}
		if err != nil {
			t.Errorf("scan%+v\n\tgot error = %s", a, err)
		}
	}
}

var natScanTests = []struct {
	s     string // string to be scanned
	base  int    // input base
	frac  bool   // fraction ok
	x     nat    // expected nat
	b     int    // expected base
	count int    // expected digit count
	err   error  // expected error
	next  rune   // next character (or 0, if at EOF)
}{

    // abs(sin(pi * frac(x))), where frac(x) is the fractional part of x.  This
    // is more numerically accurate: It doesn't overflow to inf like pi * x can,
    // and if x is an integer, it evaluates to 0 exactly, which is significant
    // because we then take the log of this value, and log(0) is inf.
    //
    // We don't have a frac(x) primitive in XLA and computing it is tricky, but

		{"0.5", 11, "1024"},
		{"-0.5", -2, "-0.125"},
		{"32", 5, "1024"},
		{"1024", -10, "1"},
	} {
		frac := makeFloat(test.frac)
		want := makeFloat(test.z)
		var z Float
		z.SetMantExp(frac, test.exp)
		if !alike(&z, want) {
			t.Errorf("SetMantExp(%s, %d) = %s; want %s", test.frac, test.exp, z.Text('g', 10), test.z)
		}
		// test inverse property
		mant := new(Float)

 * (unless there are {@link Double#NaN NaN} values, see below); otherwise, the result is the average
 * of the values which would appear at the indexes floor(x) and ceil(x) weighted by (1-frac(x)) and
 * frac(x) respectively. This is the same definition as used by Excel and by S, it is the Type 7
 * definition in <a
 * href="http://stat.ethz.ch/R-manual/R-devel/library/stats/html/quantile.html">R</a>, and it is
 * described by <a

 * (unless there are {@link Double#NaN NaN} values, see below); otherwise, the result is the average
 * of the values which would appear at the indexes floor(x) and ceil(x) weighted by (1-frac(x)) and
 * frac(x) respectively. This is the same definition as used by Excel and by S, it is the Type 7
 * definition in <a
 * href="http://stat.ethz.ch/R-manual/R-devel/library/stats/html/quantile.html">R</a>, and it is
 * described by <a

  let summary = [{
Compute the regularized incomplete beta integral \\(I_x(a, b)\\).
  }];

  let description = [{
The regularized incomplete beta integral is defined as:


\\(I_x(a, b) = \frac{B(x; a, b)}{B(a, b)}\\)

where


\\(B(x; a, b) = \int_0^x t^{a-1} (1 - t)^{b-1} dt\\)


is the incomplete beta function and \\(B(a, b)\\) is the *complete*
beta function.
  }];