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Questions tagged [elementwise-operations]

204 questions
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How can I do an element-wise sum of several arrays in Java inside a stream?

I want to stream a list of objects, each of which contain a series of integers of the same size. Then I want to do an element-wise sum of all the lists, reulting into a single list of the same size. It should be something like…
Rayamon
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Numpy Value Error: Elementwise Operations on Meshgrid

Given my code below: import numpy as np nx, ny, nz = (50, 50, 50) x = np.linspace(1, 2, nx) y = np.linspace(2, 3, ny) z = np.linspace(0, 1, nz) xg, yg, zg = np.meshgrid(x, y, z) def fun(x, y, z, a, b, c): r = np.array([x, y, z]) r0 =…
Sterling Butters
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Jacobian of theano scan creates named copies of symbolic variables, resulting in wrongly assigned inputs and UnusedInputError

I have a model in which rates of a random (Poisson) process are distributed according to a function p_nu(gamma,delta,nu_max). With pymc3/theano I want to obtain the posterior distribution of gamma,delta,nu_max when observing N_AP events (N_AP being…
wollex
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Element-wise multidimension matrix multiplication with broadcasting in python

Is there a efficient (numpy function) way to do element-wise matrix multiplication of two different-sized arrays that will broadcast into a new array. e.g., a = np.arange(24).reshape((2,12)) #gives a 2x12 array b = np.arange(36).reshape((3,12))…
bigwillis234
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NP Array Comparison elementwise and specific conditions

I would like to ask a question for a numpy array below. I have a dataset, which has 50 rows and 15 columns and I created a numpy array as such: I want to compare rows with each other (except than itself), then found the number of rows which…
Dinc Kirikci
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Numpy Array Comparison (Python)

I would like to ask a question for a numpy array below. I have a dataset, which has 50 rows and 15 columns and I created a numpy array as such: x=x.to_numpy() I want to compare rows with each other (except than itself), then found the number of…
Dinc Kirikci
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Element-wise comparison of numpy arrays (Python)

I would like to ask a question for a numpy array below. I have a dataset, which has 50 rows and 15 columns and I created a numpy array as such: x=x.to_numpy() My aim is compare each row with other rows(elementwise and except itself) and find…
Dinc Kirikci
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Multiply matrix by vector rowwise (sweep)

Does STAN provide a method for multiplying each row of a matrix by a vector, elementwise? i.e. if I had a matrix: [1,2,3, 4,5,6] and a vector: [2,4,6] the desired result would be a second matrix: [2,8,18, 8,15,36] I'm sure I can do this as a…
Canadian_Marine
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Elementwise subtraction of tensor values in one list

I have a list tensor_list containing tensors in the form of matrices. Some of the matrices have a different shape (e.g. torch.Size([512, 784]) and torch.Size([10, 512])). I want to subtract each element from the element of the successor and store…
Alice
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a 2d numpy array element-wise raised to the power of another 2d array

I need to raise a large 2d numpy array element-wise to the power of another 2d array with the same dimensions. I tried to use numba to improve the speed. Is there an efficient implementation using numpy built-in functions instead of numba? import…
Jayyu
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How to find max values from multiple list and the corresponding list it came from

So I have n arrays which I want to do a element-wise comparisent and find the max value with python. A good solution I found here is: np.maximum.reduce([a,b,c]). But I would like to have another list with tuples corresponding to the max value and…
hero
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Removing DC component for matrix in chuncks in octave

I'm new to octave and if this as been asked and answered then I'm sorry but I have no idea what the phrase is for what I'm looking for. I trying to remove the DC component from a large matrix, but in chunks as I need to do calculations on each…
Robert
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Error using Eigen: Perform element-wise multiplication between a vector and matrix

I am trying to perform an element-wise multiplication of a row vector with matrix. In MATLAB this would be simply done by the "dot" operator or: deriv = 1i * k .* fk; where k is row vector and fk is a matrix. Now in C++ I have this code: static…
Jamie
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vectorized way to multiply and add specific axes in numpy array (convolutional layer backprop)

I was wondering how it would be possible to vectorize the following quadruple for-loops (this is t do with backprop in a convolutional layer). W = np.ones((2, 2, 3, 8)) # just a toy example dW = np.zeros(W.shape) dZ = np.ones((10, 4, 4, 8))*2 # get…
jackewiebohne
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Numpy - Calculate element wise mean for a 1D array

I found multible questions with similar titles but they didn't match with my case. I have a np.array with offset values and I want the mean value for index from all previous values. My first approach was with a for loop, but with huge arrays it is…
Tom Müller
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