a := vf[i] / 10
		if f := Erfinv(a); !veryclose(erfinv[i], f) {
			t.Errorf("Erfinv(%g) = %g, want %g", a, f, erfinv[i])
		}
	}
	for i := 0; i < len(vferfinvSC); i++ {
		if f := Erfinv(vferfinvSC[i]); !alike(erfinvSC[i], f) {
			t.Errorf("Erfinv(%g) = %g, want %g", vferfinvSC[i], f, erfinvSC[i])
		}
	}
	for x := -0.9; x <= 0.90; x += 1e-2 {
		if f := Erf(Erfinv(x)); !close(x, f) {

  auto x = ConjugateHelper(grad_scope, op.input(0));
  // grad * sqrt(pi) / 2 * exp(erfinv(x) ** 2)
  auto dx = Mul(grad_scope, Mul(grad_scope, grad, root_pi_over_two),
                Exp(grad_scope, Square(grad_scope, op.output(0))));
  grad_outputs->push_back(dx);
  return grad_scope.status();
}
REGISTER_GRADIENT_OP("Erfinv", ErfinvGrad);

Status NdtriGrad(const Scope& scope, const Operation& op,

            "Log1p", "Invert", "LogicalNot", "Ndtri", "Neg", "Rint", "Round",
            "Rsqrt", "Sigmoid", "Sign", "Sinh", "Softplus", "Softsign", "Sqrt",
            "Square", "Tan", "Tanh", "Real", "Imag", "Erf", "Erfc", "Erfinv",
            "Lgamma", "Digamma",
            // Binary
            "Add", "AddV2", "Sub", "Mul", "Div", "Atan2", "Complex", "DivNoNan",
            "MulNoNan", "FloorDiv", "Xlogy", "Xlog1py", "Xdivy", "FloorMod",