taylor series and vector/matrix etc

[Vegan]

I created a exp function for a matrix, had to first create a pow
function then exp could call that
no problem

so I used a taylor expansion to do the work

so it got me thinking, do vectors and matrices all good with taylor
expansions etc

[Rob Beezer]

You can form any polynomial of a square matrix, since powers make sense, and
then scalar multiples and addition are the most basic operations. This is
Subsection EE.PM.

With vectors this would not be so natural, but it is sometimes advantageous to
multiply a polynomial of a square matrix times a vector. See the proof of
Theorem EMHE.

Rob

[Vegan]

Thanks, I was considering something along the line of
exp(A) where A is a matrix etc


template <typename T> matrix<T> pow(matrix<T> &radix, int signficand) {
    matrix<T> product = radix;
    for (int i = 1; i < significand; i++)  // Brutal computations
        product = product * radix;
    return product;
}

template <typename T> matrix<T> exp(matrix<T> &exponent) {
    matrix<T> sum = 0; // Maclaurin series expansions
    for (int k = 0; k < 6; k++) { // 6 terms should be enough
        sum = sum + (pow(exponent, k) / factorial(k)); // Power series
    }
    return sum;
}