Tensor operations











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I'm trying to do some scientific programming, but I have limited math experience. My supervisor has given me the following equation I need to solve for $d$:
$$
Y = Xe^{-bcdot d}.
$$

where





  • $X$ and $Y$ are $96 times 96$ matrices,

  • and $b$ and $d$ are $3times 3$ matrices (the '$cdot$' sing above signifies dot product).


I'm not even sure how I would go about trying to solve for $d$. It doesn't seem to make sense to rearrange the equation above to
$$
d = mathrm{inv}(b) ln(X/Y),
$$

since (1) I'm not sure how dot product works with tensors (do I need to learn dyadic algebra to do this???), but I didn't think you could just do $mathrm{inv}(b)(bcdot d)$. And how are you supposed to end up with a $3times 3$ matrix if you're multiplying a $3times 3$ matrix by a $96times 96$ one?



If anyone could please give suggest some resources or give me some direction, I would be sincerely appreciative, and thank you for your time.










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  • Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
    – greg
    Nov 15 at 17:40












  • That is exactly what it was :) Thank you so much.
    – Pendelluft
    2 days ago















up vote
1
down vote

favorite












I'm trying to do some scientific programming, but I have limited math experience. My supervisor has given me the following equation I need to solve for $d$:
$$
Y = Xe^{-bcdot d}.
$$

where





  • $X$ and $Y$ are $96 times 96$ matrices,

  • and $b$ and $d$ are $3times 3$ matrices (the '$cdot$' sing above signifies dot product).


I'm not even sure how I would go about trying to solve for $d$. It doesn't seem to make sense to rearrange the equation above to
$$
d = mathrm{inv}(b) ln(X/Y),
$$

since (1) I'm not sure how dot product works with tensors (do I need to learn dyadic algebra to do this???), but I didn't think you could just do $mathrm{inv}(b)(bcdot d)$. And how are you supposed to end up with a $3times 3$ matrix if you're multiplying a $3times 3$ matrix by a $96times 96$ one?



If anyone could please give suggest some resources or give me some direction, I would be sincerely appreciative, and thank you for your time.










share|cite|improve this question
























  • Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
    – greg
    Nov 15 at 17:40












  • That is exactly what it was :) Thank you so much.
    – Pendelluft
    2 days ago













up vote
1
down vote

favorite









up vote
1
down vote

favorite











I'm trying to do some scientific programming, but I have limited math experience. My supervisor has given me the following equation I need to solve for $d$:
$$
Y = Xe^{-bcdot d}.
$$

where





  • $X$ and $Y$ are $96 times 96$ matrices,

  • and $b$ and $d$ are $3times 3$ matrices (the '$cdot$' sing above signifies dot product).


I'm not even sure how I would go about trying to solve for $d$. It doesn't seem to make sense to rearrange the equation above to
$$
d = mathrm{inv}(b) ln(X/Y),
$$

since (1) I'm not sure how dot product works with tensors (do I need to learn dyadic algebra to do this???), but I didn't think you could just do $mathrm{inv}(b)(bcdot d)$. And how are you supposed to end up with a $3times 3$ matrix if you're multiplying a $3times 3$ matrix by a $96times 96$ one?



If anyone could please give suggest some resources or give me some direction, I would be sincerely appreciative, and thank you for your time.










share|cite|improve this question















I'm trying to do some scientific programming, but I have limited math experience. My supervisor has given me the following equation I need to solve for $d$:
$$
Y = Xe^{-bcdot d}.
$$

where





  • $X$ and $Y$ are $96 times 96$ matrices,

  • and $b$ and $d$ are $3times 3$ matrices (the '$cdot$' sing above signifies dot product).


I'm not even sure how I would go about trying to solve for $d$. It doesn't seem to make sense to rearrange the equation above to
$$
d = mathrm{inv}(b) ln(X/Y),
$$

since (1) I'm not sure how dot product works with tensors (do I need to learn dyadic algebra to do this???), but I didn't think you could just do $mathrm{inv}(b)(bcdot d)$. And how are you supposed to end up with a $3times 3$ matrix if you're multiplying a $3times 3$ matrix by a $96times 96$ one?



If anyone could please give suggest some resources or give me some direction, I would be sincerely appreciative, and thank you for your time.







matrix-equations tensors matrix-calculus






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edited Nov 15 at 6:11









Daniele Tampieri

1,5451619




1,5451619










asked Nov 15 at 5:04









Pendelluft

62




62












  • Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
    – greg
    Nov 15 at 17:40












  • That is exactly what it was :) Thank you so much.
    – Pendelluft
    2 days ago


















  • Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
    – greg
    Nov 15 at 17:40












  • That is exactly what it was :) Thank you so much.
    – Pendelluft
    2 days ago
















Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
– greg
Nov 15 at 17:40






Perhaps the notation $(bcdot d)$ is meant to denote the scalar product of the two matrices, i.e. $$bcdot d = sum_{ij} b_{ij}d_{ij}$$
– greg
Nov 15 at 17:40














That is exactly what it was :) Thank you so much.
– Pendelluft
2 days ago




That is exactly what it was :) Thank you so much.
– Pendelluft
2 days ago















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