lookup method
Implementation
Tensor2D lookup(List<int> tokens) {
final T = tokens.length;
final out = Tensor2D.zeros(T, dim);
for (var i = 0; i < T; i++) {
final id = tokens[i];
if (id < 0 || id >= vocabSize) {
throw RangeError('token id out of range: $id');
}
final srcBase = id * dim;
final dstBase = i * dim;
for (var j = 0; j < dim; j++) {
out.data[dstBase + j] = weight.data[srcBase + j];
}
}
return out;
}