Unable to determine Sobolev space











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I have the following function:



$T ( textbf{r}) = frac{q}{4 pi k} int_{s_i=0}^{L_i} frac{1}{left| textbf{r}-textbf{r}'right|} ds_i = frac{q}{4 pi k} logleft( frac{tan(theta_2/2)}{tan(theta_1/2)} right)$



which is the exact temperature field produced by a heat source of magnitude $q$ applied over a line (see figure)



enter image description here



I would like to know what's the space this function lies on. To that end, I set the line source between $(-2,0)--(2,0)$ and I consider my domain as $[0,1]times[0,1]$ (since the solution is symmetric and thus I can multiply by $4$ the result. I decided to use Mathematica to see whether I could integrate the function squared, and indeed I get a finite value, for which I conclude the function is at least in $L^2$ ($H^0$). However, if I obtain the gradient of the function, it seems that the $y$-component does not give a finite value if I numerically integrate it with exponent $2$. If I integrate it numerically with exponent $1$ Mathematica gives me the following message:



NIntegrate: ""NIntegrate failed to converge to prescribed accuracy after 18 
recursive bisections in y near {x,y} = {0.844124,2.*10^-323}.
NIntegrate obtained -118.498 and 0.010644969997020758` for the
integral and error estimates.""
-118.498


and any other exponent returns even complex numbers. So at this point I am clueless. How can I tell exactly what's the Sobolev space this function lies on?










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    up vote
    0
    down vote

    favorite












    I have the following function:



    $T ( textbf{r}) = frac{q}{4 pi k} int_{s_i=0}^{L_i} frac{1}{left| textbf{r}-textbf{r}'right|} ds_i = frac{q}{4 pi k} logleft( frac{tan(theta_2/2)}{tan(theta_1/2)} right)$



    which is the exact temperature field produced by a heat source of magnitude $q$ applied over a line (see figure)



    enter image description here



    I would like to know what's the space this function lies on. To that end, I set the line source between $(-2,0)--(2,0)$ and I consider my domain as $[0,1]times[0,1]$ (since the solution is symmetric and thus I can multiply by $4$ the result. I decided to use Mathematica to see whether I could integrate the function squared, and indeed I get a finite value, for which I conclude the function is at least in $L^2$ ($H^0$). However, if I obtain the gradient of the function, it seems that the $y$-component does not give a finite value if I numerically integrate it with exponent $2$. If I integrate it numerically with exponent $1$ Mathematica gives me the following message:



    NIntegrate: ""NIntegrate failed to converge to prescribed accuracy after 18 
    recursive bisections in y near {x,y} = {0.844124,2.*10^-323}.
    NIntegrate obtained -118.498 and 0.010644969997020758` for the
    integral and error estimates.""
    -118.498


    and any other exponent returns even complex numbers. So at this point I am clueless. How can I tell exactly what's the Sobolev space this function lies on?










    share|cite|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I have the following function:



      $T ( textbf{r}) = frac{q}{4 pi k} int_{s_i=0}^{L_i} frac{1}{left| textbf{r}-textbf{r}'right|} ds_i = frac{q}{4 pi k} logleft( frac{tan(theta_2/2)}{tan(theta_1/2)} right)$



      which is the exact temperature field produced by a heat source of magnitude $q$ applied over a line (see figure)



      enter image description here



      I would like to know what's the space this function lies on. To that end, I set the line source between $(-2,0)--(2,0)$ and I consider my domain as $[0,1]times[0,1]$ (since the solution is symmetric and thus I can multiply by $4$ the result. I decided to use Mathematica to see whether I could integrate the function squared, and indeed I get a finite value, for which I conclude the function is at least in $L^2$ ($H^0$). However, if I obtain the gradient of the function, it seems that the $y$-component does not give a finite value if I numerically integrate it with exponent $2$. If I integrate it numerically with exponent $1$ Mathematica gives me the following message:



      NIntegrate: ""NIntegrate failed to converge to prescribed accuracy after 18 
      recursive bisections in y near {x,y} = {0.844124,2.*10^-323}.
      NIntegrate obtained -118.498 and 0.010644969997020758` for the
      integral and error estimates.""
      -118.498


      and any other exponent returns even complex numbers. So at this point I am clueless. How can I tell exactly what's the Sobolev space this function lies on?










      share|cite|improve this question













      I have the following function:



      $T ( textbf{r}) = frac{q}{4 pi k} int_{s_i=0}^{L_i} frac{1}{left| textbf{r}-textbf{r}'right|} ds_i = frac{q}{4 pi k} logleft( frac{tan(theta_2/2)}{tan(theta_1/2)} right)$



      which is the exact temperature field produced by a heat source of magnitude $q$ applied over a line (see figure)



      enter image description here



      I would like to know what's the space this function lies on. To that end, I set the line source between $(-2,0)--(2,0)$ and I consider my domain as $[0,1]times[0,1]$ (since the solution is symmetric and thus I can multiply by $4$ the result. I decided to use Mathematica to see whether I could integrate the function squared, and indeed I get a finite value, for which I conclude the function is at least in $L^2$ ($H^0$). However, if I obtain the gradient of the function, it seems that the $y$-component does not give a finite value if I numerically integrate it with exponent $2$. If I integrate it numerically with exponent $1$ Mathematica gives me the following message:



      NIntegrate: ""NIntegrate failed to converge to prescribed accuracy after 18 
      recursive bisections in y near {x,y} = {0.844124,2.*10^-323}.
      NIntegrate obtained -118.498 and 0.010644969997020758` for the
      integral and error estimates.""
      -118.498


      and any other exponent returns even complex numbers. So at this point I am clueless. How can I tell exactly what's the Sobolev space this function lies on?







      sobolev-spaces fractional-sobolev-spaces






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      asked Nov 22 at 16:25









      Alejandro Marcos Aragon

      1084




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