# numerical precision in output file

I want to write the numerical results of a computation to a file which is to be read in Fortran. The data looks like:

oswf0={1/(E^(25/2) \[Pi]^(1/4)), 1/(E^(81/8) \[Pi]^(1/4)), 1/( E^8 \[Pi]^(1/4)), 1/(E^(49/8) \[Pi]^(1/4)), 1/(E^(9/2) \[Pi]^(1/4))}


and I write it out with

Export["oscillatorwf_n0.dat", N[oswf0, 50]]


but the ouput file looks like

2.79918439290959673893721788332716676696872559106e-6
0.000030094068318430211211425128144825612558205505948023
0.00025197454903091461102445530088385078965019945670456
0.0016430804571573454314321054224416885379324057884235
0.008344251073246413703289360250294637268362678784284


All of them have clearly different precisions (>50). Why is mathematica not consistent here? What am I overlooking? How can I get 50 digits of precision consistently?

Thanks a lot

If I understand your question correct, you actually want to have an Accuracy of 50 and not a Precision of 50.
If you use

Export["oscillatorwf_n0.dat", N[oswf0, {Infinity, 51}]]


the exported numbers will have a precision of 50 or less. (Less, if they end with zeros.)

2.79918439290959673893721788332716676696872559e-6
0.00003009406831843021121142512814482561255820550595
0.0002519745490309146110244553008838507896501994567
0.00164308045715734543143210542244168853793240578842
0.00834425107324641370328936025029463726836267878428

• exactly, thank you! I always confuse the two! – ftiaronsem Sep 4 '14 at 22:13
• @ftiaronsem I would encourage you to edit your question to clarify what is the output that you seek. – Michael E2 Sep 4 '14 at 22:27

If I understand what you want, the trouble is that final zeros are truncated. Using NumberForm can fix that.

oswf0 = {1/(E^(25/2) π^(1/4)), 1/(E^(81/8) π^(1/4)),
1/(E^8 π^(1/4)), 1/(E^(49/8) π^(1/4)), 1/(E^(9/2) π^(1/4))}

ExportString[
NumberForm[#, Round@Precision[#],
NumberFormat -> (Row[{#1, If[#3 == "", "", "e"], #3}] &)] & /@
N[oswf0, 50], "Table"]
(*
"2.7991843929095967389372178833271667669687255910600e-6
0.000030094068318430211211425128144825612558205505948023
0.00025197454903091461102445530088385078965019945670456
0.0016430804571573454314321054224416885379324057884235
0.0083442510732464137032893602502946372683626787842840"
*)