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# Darren Rowland

388 total contributions since 2009

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Responded

Re: Fall 2012 MATLAB Contest: October 31 - November 7
Helen Chen" <helen.chen@mathworks.com> wrote in message The new file has for j = i+i:nLines instead of for j = i+1:nLines ...

4 years ago | 7715 views

Posted

Replacing section in a matrix
Here is the basic idea A = zeros(180,360); A(100:127,100:163) = 1; % index into the matrix imagesc(A) You can also do the fo...

5 years ago | 6584 views

Responded

Re: deleting observations in linear regression
Sounds like the PRESS method (predicted residual sum of squares). I can't seem to find a decent reference, but there is a file o...

5 years ago | 2576 views

Responded

Re: check if vector is subset of another
The file findsubmat by Matt Fig should do the job http://www.mathworks.com/matlabcentral/fileexchange/23998-findsubmat Hth Darr...

5 years ago | 15581 views

Responded

Re: Spring 2011 MATLAB Contest, April 13 - April 20
Congratulations Nick. Superb effort to knock so much off the score on the final day. Thanks to the contest team. I only watched...

5 years ago | 14163 views

Responded

Re: Spring 2011 MATLAB Contest, April 13 - April 20
The scoring system is interesting in that the length of bogus words does not factor in. So it's advantageous to make long invali...

5 years ago | 14163 views

Responded

Re: Non-linear 3rd Order multiple regression
Hi James, I recommend John D'Errico's polyfitn http://www.mathworks.com/matlabcentral/fileexchange/10065-polyfitn Hth Darren

6 years ago | 3225 views

Responded

Re: Secant Method
It will probably work if you replace this f=inline('(4/3)+2*sin(pi*x/3)-x') with a function handle, i.e. f=@(x) (4/3)+2*sin(p...

6 years ago | 3698 views

Posted

Regula Falsi Method
You haven't shown your calling syntax, which is what the error is related to. I assume that it is because you are not correctly ...

6 years ago | 4659 views

Responded

Re: Making a program of perfect numbers
This FEX file should do the trick http://www.mathworks.com/matlabcentral/fileexchange/24500-divisorn Darren

6 years ago | 6858 views

Responded

Re: Making a program of perfect numbers
Take a look at the output from factor ans = So you need to compute the divisors, not the factors. Hth Darren

6 years ago | 6858 views

Responded

Re: plotting polynomials
Hi Yazid, meshgrid and mesh are used for 3D plots. From the question it seems that you require only 2D. To plot y(x) over the ...

6 years ago | 4268 views

Responded

Re: How to extract unique rows from a matrix
Yeah, it's quite a fast approach too, should be adequate for the OP.

6 years ago | 2912 views

Responded

Re: How to extract unique rows from a matrix
Hi James, The output from unique isn't exactly what you want. Try this instead. [b,m,n] = unique(A,'rows'); h = histc(n,1:size(...

6 years ago | 2912 views

Responded

Re: need help speeding up for loop currently using "find"
Is D sorted?

6 years ago | 1548 views

Responded

Re: two dimensional interpoltaion
On a similar vein, there is a great utility on the File Exchange for this kind of thing, gridfit by John D'Errico http://www.ma...

6 years ago | 2889 views

Responded

Re: Griddata command - Triangle-based cubic interpolation
Within the griddata.m file (view it by typing "edit griddata" at the command prompt) there is the following information. %TRIAN...

6 years ago | 2762 views

Responded

Re: All possible combinations of matrices
You haven't really described the problem well enough for anyone to be able to help you. Given your example board 101 000 111 11...

6 years ago | 3388 views

Responded

Re: New layout
I like the new approach but there are just a couple of areas which need improvement. I agree with Jan, the colours chosen for t...

6 years ago | 1456 views

Responded

Re: Newton Raphson
Can you post what you have started with, so we know where you are stuck. Thanks Darren

6 years ago | 5341 views

Responded

Re: passenger waiting time at a bus stop when bus has limited carrying capacity of passengers
Kamrul, Try this code. I put the separate parts into functions so the biggest change is that there is now a loop which maintain...

6 years ago | 5584 views

Responded

Re: passenger waiting time at a bus stop when bus has limited carrying capacity of passengers
Hopefully you have already made a start but if not this may help. I suggest highlighting segments and executing with F9 to see w...

6 years ago | 5584 views

Responded

Re: Matlab 3-d Walk problem
There are a few ways you might do it but here is one which - I think - does what you want. function avgDispK = randWalk3D numTr...

6 years ago | 11520 views

Responded

Re: Matlab 3-d Walk problem
No problem. Here is an alternative method which forms the random steps, then uses cumsum to get the resultant positions N = 10;...

6 years ago | 11520 views

Responded

Re: Matlab 3-d Walk problem
Something like this perhaps, where the positions visited are recorded, rather than the steps. position = zeros(3,N+1); for k = ...

6 years ago | 11520 views

Posted

REMOVE DUPLICATE ENTRIES WITHOUT SORTING

6 years ago | 11536 views

Responded

Re: Plot Going Out of Axes Limits
Hi Jahanzeb, Could you please post some code to create this (or a similar) figure, then describe what actions you take to produ...

6 years ago | 2563 views

Submitted

diffxy
Second-order accurate numerical differentiation (N-dimensional)

Responded

Re: Genetic Algorithm Display Problem
There doesn't seem to be any obvious problems with your options, but unfortunately I don't have the global opt toolbox to check ...

6 years ago | 1309 views

Responded

Re: Genetic Algorithm Display Problem
Can you please post the options you have set, as well as the function call syntax. This will help to diagnose the problem. You ...

6 years ago | 1309 views