Help understanding equation with $nabla_hat{x}$












0












$begingroup$


I have the following defined:



$hat{x} leftarrow epsilon x + (1-epsilon)tilde{x}$



and then this:



$lambda(||nabla_hat{x}D_w(hat{x})||_2-1)^2$



Now this is something I have to implement into a computer program, and I think I've got most of it, with the exception of $nabla_hat{x}$



All of the different x are vectors



Could someone please help me understand what it means?

Thank you in advance!



Edit for clarifications:




  • I'm implementing a Wasserstein GAN from the following paper: (https://arxiv.org/abs/1704.00028). Section 4, page 4, equation 3 contains the equation in question


  • $D_w$ is a neural network ( The discriminator in a GAN )


  • The second equation is something the authors of the paper have called Gradient Penalty and is supposed to be added to the calculated loss used to train the algorithm.











share|cite|improve this question











$endgroup$












  • $begingroup$
    What is w in that expression?
    $endgroup$
    – I like Serena
    Jan 17 at 8:32










  • $begingroup$
    Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
    $endgroup$
    – Aleksejs Fomins
    Jan 17 at 8:46










  • $begingroup$
    Edited question to clarify :-)
    $endgroup$
    – Covey
    Jan 17 at 9:28
















0












$begingroup$


I have the following defined:



$hat{x} leftarrow epsilon x + (1-epsilon)tilde{x}$



and then this:



$lambda(||nabla_hat{x}D_w(hat{x})||_2-1)^2$



Now this is something I have to implement into a computer program, and I think I've got most of it, with the exception of $nabla_hat{x}$



All of the different x are vectors



Could someone please help me understand what it means?

Thank you in advance!



Edit for clarifications:




  • I'm implementing a Wasserstein GAN from the following paper: (https://arxiv.org/abs/1704.00028). Section 4, page 4, equation 3 contains the equation in question


  • $D_w$ is a neural network ( The discriminator in a GAN )


  • The second equation is something the authors of the paper have called Gradient Penalty and is supposed to be added to the calculated loss used to train the algorithm.











share|cite|improve this question











$endgroup$












  • $begingroup$
    What is w in that expression?
    $endgroup$
    – I like Serena
    Jan 17 at 8:32










  • $begingroup$
    Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
    $endgroup$
    – Aleksejs Fomins
    Jan 17 at 8:46










  • $begingroup$
    Edited question to clarify :-)
    $endgroup$
    – Covey
    Jan 17 at 9:28














0












0








0





$begingroup$


I have the following defined:



$hat{x} leftarrow epsilon x + (1-epsilon)tilde{x}$



and then this:



$lambda(||nabla_hat{x}D_w(hat{x})||_2-1)^2$



Now this is something I have to implement into a computer program, and I think I've got most of it, with the exception of $nabla_hat{x}$



All of the different x are vectors



Could someone please help me understand what it means?

Thank you in advance!



Edit for clarifications:




  • I'm implementing a Wasserstein GAN from the following paper: (https://arxiv.org/abs/1704.00028). Section 4, page 4, equation 3 contains the equation in question


  • $D_w$ is a neural network ( The discriminator in a GAN )


  • The second equation is something the authors of the paper have called Gradient Penalty and is supposed to be added to the calculated loss used to train the algorithm.











share|cite|improve this question











$endgroup$




I have the following defined:



$hat{x} leftarrow epsilon x + (1-epsilon)tilde{x}$



and then this:



$lambda(||nabla_hat{x}D_w(hat{x})||_2-1)^2$



Now this is something I have to implement into a computer program, and I think I've got most of it, with the exception of $nabla_hat{x}$



All of the different x are vectors



Could someone please help me understand what it means?

Thank you in advance!



Edit for clarifications:




  • I'm implementing a Wasserstein GAN from the following paper: (https://arxiv.org/abs/1704.00028). Section 4, page 4, equation 3 contains the equation in question


  • $D_w$ is a neural network ( The discriminator in a GAN )


  • The second equation is something the authors of the paper have called Gradient Penalty and is supposed to be added to the calculated loss used to train the algorithm.








linear-algebra






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share|cite|improve this question













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share|cite|improve this question








edited Jan 17 at 13:16







Covey

















asked Jan 17 at 8:13









CoveyCovey

32




32












  • $begingroup$
    What is w in that expression?
    $endgroup$
    – I like Serena
    Jan 17 at 8:32










  • $begingroup$
    Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
    $endgroup$
    – Aleksejs Fomins
    Jan 17 at 8:46










  • $begingroup$
    Edited question to clarify :-)
    $endgroup$
    – Covey
    Jan 17 at 9:28


















