Parallele Computing - 2 vs. 4 processor speed












3












$begingroup$


I am evaluating a code which ends with Table having ParallelEvaluate of a function XXXX[phi, theta, si]. For a grid of 225 points, a normal 2 processor laptop is taking 7 h as compared to 8.30 h by a high end Xeon 4 processor computer. CPU and memory usage for laptop and computer are about 66% vs 99% and 700MB vs 900 MB respectively. Will be thankful for any suggestion on how to improve the evaluation speed on computer. Thanks



XX1 = Table[{ParallelEvaluate[XXXX[phi, theta, si]], phi, theta, 
si}, {phi, 0, Pi/4, Pi/56}, {theta, 0, ArcCot[Cos[phi]],
ArcCot[Cos[phi]]/14}, {si, 0 Pi, 0 Pi, 0}]









share|improve this question









$endgroup$

















    3












    $begingroup$


    I am evaluating a code which ends with Table having ParallelEvaluate of a function XXXX[phi, theta, si]. For a grid of 225 points, a normal 2 processor laptop is taking 7 h as compared to 8.30 h by a high end Xeon 4 processor computer. CPU and memory usage for laptop and computer are about 66% vs 99% and 700MB vs 900 MB respectively. Will be thankful for any suggestion on how to improve the evaluation speed on computer. Thanks



    XX1 = Table[{ParallelEvaluate[XXXX[phi, theta, si]], phi, theta, 
    si}, {phi, 0, Pi/4, Pi/56}, {theta, 0, ArcCot[Cos[phi]],
    ArcCot[Cos[phi]]/14}, {si, 0 Pi, 0 Pi, 0}]









    share|improve this question









    $endgroup$















      3












      3








      3





      $begingroup$


      I am evaluating a code which ends with Table having ParallelEvaluate of a function XXXX[phi, theta, si]. For a grid of 225 points, a normal 2 processor laptop is taking 7 h as compared to 8.30 h by a high end Xeon 4 processor computer. CPU and memory usage for laptop and computer are about 66% vs 99% and 700MB vs 900 MB respectively. Will be thankful for any suggestion on how to improve the evaluation speed on computer. Thanks



      XX1 = Table[{ParallelEvaluate[XXXX[phi, theta, si]], phi, theta, 
      si}, {phi, 0, Pi/4, Pi/56}, {theta, 0, ArcCot[Cos[phi]],
      ArcCot[Cos[phi]]/14}, {si, 0 Pi, 0 Pi, 0}]









      share|improve this question









      $endgroup$




      I am evaluating a code which ends with Table having ParallelEvaluate of a function XXXX[phi, theta, si]. For a grid of 225 points, a normal 2 processor laptop is taking 7 h as compared to 8.30 h by a high end Xeon 4 processor computer. CPU and memory usage for laptop and computer are about 66% vs 99% and 700MB vs 900 MB respectively. Will be thankful for any suggestion on how to improve the evaluation speed on computer. Thanks



      XX1 = Table[{ParallelEvaluate[XXXX[phi, theta, si]], phi, theta, 
      si}, {phi, 0, Pi/4, Pi/56}, {theta, 0, ArcCot[Cos[phi]],
      ArcCot[Cos[phi]]/14}, {si, 0 Pi, 0 Pi, 0}]






      performance-tuning parallelization






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 4 hours ago









      user49535user49535

      1465




      1465






















          1 Answer
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          $begingroup$

          Without knowing the exact function (I assume it's something fairly long, possibly involving integrals or differential equations), I can only make the following suggestions:



          It looks like you're using exact numbers. If this is necessary for your application, then there's probably not a lot you can do, but exact numbers usually slow things down substantially. If you can, use Real numbers (just place a dot after the numbers like {phi, 0., Pi/4., Pi/56.}. If you need more precision than that but don't necessarily require the infinite precision of exact numbers, you can also do this: {phi, 0`50, Pi/4`50, Pi/56`50}. This will give you 50 digits of precision to work with which should make your final answer pretty close to the exact answer.



          The other thing I would try is:



          XX1 = ParallelTable[
          {XXXX[phi, theta, si]], phi, theta, si},
          {phi, 0, Pi/4, Pi/56},
          {theta, 0, ArcCot[Cos[phi]], ArcCot[Cos[phi]]/14},
          {si, 0 Pi, 0 Pi, 0}
          ]


          I think that ParallelTable is a better way to handle this than ParallelEvaluate. On a trial function, I see about a 100x speedup. ParallelEvaluate is simply evaluating your exact same function 4 times at each data point rather than splitting the task into multiple threads.



          If you can, combine both things for the best speedup.



