2
votes
3answers
66 views

How to get an element of a list , which is computed out of substituted variables?

What is the best way to get the element of a list, which is computed out of substituded variables? For example one wants to get the first element of the first row of ...
3
votes
6answers
162 views

Change last column of a matrix

Given a (rectangular) matrix of integers, i.e. RandomInteger[4, {10, 3}] I want to apply the following rules only to the last column ...
1
vote
1answer
106 views

Matrix/tensor addition behaving funny under replacement?

I have two matrices I want to add, and one of the matrices is a tensor product of two vectors. I've used a SetDelayed to define the summed matrix, because I want to evaluate it for different values of ...
2
votes
2answers
149 views

Matrix exponential via Cayley-Hamilton Theorem

I'm attempting to calculate the exponential of a matrix via Cayley-Hamilton theorem. (Following the "concrete example" from http://en.wikipedia.org/wiki/Cayley%E2%80%93Hamilton_theorem) I am having ...
1
vote
1answer
107 views

Matrix substitution

I'm newbie in Mathematica and would like to ask one simple question. Let's say I have matrix with some elements == -1 ...
0
votes
2answers
122 views

Replace matrix with conditions

I want to replace the values of 1. in slot under the condition that the year and month in basevalue and ...
1
vote
3answers
173 views

Conditional Check on Matrix

Suppose I have the following matrix (i,j): ...
0
votes
0answers
81 views

Back Linear Substitution

I have an equation set Ax=b and A(n*m),n<m . To lower down the dimension, I express some vars by other vars, which gives ...
2
votes
2answers
372 views

Mass Symbolic Manipulation with Subscripts? (from plaintext Input)

The simplest example of the change being sought is a greek letter, typed in as plaintext nu, and its may be replaced by the symbol, ν: expr = 3nu*kx*ky+ ...
7
votes
4answers
193 views

Generating all matrices with 1 (possibly) replaced by -1

I have a matrix $M$, whose dimension I am unsure of, which has only $\lbrace0,1\rbrace$ entries. I would like to generate all the possible matrices that result from changing (some subset) of the $1$'s ...