Questions tagged [tensor]
For questions involving computational modeling with tensors. The most common definitions of a tensor are a multilinear map or simply a multilinear array.
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Mathematica Package for validating effective string theory solution
I am asking for Mathematica package that given an input of:
symmetric matrix $G_{\mu\nu}$, antisymmetric matrix $B_{\mu\nu}$ and a scalar function $\Phi$
will check whether it is a solution to the one-...
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1
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Difference of tensors to construct a higher dimensional tensor in pytorch
Suppose I have two tensors $A_{i_1,\ldots,i_M}$ and $B_{j_1,\ldots,j_N}$ where $M \neq N$ in general. We can define a tensor $C_{i_1,\ldots,i_M,j_1,\ldots,j_N}$ by
$$
C_{i_1,\ldots,i_M,j_1,\ldots,j_N} ...
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How to implement the following operation in pytorch (tensor by equating indices)
I wasn't sure if I should post this on stackoverflow rather than here, but because I have to construct a specific tensor I think here is more suitable.
I have 2 tensors, $x \in \mathbb{R}^{M \times N \...
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Numerical Divergence of a Tensor Field in Spherical Coordinates
I want to calculate the divergence of a rank-2 tensor field $$\nabla \cdot T$$ defined on the surface of a sphere in spherical coordinates. As an example, let the field be given as follows :
...
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Is it possible to express an arbitrary tensor contraction in terms of BLAS routines?
I noticed that libraries like numpy and pytorch are able to perform arbitrary tensor contractions at speeds similar to comparably sized matrix multiplications. This leads me to believe that underneath ...
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Apply 3D Operator to Matrix and get new Matrix
Hopefully this question makes sense.
I know I can formulate an operator for a vector as a matrix, then apply that matrix to my vector to get a new vector. For example, if I define a left shift ...
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Numerical integration in Fourier space over 3D grid
I am attempting to implement a model outlined in this paper:
General magnetostatic shape–shape interactions
Background
This model allows the calculation of magnetostatic interaction energies between ...
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Rotation of Higher order Tensors
I have a $D$-way tensor of dimensions $n\times n \times \dots \times n$ $(D)$- times. I want to sum the First vectors in all directions. For example, let $\boldsymbol{H}$ is 3-way tensor of dimensions ...
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Normalisation in tensor networks
I am trying to implement the iTEBD algorithm for the $PXP$ model, i.e, the hamiltonian is
$$H = \sum_iP_{i-1}X_iP_{i+1}.$$
Here $P$ is the projector onto the ground state and $X$ is the usual pauli x ...
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Computing material derivated of tensor quantity
I would like to compute the material derivated of a tensor quantity, in the context of the finite volume method (FVM):
The equation is:
$$
\frac{\mathrm{d} \textbf{T}}{\mathrm{d} t} = \frac{\partial \...
user42626
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Converting a 4 rank matrix to 2 rank matrix after using tensorproduct
Let's say I have a 2x2 matrix (with symbols) called 'A'. Now, if do
B = sympy.tensorproduct(A,A)
print(sympy.shape(B))
I get,
...
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1
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Confusion about bilinear form for elasticity equation in deal.ii tutorial
I'm learning how to solve vector-valued problems with deal.II library. In particular, I'm looking at the following introduction from the official website https://www.dealii.org/current/doxygen/deal.II/...
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3D Matrix (Tensor) Operating On a 1D Vector
Say you have a tensor $T$ and the components are represented by a 3 by 3 by 3 matrix. And you want to use that tensor to map a vector $u$ into a new vector $s$, both of which are 3 by 1 column vectors....
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Scaling tensor approximation by symmetric tensor decomposition with SciPy's L-BFGS-B
I am trying to approximate a symmetric tensor of which the values are in the range of [1e-7,1e-4], by a symmetric tensor decomposition of lower rank. For this I am using the L-BFGS-B method in SciPy's ...
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4th order tensor rotation - sources to refer
I am trying to model a linear elastic material in Abaqus using a UMAT. For my application, I need to rotate the 6x6 compliance matrix for a given set of eigenvectors (or a rotation matrix). I came ...
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