VecF64.generate constructor
Implementation
factory VecF64.generate(int length, double Function(int i) generator) {
  final p = ccore.std_VecF64_new(length);
  for (var i = 0; i < length; i++) {
    ccore.std_VecF64_set(p, i, generator(i));
  }
  return VecF64.fromPointer(p, length: length);
}