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Double Precision and Modules

Double Precision and Modules

Double Precision and Modules


very new to Fortran but have written the code attached. However it doesn't seem to run with double precision unless I use the old style method of writing 0d0 and implicit double precision at the top of the subroutines. I have tried to use a module and declare everything in it to be double precision but this doesn't work.

When it runs with double precision the final answer is 2.828427124751.

 Have I made some really obvious error or why does this not work? I don't want to use the old Fortran methods so any help is really appreciated,


RE: Double Precision and Modules

selected_real_kind(p=7) only gives 7 significant figures but your answer is 13 significant figures.  I don't know if it has that level of accuracy.  What answer are you getting?  I'm getting 2.828427157712.  The last 5 digits are different but the first 8 are the same.

RE: Double Precision and Modules

Instead of
integer, parameter :: dbl = selected_real_kind(p=7)
integer, parameter :: dbl = selected_real_kind(1.D0)

and specify all real constants like 0.1 as 0.1_dbl  

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