perl58 -e "for(-15..16) { $eps=1; while( qq[1E$_] < qq[1E$_] + $eps )
           { $eps /= 2; } printf '%20.20f : %32.32f' . $/, qq[1E$_], $eps }"
0.00000000000000100000 : 0.00000000000000000000000000000010
0.00000000000001000000 : 0.00000000000000000000000000000039
0.00000000000010000000 : 0.00000000000000000000000000000631
0.00000000000100000000 : 0.00000000000000000000000000005049
0.00000000001000000000 : 0.00000000000000000000000000040390
0.00000000010000000000 : 0.00000000000000000000000000323117
0.00000000100000000000 : 0.00000000000000000000000005169879
0.00000001000000000000 : 0.00000000000000000000000082718061
0.00000010000000000000 : 0.00000000000000000000000661744490
0.00000100000000000000 : 0.00000000000000000000005293955920
0.00001000000000000000 : 0.00000000000000000000042351647363
0.00010000000000000000 : 0.00000000000000000000338813178902
0.00100000000000000000 : 0.00000000000000000010842021724855
0.01000000000000000000 : 0.00000000000000000043368086899420
0.10000000000000001000 : 0.00000000000000000693889390390723
1.00000000000000000000 : 0.00000000000000011102230246251565
10.00000000000000000000 : 0.00000000000000088817841970012523
100.00000000000000000000 : 0.00000000000000710542735760100190
1000.00000000000000000000 : 0.00000000000005684341886080801500
10000.00000000000000000000 : 0.00000000000090949470177292824000
100000.00000000000000000000 : 0.00000000000727595761418342590000
1000000.00000000000000000000 : 0.00000000005820766091346740700000
10000000.00000000000000000000 : 0.00000000093132257461547852000000
100000000.00000000000000000000 : 0.00000000745058059692382810000000
1000000000.00000000000000000000 : 0.00000005960464477539062500000000
10000000000.00000000000000000000 : 0.00000095367431640625000000000000
100000000000.00000000000000000000 : 0.00000762939453125000000000000000
1000000000000.00000000000000000000 : 0.00006103515625000000000000000000
10000000000000.00000000000000000000 : 0.00097656250000000000000000000000
100000000000000.00000000000000000000 : 0.00781250000000000000000000000000
1000000000000000.00000000000000000000 : 0.06250000000000000000000000000000
10000000000000000.00000000000000000000 : 1.00000000000000000000000000000000