          I hope this helps a bit! There are some people on here that are amazing at optimizing, perhaps they will be able to improve the speed even more. If it's possible, I would recommend posting your XXXX function unless it's insanely long.






          share|improve this answer











          $endgroup$













          • $begingroup$
            Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
            $endgroup$
            – MassDefect
            2 hours ago








          • 1




            $begingroup$
            You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
            $endgroup$
            – Lukas Lang
            2 hours ago












          • $begingroup$
            @LukasLang Oh, I see! Thanks!
            $endgroup$
            – MassDefect
            1 hour ago










          • $begingroup$
            Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
            $endgroup$
            – user49535
            27 mins ago











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          1 Answer
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          1 Answer
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          active

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          5












          $begingroup$

          Without knowing the exact function (I assume it's something fairly long, possibly involving integrals or differential equations), I can only make the following suggestions:



          It looks like you're using exact numbers. If this is necessary for your application, then there's probably not a lot you can do, but exact numbers usually slow things down substantially. If you can, use Real numbers (just place a dot after the numbers like {phi, 0., Pi/4., Pi/56.}. If you need more precision than that but don't necessarily require the infinite precision of exact numbers, you can also do this: {phi, 0`50, Pi/4`50, Pi/56`50}. This will give you 50 digits of precision to work with which should make your final answer pretty close to the exact answer.



          The other thing I would try is:



          XX1 = ParallelTable[
          {XXXX[phi, theta, si]], phi, theta, si},
          {phi, 0, Pi/4, Pi/56},
          {theta, 0, ArcCot[Cos[phi]], ArcCot[Cos[phi]]/14},
          {si, 0 Pi, 0 Pi, 0}
          ]


          I think that ParallelTable is a better way to handle this than ParallelEvaluate. On a trial function, I see about a 100x speedup. ParallelEvaluate is simply evaluating your exact same function 4 times at each data point rather than splitting the task into multiple threads.



          If you can, combine both things for the best speedup.



          I hope this helps a bit! There are some people on here that are amazing at optimizing, perhaps they will be able to improve the speed even more. If it's possible, I would recommend posting your XXXX function unless it's insanely long.






          share|improve this answer











          $endgroup$













          • $begingroup$
            Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
            $endgroup$
            – MassDefect
            2 hours ago








          • 1




            $begingroup$
            You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
            $endgroup$
            – Lukas Lang
            2 hours ago












          • $begingroup$
            @LukasLang Oh, I see! Thanks!
            $endgroup$
            – MassDefect
            1 hour ago










          • $begingroup$
            Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
            $endgroup$
            – user49535
            27 mins ago
















          5












          $begingroup$

          Without knowing the exact function (I assume it's something fairly long, possibly involving integrals or differential equations), I can only make the following suggestions:



          It looks like you're using exact numbers. If this is necessary for your application, then there's probably not a lot you can do, but exact numbers usually slow things down substantially. If you can, use Real numbers (just place a dot after the numbers like {phi, 0., Pi/4., Pi/56.}. If you need more precision than that but don't necessarily require the infinite precision of exact numbers, you can also do this: {phi, 0`50, Pi/4`50, Pi/56`50}. This will give you 50 digits of precision to work with which should make your final answer pretty close to the exact answer.



          The other thing I would try is:



          XX1 = ParallelTable[
          {XXXX[phi, theta, si]], phi, theta, si},
          {phi, 0, Pi/4, Pi/56},
          {theta, 0, ArcCot[Cos[phi]], ArcCot[Cos[phi]]/14},
          {si, 0 Pi, 0 Pi, 0}
          ]


          I think that ParallelTable is a better way to handle this than ParallelEvaluate. On a trial function, I see about a 100x speedup. ParallelEvaluate is simply evaluating your exact same function 4 times at each data point rather than splitting the task into multiple threads.



          If you can, combine both things for the best speedup.



          I hope this helps a bit! There are some people on here that are amazing at optimizing, perhaps they will be able to improve the speed even more. If it's possible, I would recommend posting your XXXX function unless it's insanely long.






          share|improve this answer











          $endgroup$













          • $begingroup$
            Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
            $endgroup$
            – MassDefect
            2 hours ago








          • 1




            $begingroup$
            You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
            $endgroup$
            – Lukas Lang
            2 hours ago












          • $begingroup$
            @LukasLang Oh, I see! Thanks!
            $endgroup$
            – MassDefect
            1 hour ago










          • $begingroup$
            Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
            $endgroup$
            – user49535
            27 mins ago














          5












          5








          5





          $begingroup$

          Without knowing the exact function (I assume it's something fairly long, possibly involving integrals or differential equations), I can only make the following suggestions:



          It looks like you're using exact numbers. If this is necessary for your application, then there's probably not a lot you can do, but exact numbers usually slow things down substantially. If you can, use Real numbers (just place a dot after the numbers like {phi, 0., Pi/4., Pi/56.}. If you need more precision than that but don't necessarily require the infinite precision of exact numbers, you can also do this: {phi, 0`50, Pi/4`50, Pi/56`50}. This will give you 50 digits of precision to work with which should make your final answer pretty close to the exact answer.



