## Saturday, September 30, 2006

Reading university physics department is to stop taking new students from next year, with a view to closing in 2010.

## Thursday, September 28, 2006

Hermite polynomials in MATLAB

Have spent the afternoon ascertaining that
1. MATLAB has no built in function to generate Hermite polynomials, and
2. Various programmes on the InterWeb that purport to generate them do NOTHING of the sort, yet
3. This does not stop Randoms posting them, so
4. I have been forced to write my own.
If anyone finds it useful, please use the code (at your own risk etc). To normalise on the interval [+infinity..-infinity] with respect to the weighing function exp(-alpha x^2) just multiply by\sqrt{\frac{alpha}{\sqrt{\pi}2^n n!}}

The parameter k determines the largest hermite polynomial calculated (k-1)
The coefficients in x^0 x^1 x^3 are along the columns of the output matrix, and the
nth row is the (n-1)th polynomial. Try it out!

Code (Tested MATLAB 6.1)

% Function herm
% Generates the coefficients for a hemite polynomial of order 'k' from the recursion relation
% H_(n+1) = 2xH_n - 2nH_(n-1)

% Function output is a matrix
function A = herm(k)
% Generate a k+1 by k+1 matrix
A=zeros(k+1);
if k == 0; %only generate H_0
A(1,1)=1 ; % Defines H_0=1

elseif k == 1; % only generate H_1
A(1,1)=1 ; % Defines H_0=1
A(2,1)=0; % Defines H_1=2x
A(2,2)=2; % ditto

else

A(1,1)=1 ; % Defines H_0=1
A(2,1)=0; % Defines H_1=2x
A(2,2)=2; % ditto

for i=2:k
A(i+1,1)=-2*(i-1)*A(i-1,1) % -2nH_(n-1)

for j=2:k+1
A(i+1,j)=2*A(i,j-1) -2*(i-1)*A(i-1,j) % 2xH_n - 2nH_(n-1)
end
end

end

## Thursday, September 14, 2006

Won't somebody think of the children?

A lot of people are very cross. So cross they have written to The Torygraph:
Modern life leads to more depression among children
where they bemoan:
The
"professionals and academics from a range of backgrounds" think parents aren't raising their children is the approved manner.
I hope they are better at child raising than they are at letter writing: the fragment
...regular interaction with the real-life significant adults in their lives...
should not be thought, let alone written.
fast-moving hyper-competitive culture....overly academic test-driven primary curriculum...
complex socio-cultural problem
Adjective city:The words are as ugly as they are meaningless.
One of the signatories, Professor Susan Greenfield, stated on Newsnight that there was a danger of
"Icons replacing Ideas"
I don't know what this means. I suspect she doesn't, either. One of my correspondents writes:
This meaningless soundbite leads me to wonder not at the declining standards in our children but the declining standards in our experts. Children have a refreshing habit of ignoring people who talk crap as adults do we loose this wonderful gift?
Quite so.