Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Text data save
Replies: 7   Last Post: Oct 14, 2013 5:09 PM

 Messages: [ Previous | Next ]
 dpb Posts: 9,850 Registered: 6/7/07
Re: Text data save
Posted: Sep 9, 2013 7:40 PM

On 9/9/2013 6:24 PM, Debela wrote:

...[Top posting repaired -- don't; hard follow conversation makes]...

> "Steven_Lord" <slord@mathworks.com> wrote in message
> <kv03oc\$t8m\$1@newscl01ah.mathworks.com>...

>>
>>
>> "Debela " <bisaye@gmail.com> wrote in message
>> news:kv01sd\$qkf\$1@newscl01ah.mathworks.com...

>> > Hi all,
>> > I have a problem on analysis of big matrix data, it is 1600x3000.

>> What I > wanted to do is to select the maximum value of each raw and
>> save it. For > example, x=data(3,:); max(x); can give me the maximum
>> value of 3rd raw > out of 1600 but I want for all of them I tried a
>> for loop and it is not > really successful. Any help would be
>> appreciated.

>> > Debela
>>
>> Use the DIM input to the MAX function.
>>
>> x = magic(7);
>> maxDownColumns = max(x, [], 1)
>> maxAcrossRows = max(x, [], 2)

...

> Thanks a lot. I still have some issues though. I wanted to find the
> maximum and corresponding index (Which I can find now), but I want also
> another value. For example if my maximum value is x, I want to find the
> index of 0.8 *x and 0.002*x. The closest I came across is I multiplied
> the maximum values by 0.8 and 0.002. Is there anyway I can find
> something out of it. I have done in the past using for loop, the data
> size was smaller though. Thanks.

Same idea, just

ix=find(x==0.8*xmax); % for example

NB: the above is subject to floating point roundoff; use

ix=find(abs(x-0.8*xmax)<1E-6); % or similar w/ a suitable error

--

Date Subject Author
8/20/13 Bizuayehu Mohammed
8/20/13 Steven Lord
9/9/13 Bizuayehu Mohammed
9/9/13 dpb
10/14/13 Bizuayehu Mohammed
10/14/13 dpb
10/14/13 Bizuayehu Mohammed
10/14/13 dpb