Questions tagged [matrix]

A matrix is a collection of numbers arranged into a fixed number of rows and columns.

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1answer
60 views

tensorflow pseudo inverse doesn't work for complex matrices!

The Tensorflow documentation here says that: tf.linalg.pinv is ''analogous to numpy.linalg.pinv. It differs only in default value of rcond''. However, tf.linalg.pinv requires the matrix to ...
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1answer
15 views

Recommender system that matches similar customers with similar highly rated products?

I have a dataset of 1,000 customers that bought 20 distinct phones and rated them 1-5. I have several demographic attributes for these customers (gender, age). My website offers 100 distinct devices, ...
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0answers
22 views

Scipy Sparse vstack memory error

I have a bunch of scipy matrices (of the same #columns) loaded from disk. I want to combine them into one scipy sparse matrix. I am using scipy sparse vstack method. I am able to load the ...
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0answers
16 views

Correlation between numeric variables of different meaning

I have a data set containing information about buildings, such as the area code, the neighborhood code, the number of floors, the year in which the house was built and the year in which restorations ...
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11 views

Question regarding: Vectorization Math of Backpropagation in a Neural Network

Formula: These are the formula I use for backpropagation from Brilliant: Question: If we consider a Neural Network with the structure (3,2): And we would start calculating the derivative (for 1 ...
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1answer
32 views

List of Correlations to Correlation Matrix [closed]

I am using python to do some data analysis and I need to represent the following table as a correlation matrix. The correlation value is a value between -1 and 1. ...
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1answer
77 views

Normalize / Standardize in a Random Forest?

If I have a matrix of co-occurring words in conversations of different lengths, is it appropriate to standardize / normalize the data prior to training? My matrix is set up as follows: one row per ...
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0answers
21 views

Matrix multiplication doesn't work - no output

I am having problem in the Matrix multiplication of my Python neural network. Being still a High schooler, I know next to nothing about MM except a couple of tutorials. My Neural network was working ...
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0answers
13 views

Binary Matrix Factorization: Regularizer to encourage 1-0 matrices

I have the following problem: Given a (user, access rights) binary matrix, I need to find the best (user, role) x (role, access right) binary matrices to reconstruct the original matrix. The current ...
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0answers
18 views

Linear Regression Error in feature matrix step

I'm trying to code the design function used in linear regression using numpy and I get this error: Traceback (most recent call last): File "C:\Users\visha\AppData\Local\Continuum\anaconda3\lib\...
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0answers
23 views

One hot encoding of continuous floats using keras backend

I am trying to convert a vector of floats into a matrix similar to one hot encoding, but I want this to happen in non-discrete space to retain gradients. Therefore I am only able to use keras backend ...
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2answers
240 views

How do I generate a laplacian matrix for a graph dataset?

If I have a dataset in a csv that looks like the one shown below. How do I convert this into a laplacian matrix using Python?
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2answers
40 views

Removing # from header

I have a $(418,2)$ matrix and I want to convert it to csv. so I write: np.savetxt('titanic1.csv', Sol, fmt='%.2f', delimiter=",",header="PassengerId,Survived") ...
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81 views

Transformation of matrix with missing values for hierarchical clustering

Comparing different variables, I got a matrix with lots of missing values. How do I have to transform the matrix below for hierarchical clustering? What I have already tried: ...
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1answer
1k views

Calculating cosine similarity between 3D arrays using Python

I have two matrices with multiple columns and three rows each. I calculated the cosine similarity (sklearn) but it gives the result as a matrix. How can I obtain one single value? The matrices are the ...
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2answers
55 views

Is there a difference between np.matrix(np.array([0,0])) and np.matrix([0,0])?

I was reading this code, for implemnting linear regression from scratch: ...
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0answers
86 views

Issue in computing matrix inverse

I need to compute inverse of a matrix that has very small values of the range of 10^-9. When I use numpy.linalg.inv it gives all entries of the inverse matrix as 0. I checked in the original matrix ...
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0answers
18 views

Is this an incorrect way of back-propagating error with matrices?

I was watching a public available video from Stanford (https://youtu.be/d14TUNcbn1k?t=2720) on the mathematics behind back propagation. They proposed a graph: that was then used as an example of back ...
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1answer
268 views

Computation of kernel matrix using radial basis kernel in svm

I want to compute a kernel matrix using RBF on my own. The training data is multidimensional. My query is whether we will apply $$e^{-\gamma(x-y)^2}$$ for each dimension and then sum the values across ...
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40 views

How does on test regression for a subspace or matrix factorization?

I've recently been reading a lot of papers and watching a lot of videos on both subspace learning, and matrix factorization. One thing is particularly eluding me though - how does any of this get ...
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1answer
43 views

Having difficult interpreting the eigenvectors for a simple 3x2 matrix

I calculated the eigenvectors and eigenvalues from a covariance matrix given a data matrix of 3 columns and 2 rows. I am trying to interpret results but I can't understand on how to interpret them. ...
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1answer
853 views

Python memory error: compute inverse of large sized matrix

I have a big matrix of size 200000 x 200000. I need to compute its inverse. But it gives out of memory error on using numpy.linalg.inv. Is there any way to compute the inverse of a large sized matrix.
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1answer
33 views

How do I find output size of a network?

The input to a convolutional layer of a neural network is an image of size $128\times 128\times 3.$ $ 40$ convolutional filters of size $5\times 5$ are applied to it. Would you get an output? If no ...
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1answer
70 views

Faster 3D Matrix Operation - Python

I am working with 3D matrix in Python, for example, given matrix like this with size of 2x3x4: ...
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1answer
157 views

How are weights calculated in a feed-forward neural network before they are summed up with bias?

I have read a lot of papers and watched different videos, it seems like they explain how they are summed up with bias before entering the activation function. What I am trying to understand is the ...
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1answer
166 views

how exp(-z) is working in a sigmoid function in neural networks while z is a matrix?

function g = sigmoid(z) %SIGMOID Compute sigmoid function J = SIGMOID(z) computes the sigmoid of z.% g = 1.0 ./ (1.0 + exp(-z)); end i'm going through andrew ng coursera course i have a doubt ...
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1answer
29 views

Is this matrix correctly built?

I was reading an article called "Ensemble learning in recommender systems: combining multiple user interactions for ranking personalization" where they explain a method they use called "BPR ...
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1answer
103 views

How can I create convolutions or linear layers that operate on vectors rather than scalars in pytorch?

Consider an nn.Linear(2,3) layer transform like the one below. It uses a 2x3 matrix of scalar weights to create a weighted sum for each scalar element in the ...
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2answers
327 views

How can I perform backpropagation directly in matrix form?

I had made a neural network library a few months ago, and I wasn't too familiar with matrices. So, instead of performing matrix dot products (between weights and inputs, then adding a bias matrix), I ...
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2answers
37k views

Normalize matrix in Python numpy

I've an array like this: ...
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0answers
134 views

Dataset containing spatial and temporal features (built on a CNN model)

A dataset contains spatial and temporal features. It contains the time series data (2 min intervals) of the sections of a map. It is 320*480 (320 map sections and 480-time intervals). Each row ...
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1answer
491 views

How to correctly pass Word2Vec vectors as input to an LSTM

I am trying to build a text classifier using lstm which, in its first layer, has weights get by a Word2Vecmodel. In order to ...