          The other thing I would try is:



          XX1 = ParallelTable[
          {XXXX[phi, theta, si]], phi, theta, si},
          {phi, 0, Pi/4, Pi/56},
          {theta, 0, ArcCot[Cos[phi]], ArcCot[Cos[phi]]/14},
          {si, 0 Pi, 0 Pi, 0}
          ]


          I think that ParallelTable is a better way to handle this than ParallelEvaluate. On a trial function, I see about a 100x speedup. ParallelEvaluate is simply evaluating your exact same function 4 times at each data point rather than splitting the task into multiple threads.



          If you can, combine both things for the best speedup.



          I hope this helps a bit! There are some people on here that are amazing at optimizing, perhaps they will be able to improve the speed even more. If it's possible, I would recommend posting your XXXX function unless it's insanely long.






          share|improve this answer











          $endgroup$



          Without knowing the exact function (I assume it's something fairly long, possibly involving integrals or differential equations), I can only make the following suggestions:



          It looks like you're using exact numbers. If this is necessary for your application, then there's probably not a lot you can do, but exact numbers usually slow things down substantially. If you can, use Real numbers (just place a dot after the numbers like {phi, 0., Pi/4., Pi/56.}. If you need more precision than that but don't necessarily require the infinite precision of exact numbers, you can also do this: {phi, 0`50, Pi/4`50, Pi/56`50}. This will give you 50 digits of precision to work with which should make your final answer pretty close to the exact answer.



          The other thing I would try is:



          XX1 = ParallelTable[
          {XXXX[phi, theta, si]], phi, theta, si},
          {phi, 0, Pi/4, Pi/56},
          {theta, 0, ArcCot[Cos[phi]], ArcCot[Cos[phi]]/14},
          {si, 0 Pi, 0 Pi, 0}
          ]


          I think that ParallelTable is a better way to handle this than ParallelEvaluate. On a trial function, I see about a 100x speedup. ParallelEvaluate is simply evaluating your exact same function 4 times at each data point rather than splitting the task into multiple threads.



          If you can, combine both things for the best speedup.



          I hope this helps a bit! There are some people on here that are amazing at optimizing, perhaps they will be able to improve the speed even more. If it's possible, I would recommend posting your XXXX function unless it's insanely long.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 2 hours ago









          Lukas Lang

          6,6651930




          6,6651930










          answered 3 hours ago









          MassDefectMassDefect

          85128




          85128












          • $begingroup$
            Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
            $endgroup$
            – MassDefect
            2 hours ago








          • 1




            $begingroup$
            You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
            $endgroup$
            – Lukas Lang
            2 hours ago












          • $begingroup$
            @LukasLang Oh, I see! Thanks!
            $endgroup$
            – MassDefect
            1 hour ago










          • $begingroup$
            Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
            $endgroup$
            – user49535
            27 mins ago


















          • $begingroup$
            Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
            $endgroup$
            – MassDefect
            2 hours ago








          • 1




            $begingroup$
            You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
            $endgroup$
            – Lukas Lang
            2 hours ago












          • $begingroup$
            @LukasLang Oh, I see! Thanks!
            $endgroup$
            – MassDefect
            1 hour ago










          • $begingroup$
            Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
            $endgroup$
            – user49535
            27 mins ago
















          $begingroup$
          Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
          $endgroup$
          – MassDefect
          2 hours ago






          $begingroup$
          Thanks @LukasLang ! How do you type grave accents without it interpreting them as the inline code markers? I tried backslashes before them, but that didn’t help.
          $endgroup$
          – MassDefect
          2 hours ago






          1




          1




          $begingroup$
          You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
          $endgroup$
          – Lukas Lang
          2 hours ago






          $begingroup$
          You have to increase the amount of enclosing accents: ``` `` Codewithaccents`` ```. If you need double accents, you enclose the code with three, and so on (edit: for some reason, it doesn't work in the comment section - but you can edit your answer to see how it's done)
          $endgroup$
          – Lukas Lang
          2 hours ago














          $begingroup$
          @LukasLang Oh, I see! Thanks!
          $endgroup$
          – MassDefect
          1 hour ago




          $begingroup$
          @LukasLang Oh, I see! Thanks!
          $endgroup$
          – MassDefect
          1 hour ago












          $begingroup$
          Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
          $endgroup$
          – user49535
          27 mins ago




          $begingroup$
          Thanks both of you. three points 1. I do not necessary need to use exact values of (theta, phi) if it can speed up, can use ".". 2. I tried to use ParalleleTable first, but in contrast to your experience, it took 30h/48h for 4/2 processor computer as compared to 8h/7h for ParallelEvaluate. 4 - 8 times slower. 3. How can I combine both...you mean ParallelTable[ParallelEvaluate[. ??
          $endgroup$
          – user49535
          27 mins ago


















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