Convergence

Nurzhan · March 9, 2015, 05:00

Dear Experts,

I need your help.

My target I could not get my result converged with the single precision (maximum 10^-5). However, the solution converged at each time-step, using the double-precision.

Could anyone please explain a reason to use the double-precision? Can you please refer any material about the single and double-precision so I can study it myself.

Regards,
Nurzhan

ghorrocks · March 9, 2015, 05:07

Numerical round-off. The double precision numeric resolves the small differences between numbers more accurately so the single precision simulation gets lost in noise generated by numerical round-off, but the double precision simulation has sufficient precision in the numbers to have the numerical noise at a low enough level that convergence is still possible.

Nurzhan · March 9, 2015, 19:25

Thank you, Glenn!

March 9, 2015, 05:00	Convergence	#1
Nurzhan Member Nurzhan Join Date: Jan 2014 Posts: 56 Rep Power: 12	Dear Experts, I need your help. My target I could not get my result converged with the single precision (maximum 10^-5). However, the solution converged at each time-step, using the double-precision. Could anyone please explain a reason to use the double-precision? Can you please refer any material about the single and double-precision so I can study it myself. Regards, Nurzhan

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March 9, 2015, 05:07		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,696 Rep Power: 143	Numerical round-off. The double precision numeric resolves the small differences between numbers more accurately so the single precision simulation gets lost in noise generated by numerical round-off, but the double precision simulation has sufficient precision in the numbers to have the numerical noise at a low enough level that convergence is still possible.

March 9, 2015, 19:25		#3
Nurzhan Member Nurzhan Join Date: Jan 2014 Posts: 56 Rep Power: 12	Thank you, Glenn!