  • $begingroup$
    What is w in that expression?
    $endgroup$
    – I like Serena
    Jan 17 at 8:32










  • $begingroup$
    Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
    $endgroup$
    – Aleksejs Fomins
    Jan 17 at 8:46










  • $begingroup$
    Edited question to clarify :-)
    $endgroup$
    – Covey
    Jan 17 at 9:28
















$begingroup$
What is w in that expression?
$endgroup$
– I like Serena
Jan 17 at 8:32




$begingroup$
What is w in that expression?
$endgroup$
– I like Serena
Jan 17 at 8:32












$begingroup$
Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
$endgroup$
– Aleksejs Fomins
Jan 17 at 8:46




$begingroup$
Would you be so kind to give some context? What is the general meaning of the 2nd equation, and what do you mean by implementing a computer program? Do you intend to, for example, solve a differential equation, or calculate the value of some known expression?
$endgroup$
– Aleksejs Fomins
Jan 17 at 8:46












$begingroup$
Edited question to clarify :-)
$endgroup$
– Covey
Jan 17 at 9:28




$begingroup$
Edited question to clarify :-)
$endgroup$
– Covey
Jan 17 at 9:28










1 Answer
1






active

oldest

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0












$begingroup$

In Linear Algebra the operator in question is called the Del operator, $nabla$ , and is defined such that:



$nabla = frac{partial}{partial x}mathbf{i} + frac{partial}{partial y}mathbf{j} + frac{partial}{partial z}mathbf{k}$.



The subscript used in your equation is $hat{x}$, but what is the vector in question. From what I can understand you have del acting on this function $D_{w}(hat{x})$ but the subscript might be restricting or changing what coordinate system Del is acting in.



I hope this helps.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Oh right. Thank you - this definitely helps!
    $endgroup$
    – Covey
    Jan 18 at 9:09











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

In Linear Algebra the operator in question is called the Del operator, $nabla$ , and is defined such that:



$nabla = frac{partial}{partial x}mathbf{i} + frac{partial}{partial y}mathbf{j} + frac{partial}{partial z}mathbf{k}$.



The subscript used in your equation is $hat{x}$, but what is the vector in question. From what I can understand you have del acting on this function $D_{w}(hat{x})$ but the subscript might be restricting or changing what coordinate system Del is acting in.



I hope this helps.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Oh right. Thank you - this definitely helps!
    $endgroup$
    – Covey
    Jan 18 at 9:09
















0












$begingroup$

In Linear Algebra the operator in question is called the Del operator, $nabla$ , and is defined such that:



$nabla = frac{partial}{partial x}mathbf{i} + frac{partial}{partial y}mathbf{j} + frac{partial}{partial z}mathbf{k}$.



The subscript used in your equation is $hat{x}$, but what is the vector in question. From what I can understand you have del acting on this function $D_{w}(hat{x})$ but the subscript might be restricting or changing what coordinate system Del is acting in.



I hope this helps.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Oh right. Thank you - this definitely helps!
    $endgroup$
    – Covey
    Jan 18 at 9:09














0












0








0





$begingroup$

In Linear Algebra the operator in question is called the Del operator, $nabla$ , and is defined such that:



$nabla = frac{partial}{partial x}mathbf{i} + frac{partial}{partial y}mathbf{j} + frac{partial}{partial z}mathbf{k}$.



The subscript used in your equation is $hat{x}$, but what is the vector in question. From what I can understand you have del acting on this function $D_{w}(hat{x})$ but the subscript might be restricting or changing what coordinate system Del is acting in.



I hope this helps.






share|cite|improve this answer









$endgroup$



In Linear Algebra the operator in question is called the Del operator, $nabla$ , and is defined such that:



$nabla = frac{partial}{partial x}mathbf{i} + frac{partial}{partial y}mathbf{j} + frac{partial}{partial z}mathbf{k}$.



The subscript used in your equation is $hat{x}$, but what is the vector in question. From what I can understand you have del acting on this function $D_{w}(hat{x})$ but the subscript might be restricting or changing what coordinate system Del is acting in.



I hope this helps.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 17 at 13:38









C_RichmondC_Richmond

863




863












  • $begingroup$
    Oh right. Thank you - this definitely helps!
    $endgroup$
    – Covey
    Jan 18 at 9:09


















  • $begingroup$
    Oh right. Thank you - this definitely helps!
    $endgroup$
    – Covey
    Jan 18 at 9:09
















$begingroup$
Oh right. Thank you - this definitely helps!
$endgroup$
– Covey
Jan 18 at 9:09




$begingroup$
Oh right. Thank you - this definitely helps!
$endgroup$
– Covey
Jan 18 at 9:09


















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