// output of ./demo/arith/shiftadd-exp-demo.cc:
// Description:
//% Shift-add algorithm for computing b^x

arg 1: 0.5 == x  [Argument for shift-add b^x computation]  default=0.5
arg 2: 2 == b  [Base of the logarithm]  default=2
arg 3: 16 == n  [Number of iterations]  default=16

 -1   0.00000000   0.00000000  +1.00000000  +0.00000000

  1   0.58496250   0.00000000  +1.00000000  +0.58496250
  2   0.32192809   0.00000000  +1.00000000  +0.32192809
  2   0.64385618   0.32192809  +1.25000000  +0.32192809
  3   0.49185309   0.32192809  +1.25000000  +0.16992500
  3   0.66177809   0.49185309  +1.40625000  +0.16992500
  4   0.57931593   0.49185309  +1.40625000  +0.08746284
  5   0.53624721   0.49185309  +1.40625000  +0.04439411
  6   0.51422090   0.49185309  +1.40625000  +0.02236781
  7   0.50308035   0.49185309  +1.40625000  +0.01122725
  8   0.49747764   0.49185309  +1.40625000  +0.00562454
  8   0.50310219   0.49747764  +1.41174316  +0.00562454
  9   0.50029266   0.49747764  +1.41174316  +0.00281501
 10   0.49888583   0.49747764  +1.41174316  +0.00140819
 10   0.50029403   0.49888583  +1.41312181  +0.00140819
 11   0.49959010   0.49888583  +1.41312181  +0.00070426
 11   0.50029437   0.49959010  +1.41381182  +0.00070426
 12   0.49994228   0.49959010  +1.41381182  +0.00035217
 12   0.50029446   0.49994228  +1.41415698  +0.00035217
 13   0.50011838   0.49994228  +1.41415698  +0.00017609
 14   0.50003033   0.49994228  +1.41415698  +0.00008805
 15   0.49998631   0.49994228  +1.41415698  +0.00004402
 15   0.50003034   0.49998631  +1.41420014  +0.00004402

 99   0.50000000   0.50000000  +1.41421356  +0.00000000

dl = -1.341644065155911392e-05
2**(-n) = 1.52587890625e-05