matrix assignment from a matrix A to a matrix B using conditional statements based on a third matrix C 
by 007ELmO in Programming Languages 

I have two questions if you can kindly respond: Q1) I have a
matrix choice , where each person is making 4 of any possible
choices, denoted as 1, 2, 3 and 4. I have three matrixes
A1 , A2 , A3 with income information
for each person and each time period. Say I have n people and t time
periods so A1 , A2 ,


Is there any builtin type of matrix in CUDA for matrix and matrixvector operation? 
by pulkizine in Programming Languages 

I want to implement some matrix–vector math. There are vector
types like: float2 , int2 , but I cannot find any
builtin type matrix in CUDA. Is there a library that suitable
for such operations?

Based on a matrix A, generate a matrix B with all possible multiplications of the columns of Matrix A 
by riahc3 in Programming Languages 

Say I have a matrix with 3 columns: c1 ,
c2 ,c3 , and I want to create a new matrix in which
each column is any possible product of two of the columns of this matrix.
So, if I had a matrix with d columns, I would like to create a
new matrix with d+d(d1)/2+d columns. For example, consider the matrix with
3 columns c1 , c2


Replace matrix values in a matrix with mean values extracted from a smaler matrix in matlab 
by Wesley D. Radcliffe in Programming Languages 

Lets say I have an 10 x 10 matrix. What I do then is iterate throug the
whole matrix with an 3x3 matrix (except the edges to make it easier), and
from this 3x3 matrix I get the mean/average value of this 3x3 space. What I
then want to do is to replace the orignal matrix values, with those new
mean/average values. can someone please explaine to me how I can do that?
Some code examples would be a

Accessing a matrix element by matrix[(a, b), c] instead of matrix[a, b, c] 
by seigel in Programming Languages 

I want to achieve the following: Have a AxBxC matrix (where
A,B,C are integers). Access that matrix not as matrix[a, b,
c] but as matrix[(a, b), c], this is, I have two variables, var1 =
(x, y) and var2 = z and want access my matrix as matrix[var1,
var2]. How can this be done? I am using numpy matrix, if it makes
any difference. I know

How to store Sparse matrix for a matrixvector multiply when some boundary condition values are known? 
by dougbeal in Programming Languages 

I have a sparse matrix that represents a 3D rectangular space. Along
some of the boundaries, I know what the value is going to be (it's a
constant). The other boundaries may be reflective, differential, etc.
Should I just set the problem up as if all the boundaries were
say, differential, and then go back and set the nodes in the solution
vector b to be the constants? T

find row wise index of specific elements in a matrix and populate another matrix 
by keird in Development Tools & Services 

I have a matrix of 10 stock returns for 100 days ( 100 rows and 10
columns ) . I am applying the following operations on it. I
have used loops which takes a very long time on a bigger data set. I'm sure
this can be simplified using array operations. 1) select the
top 3 and bottom 3 values in each row and store the index of the values in
a "select" matrix (also a 100x10

Is there a way to get a parametric solution to matrix using matrix solver from some lin. algebra java library? 
by icode.cs in Java 

All the matrix solvers I've come across require the matrices to be
square and invertible, but what about matrices that are not square and have
multiple solutions...how would I go about finding a parametric form of this
using java?

Java. Writing a matrix in a file using column information. ( matrix transposition ) 
by Switzerland in Programming Languages 

I have a file in which a matrix is stored. This file has a
RandomAccessFile type. This matrix is stored by columns. I mean that in an
ith row of this matrix an ith column (of a real matrix) is stored. There
is an example: ith row: 1 2 3 4 (in the file). That means that the
real matrix has an ith column: (1 2 3 4)(is transposed). I
need to save this matrix in a natural way (

Eigen decomposition of a matrix of form W * diag(S) * W' for matrix exponential in MATLAB 
by miceno in Programming Languages 

W is a tall and skinny real valued matrix, and
diag(S) is a diagonal matrix consists of +1 or
1 on the diagonal. I want the eigen decomposition of A
= W * diag(S) * W' where single quote denotes transposition. The
main problem is that A is pretty big. Since A is
symmetric, rank deficient, and I actually

