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From: Doug Schwarz on 7 Apr 2010 16:04
Matt Fig wrote:
> P = bsxfun(@times,M,V)

Be careful: Since V was specified as a column vector the answer should be

P = bsxfun(@times,M,V.');

Something like

P = bsxfun(@times,M,V(:).');

is more general if the orientation of V is not known.

--
Doug Schwarz
dmschwarz&ieee,org
Make obvious changes to get real email address.
From: Matt Fig on 7 Apr 2010 16:15
But Doug, by the example given:


M = magic(2)*pi;
V = [sqrt(2);sqrt(3)];

% Juliette's technique:
P(:,1)=M(:,1).*V;
P(:,2)=M(:,2).*V

% BSXFUN
P2 = bsxfun(@times,M,V)


>>isequal(P,P2)
ans =
1
From: Juliette Salexa on 7 Apr 2010 16:37
Matt is right,
the transpose would multiply the rows rather than the columns.


I did check the help: http://www.mathworks.com/access/helpdesk/help/techdoc/ref/bsxfun.html

and couldn't find any clues as to why it's called bsxfun

Juliette
From: Matt Fig on 7 Apr 2010 16:40
Look at the help from the MATLAB command window. Notice the first line.

>> help bsxfun
BSXFUN Binary Singleton Expansion Function
C = BSXFUN(FUNC,A,B) Apply an element-by-element binary operation to
arrays A and B, with singleton expansion enabled. FUNC is a
function handle. FUNC can either be a function handle for an
M-function, or one of the following built-in functions:

........ etc., etc., ......
From: Steven Lord on 7 Apr 2010 16:50

"Juliette Salexa" <juliette.physicist(a)gmail.com> wrote in message
news:hpiqdg$8el$1(a)fred.mathworks.com...
> Matt is right,
> the transpose would multiply the rows rather than the columns.
>
>
> I did check the help:
> http://www.mathworks.com/access/helpdesk/help/techdoc/ref/bsxfun.html
>
> and couldn't find any clues as to why it's called bsxfun

This is one case where the function help text has a bit more information
than the function's documentation page. HELP BSXFUN says:

> help bsxfun
BSXFUN Binary Singleton Expansion Function
*snip*

I suppose you could say that the first line of the help should be:

BSXFUN Binary Singleton eXpansion FUNction

but I think it's close enough. Choosing names for new functions and new
functionality can be (much) harder at times than people think, trust me.

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ


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