index = sl.find!"a == 3"; assert(sl[$ - index] == 3);
import mir.ndslice.topology : iota; // 0 1 2 // 3 4 5 auto sl = iota(2, 3); size_t[2] bi = sl.find!"a == 3"; assert(sl.backward(bi) == 3); assert(sl[$ - bi[0], $ - bi[1]] == 3); bi = sl.find!"a == 6"; assert(bi[0] == 0); assert(bi[1] == 0);
Multiple slices
import mir.ndslice.topology : iota; // 0 1 2 // 3 4 5 auto a = iota(2, 3); // 10 11 12 // 13 14 15 auto b = iota([2, 3], 10); size_t[2] bi = find!((a, b) => a * b == 39)(a, b); assert(a.backward(bi) == 3); assert(b.backward(bi) == 13);
Zipped slices
import mir.ndslice.topology : iota, zip; // 0 1 2 // 3 4 5 auto a = iota(2, 3); // 10 11 12 // 13 14 15 auto b = iota([2, 3], 10); size_t[2] bi = zip!true(a, b).find!"a.a * a.b == 39"; assert(a.backward(bi) == 3); assert(b.backward(bi) == 13);
Mutation on-the-fly
import mir.ndslice.allocation : slice; import mir.ndslice.topology : as, iota; // 0 1 2 // 3 4 5 auto sl = iota(2, 3).as!double.slice; static bool pred(T)(ref T a) { if (a == 5) return true; a = 8; return false; } size_t[2] bi = sl.find!pred; assert(bi == [1, 1]); assert(sl.backward(bi) == 5); // sl was changed assert(sl == [[8, 8, 8], [8, 8, 5]]);
findIndex, any, mir.ndslice.slice.Slice.backward.
Optimization: find!"a" has accelerated specialization for slices created with mir.ndslice.topology.bitwise, mir.ndslice.allocation.bitSlice.
Finds a backward index such that pred(slices[0].backward(index), ..., slices[$-1].backward(index)) is true.