Calculation speed with Mathematica 10

Questions
,
1

Hello,

A colleague has a problem :
When he runs a code with Mathematica 9 on i7-2600 cpu (4 cores / 8HT) it takes 1 min.
When he runs the same code with Mathematica 10 on i7-4810 cpu (4 cores / 8HT) it takes 30 min !
Is it normal to have a such computing time difference for the same calculation as the cpu is quite similar ?
If no, how to fix it ?

Thanks for your help
Best regards

2

It should go without saying that this type of issue is impossible to diagnose without an actual example. (I said it anyway.)

3

I thought it could come from a well known bug with multi-core and mathematica 10…
anyway, here is the code in attached file.

it takes 121 secondes to evaluate the entire notebook with mathematica 10.0
and on the SAME computer, it takes 5 secondes to evaluate the entire notebook with mathematica 9.0

the PC is a HP Elitebook 840 notebook / windows 7 SP1 64b / i5-5300U @ 2.3GHz CPU / 16 GB RAM

thanks for the help.

4

Though I am not quite sure about why you observe the difference in the speed, you may use the modified notebook to speed up your plot. One options is to use the PerformanceGoal option and the other is to use the ParallelTable to distribute the data generation over several kernels.

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5

Thank you Shenghui Yang for your help.

I’m not expert in mathematica but if your solutions improve a lot the speed, they do not produce the same result, unfortunately.
if you make a zoom around 0 you will see the that the plots with your methods gives much less details than the original plot…

I changed also mathematica 10.0 to 10.3 and the computation time went from 81s to 67s without changing a line of code…
then, it’s already better… but v9.0 is still better…

6

I do not know if this is a known issue. Posted in-house to appropriate graphics folk.

Follow-up: Bug report filed.

7

With the second workaround, you can combine two graphics with low resolution and high resolution together.

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8

Thank you Shenghui Yang for your help.
but my point is not to find a workaround but to show what is for me a bug… or a sort of…

I made a new comparison between Mathematica 9 and 10 (see code in attached file) :

I reduced the plot range to be sure that the plot results are comparable (same quality result).

I fixed also the number of points to 500 and the ploting method to “speed”.

I still have a big difference in term of computation time :

Mathematica 10 : 155s

Mathematica 9 : 6s !!!