The Death of Reading
Reading university physics department is to stop taking new students from next year, with a view to closing in 2010.
Saturday, September 30, 2006
Labels:
depressing
Thursday, September 28, 2006
Hermite polynomials in MATLAB
Have spent the afternoon ascertaining that
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
Have spent the afternoon ascertaining that
- MATLAB has no built in function to generate Hermite polynomials, and
- Various programmes on the InterWeb that purport to generate them do NOTHING of the sort, yet
- This does not stop Randoms posting them, so
- I have been forced to write my own.
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
Labels:
maths,
public service
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:
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
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:
A lot of people are very cross. So cross they have written to The Torygraph:
Modern life leads to more depression among childrenwhere 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...Adjective city:The words are as ugly as they are meaningless.
complex socio-cultural problem
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.
Subscribe to:
Posts (Atom)