casperyc

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11 years, 321 days

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These are replies submitted by casperyc

@Markiyan Hirnyk Thanks! Rather unual way, but works perfectly fine!

@acer On my i7 4790K system, I just did a quick test with n=8000.
 I ran in order these commands from a fresh start kernel:

 

n = 8000
m = RandomReal[{}, {n, n}];

SingularValueDecomposition[m]; // AbsoluteTiming

     {207.795, Null}

MatrixRank[m]; // AbsoluteTiming

    {25.5141, Null}

 

Note that since Version 5.0 (released in 2003), SingularValues has been superseded by SingularValueList and SingularValueDecomposition.

 

If you dont mind creat a Mathematica test file and instructions, for example, I shall run SingularValueDecomposition and MatrixRank seperately from fresh kernels? I can test them on my i7 940X system.

 

 

@acer

Digged up my "old" laptop:

i7 940X

4G RAM

Windows 7 SP1 X64 Ultimate -- English

 

Code used for Mathematica:

n=7000;

m = RandomReal[{}, {n, n}];

MatrixRank[m] // AbsoluteTiming

 

So here are some results:

Mathematica 9.0 - 148 sec

Mathematica 10.0.2 - 142 sec

Mathematica 10.1 - 51 sec

 

with n = 8000;

Mathematica 9.0 - 234 sec

Mathematica 10.0.2 - 231 sec

Mathematica 10.1 - 79 sec

 

@tomleslie Something like this?

@Alejandro Jakubi Thanks. This was taken from a Chinese site. I didn't do much thinking. I will forward your comments.

@acer I only used the code as given by the author from http://12000.org/my_notes/rankTest/test.htm .

I just thought it would be comparable since I have used the same code. Yes, I am aware the versions of MMA are different. But the results were just superising since there was a huge difference. I do have a copy of MMA 10.0.1, which I can test later.

 

I will post more information when I have time. Just for information, my system is i7 4970K, GTX980M, 32G RAM, 250 SSD.

 

@Christopher2222 Do you have the Maple file and the Mathematica file for Kamke's ODEs? I would be interested to run them on my system.Thanks!

@casperyc With n=8000, Mathematica took 25 seconds while Maple used 169sec.

@Christopher2222 hmmmm. I will try some of the code on my system.

 

Could there be something wrong with the results?

 

Maple took nearly 2min (seems normal), but MMA only took 15 seconds?

 

 

@Alejandro Jakubi Thanks! But I would not find ODE solving interesting at all as we know that Mathematica is not good at this at all (at least for my research). I have only been using Mathematica for global optimization and doing some parallel computing, which I find it easier to setup than in Maple.

I hope that Maple would have something that benchmarks the system. I am not asking for some comparison between the two programs if that was not clear. So that I know for example, whether my desktop or my laptop is 'faster' in running Maple.

I wonder if this have been developed?

I know that Mathematica can do a benchmarking testing, but does Maple now have a similar test?

 

Thanks!

@Christopher2222 I have been trying to get a hold of it for ages. But I can't find it anywhere though.

 

I can't work it out in Maple either. As a comparison, Mathematica does seem to be able to work it out.

 

Also, Mathematica seem to be able to get some symbolic answer as well: (which might be helpful?)

 

I think this is a more general issue, rather than a corrupted installation.

When I was installing the update (18.02), it did not occur any error.

I would just call it a bug.

@Alejandro Jakubi

 

I learnt someting new, and possibly quite useful to my other simplifcation rules!

 

That's works OK, but I have to apply the "a::integer" when I code up the rules, so the substition rules (ss) looks like this now,

 

I tried to stick with the normal "ss", without the "a::integer". And doing the messy simplifcation at background using another procedure, something like this,

 

        seq(
            [a::integer*localss[i]= a*s[i],
            -a::integer*localss[i]=-a*s[i]]
            ,i=2..Dimension(localss)
        )

 

but the "a::integer" would not multiply into the terms,

 

Having said this, you solution is definitely a magic!

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