using an optimally-precise Pow: 1: rounded = 1, both = 1.00000000000000000000, delta = +0.00000000000000000000e+00 2: rounded = 1, both = 1.00000000000000000000, delta = +0.00000000000000000000e+00 3: rounded = 2, both = 2.00000000000000000000, delta = +0.00000000000000000000e+00 4: rounded = 3, both = 3.00000000000000000000, delta = +0.00000000000000000000e+00 5: rounded = 5, both = 5.00000000000000000000, delta = +0.00000000000000000000e+00 6: rounded = 8, both = 8.00000000000000000000, delta = +0.00000000000000000000e+00 7: rounded = 13, both = 13.00000000000000000000, delta = +0.00000000000000000000e+00 8: rounded = 21, both = 21.00000000000000000000, delta = +0.00000000000000000000e+00 9: rounded = 34, both = 34.00000000000000000000, delta = +0.00000000000000000000e+00 10: rounded = 55, both = 55.00000000000000000000, delta = +0.00000000000000000000e+00 11: rounded = 89, both = 89.00000000000000000000, delta = +0.00000000000000000000e+00 12: rounded = 144, both = 144.00000000000000000000, delta = +0.00000000000000000000e+00 13: rounded = 233, both = 233.00000000000000000000, delta = +0.00000000000000000000e+00 14: rounded = 377, both = 377.00000000000005684342, delta = +5.68434188608080148697e-14 15: rounded = 610, both = 610.00000000000000000000, delta = +0.00000000000000000000e+00 16: rounded = 987, both = 986.99999999999977262632, delta = -2.27373675443232059479e-13 17: rounded = 1597, both = 1596.99999999999977262632, delta = -2.27373675443232059479e-13 18: rounded = 2584, both = 2584.00000000000000000000, delta = +0.00000000000000000000e+00 19: rounded = 4181, both = 4181.00000000000000000000, delta = +0.00000000000000000000e+00 20: rounded = 6765, both = 6765.00000000000090949470, delta = +9.09494701772928237915e-13 21: rounded = 10946, both = 10946.00000000000363797881, delta = +3.63797880709171295166e-12 22: rounded = 17711, both = 17711.00000000000000000000, delta = +0.00000000000000000000e+00 23: rounded = 28657, both = 28657.00000000000363797881, delta = +3.63797880709171295166e-12 24: rounded = 46368, both = 46368.00000000000727595761, delta = +7.27595761418342590332e-12 25: rounded = 75025, both = 75025.00000000001455191523, delta = +1.45519152283668518066e-11 26: rounded = 121393, both = 121393.00000000001455191523, delta = +1.45519152283668518066e-11 27: rounded = 196418, both = 196418.00000000005820766091, delta = +5.82076609134674072266e-11 28: rounded = 317811, both = 317811.00000000011641532183, delta = +1.16415321826934814453e-10 29: rounded = 514229, both = 514228.99999999994179233909, delta = -5.82076609134674072266e-11 30: rounded = 832040, both = 832040.00000000000000000000, delta = +0.00000000000000000000e+00 31: rounded = 1346269, both = 1346269.00000000046566128731, delta = +4.65661287307739257812e-10 32: rounded = 2178309, both = 2178309.00000000000000000000, delta = +0.00000000000000000000e+00 33: rounded = 3524578, both = 3524577.99999999906867742538, delta = 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53316291173.00003051757812500000, delta = +3.05175781250000000000e-05 54: rounded = 86267571272, both = 86267571272.00003051757812500000, delta = +3.05175781250000000000e-05 55: rounded = 139583862445, both = 139583862445.00006103515625000000, delta = +6.10351562500000000000e-05 56: rounded = 225851433717, both = 225851433717.00018310546875000000, delta = +1.83105468750000000000e-04 57: rounded = 365435296162, both = 365435296162.00024414062500000000, delta = +2.44140625000000000000e-04 58: rounded = 591286729879, both = 591286729878.99987792968750000000, delta = -1.22070312500000000000e-04 59: rounded = 956722026041, both = 956722026041.00073242187500000000, delta = +7.32421875000000000000e-04 60: rounded = 1548008755920, both = 1548008755920.00024414062500000000, delta = +2.44140625000000000000e-04 61: rounded = 2504730781961, both = 2504730781960.99902343750000000000, delta = -9.76562500000000000000e-04 62: rounded = 4052739537881, both = 4052739537881.00341796875000000000, delta = 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23416728348467700.00000000000000000000, delta = +0.00000000000000000000e+00 81: rounded = 37889062373143904, both = 37889062373143904.00000000000000000000, delta = +0.00000000000000000000e+00 82: rounded = 61305790721611608, both = 61305790721611608.00000000000000000000, delta = +0.00000000000000000000e+00 83: rounded = 99194853094755536, both = 99194853094755536.00000000000000000000, delta = +0.00000000000000000000e+00 84: rounded = 160500643816367264, both = 160500643816367264.00000000000000000000, delta = +0.00000000000000000000e+00 85: rounded = 259695496911122752, both = 259695496911122752.00000000000000000000, delta = +0.00000000000000000000e+00 86: rounded = 420196140727489984, both = 420196140727489984.00000000000000000000, delta = +0.00000000000000000000e+00 87: rounded = 679891637638612608, both = 679891637638612608.00000000000000000000, delta = +0.00000000000000000000e+00 88: rounded = 1100087778366102528, both = 1100087778366102528.00000000000000000000, delta = 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On Mon, Apr 30, 2018 at 2:40 PM andrey mirtchovski <mirtchov...@gmail.com> wrote: > > math.Pow does not give as precise answers as the C++ std lib. > > math pow doesn't just multiply X by itself Y times, it uses a > different algorithm: > > https://golang.org/src/math/pow.go#L40 > > it would perhaps make sense to quantify the error margins that this > algorithm introduces. > > not sure what c++ stdlib does. > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Michael T. Jones michael.jo...@gmail.com -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
