Python College

This is the definition of a covariance matrix. http://en.wikipedia.org/wiki/Covariance_matrix#Defin… Read more How Is Covariance Implemented Internally In Numpy?

I have a large sparse matrix in python, and would like to perform many elementary row operations on… Read more Fast Row Operations With Python Sparse Matrices

I'm implementing Strassen's Matrix Multiplication using python. In divide step, we divide a… Read more How To Split A Matrix Into 4 Blocks Using Numpy?

I am trying to create a 2d matrix so that each cell contains a list of strings. Matrix dimensions a… Read more 2d Array Of Lists In Python

How to return a set of rows of a NumPy Matrix that would match a given condition? This is a Numpy M… Read more How To Get A Subset Of Rows From A Numpy Matrix Based On A Condition?

I am very new to Python. I have a list of tuples, where I created bigrams. This question is pretty … Read more Create A Frequency Matrix For Bigrams From A List Of Tuples, Using Numpy Or Pandas

I've made a function to search horizontally for a word in a matrix full of letters. Now I'm… Read more How To Find Words In A Matrix - Python

I have a matrix [['1', '2'], ['3', '4']] which I want to convert to… Read more How To Convert A Matrix Of Strings Into A Matrix Of Integers Using Comprehensions

I am profiling a numpy dot product call. numpy.dot(pseudo,pseudo) pseudo is a numpy array of cust… Read more Reasons Of Slowness In Numpy.dot() Function And How To Mitigate Them If Custom Classes Are Used?

I have two distance matrices, each 232*232 where the column and row labels are identical. So this w… Read more Understanding Output From Kmeans Clustering In Python

In scipy, when I multiply a slice of a sparse matrix with an array containing only zeros, the resul… Read more Multiply Slice Of Scipy Sparse Matrix Without Changing Sparsity

In Python I need to find the pairwise correlation between all features in a matrix A and all featur… Read more Efficient Pairwise Correlation For Two Matrices Of Features

Let's say I have the lists [[1,2],[3,4]] and [[5,6],[7,8]] I expect [[6, 8], … Read more How Do I Combine Indexes Of Two Lists?

I understand that eigenvectors are only defined up to a multiplicative constant. As far as I see al… Read more Eigenanalysis Of Complex Hermitian Matrix: Different Phase Angles For Eig And Eigh

I know how to solve A.X = B by least squares using Python: Example: A=[[1,1,1,1],[1,1,1,1],[1,1,1,1… Read more How To Use Least Squares With Weight Matrix?

I have an adjacency matrix of a bipartite graph (of 1's and 0's) and bi-clusters (array of … Read more How To Change Colour Of Certain Elements Of A Matrix In Matplotlib Matshow?

I want to compute the second eigenvalue of a Laplacian matrix to check if the corresponding graph i… Read more Sympy Could Not Compute The Eigenvalues Of This Matrix

I just started using Python and I just came across the following problem: Imagine I have the follow… Read more How To Create A Frequency Matrix?

I have a tensor U composed of n matrices of dimension (d,k) and a matrix V of dimension (k,n). I w… Read more Tensor Multiplication With Numpy Tensordot

I wonder what could be the easiest way to create a bi-dimensional array, that has for each row the … Read more Simpler Way To Create A Matrix/list Of Indices?