Statistics
RANK
28
of 239.240
REPUTATION
6.076
CONTRIBUTIONS
0 Questions
2.061 Answers
ANSWER ACCEPTANCE
0.00%
VOTES RECEIVED
1.364
RANK
6.353 of 16.802
REPUTATION
141
AVERAGE RATING
5.00
CONTRIBUTIONS
1 File
DOWNLOADS
3
ALL TIME DOWNLOADS
1319
CONTRIBUTIONS
0 Posts
CONTRIBUTIONS
0 Public Channels
AVERAGE RATING
CONTRIBUTIONS
0 Highlights
AVERAGE NO. OF LIKES
Your submissions received 1 five star rating
Awarded to Roger Stafford on 09 Oct 2019
Publish your first submission
Awarded to Roger Stafford on 09 Oct 2019
Obtain 50 solvers for a problem you have created
Awarded to Roger Stafford on 02 Nov 2018
Contribute at least one answer each month for 24 consecutive months
Awarded to Roger Stafford on 20 Jul 2017
Answer 3 questions that were unanswered for more than 30 days
Awarded to Roger Stafford on 20 Jul 2017
100 of your answers have been accepted
Awarded to Roger Stafford on 20 Jul 2017
Provide your first answer ever to someone else's question
Awarded to Roger Stafford on 20 Jul 2017
Comment on a problem or solution
Awarded to Roger Stafford on 23 Feb 2012
Create a problem
Awarded to Roger Stafford on 02 Feb 2012
Be the first to solve a problem
Awarded to Roger Stafford on 25 Jan 2012
Solve a problem for the first time
Awarded to Roger Stafford on 25 Jan 2012
Content Feed
Corrcoef of two variables of unequal lengths
Mathworks states in their description of corrcoef, "R = corrcoef(X) returns a matrix R of correlation coefficients calculated ...
más de 1 año ago | 0
| accepted
Eigenvectors are not orthogonal for some skew-symmetric matrices, why?
Your matrix A is _"defective"_ , meaning that its eigenvalues are not all distinct. In fact, it has only three distinct eigenva...
casi 3 años ago | 1
| accepted
Sum of highest length of consecutive lowest values from a array.
L = min(A); f = find(diff([false,A==L,false])~=0); h = L*max(f(2:2:end)-f(1:2:end-1)); h is the highest sum of consec...
más de 3 años ago | 0
What condition to use for checking whether at least a single negative element in a array?
Use the 'any' logical function. if any(A.*B<0) If you are dealing with an array, C, of more than one dimension, do this:...
más de 3 años ago | 0
| accepted
How to Make a Matrix Diagonal with Matlab?
Call on Matlab's 'svd' function. Read about it at: https://www.mathworks.com/help/matlab/ref/svd.html or possible you n...
más de 3 años ago | 0
Finding if a vector is a subset
The following should be faster: m = size(a,2); n = size(b,2); for k = 1:n-m+1 s = all(a==b(k:k+m-1)); if s,...
más de 3 años ago | 0
| accepted
How to plot level curves of f(x,y) = 2x^2 + 5y^2. f(x,y) = c for c = 1,2,3,4,5,6
Your "level" curves are all ellipses and can most easily be generated by: t = linspace(0,2*pi); x = sqrt(c/2)*cos(t); ...
más de 3 años ago | 0
how to make a function (named pcc ) that solves the cartesian product of 2 strings A(with n elements) and B(with m elements)?
Assume A and B are row strings. C = [reshape(repmat(A,length(B),1),[],1),repmat(B(:),length(A),1)]; The two-element rows...
más de 3 años ago | 0
how to create function half adder in matlab
If the input bits are numeric scalars or logical values, b1 and b2, then the sum bit, 's', would be: s = b1 xor b2; or e...
más de 3 años ago | 0
| accepted
Using nested loops, write a Matlab program that goes through all elements of a matrix (2D array) and replaces every element that is either a multiple of 5 or 7 with -1.
Your test on a number x from your array can be: if round(x/5)==x/5 | round(x/7)==x/7 (Doing fprintf('-1') just prints ou...
más de 3 años ago | 0
What is the output?
The vector x has only three elements, [0,.3,.6], so the 'for' instruction reads: for n = 4:2 Therefore the loop will not...
más de 3 años ago | 0
Please help me convert equation to matlab code.
N = 100; % <-- Choose some large number s = x; for n = 2*N-1:-2:1 s = x - s*x^2/((n+2)*(n+1)); end (I t...
más de 3 años ago | 0
Why am I getting Inf in my matrix
It is easily possible for two finite nonzero numbers to have a quotient so large that Matlab must give 'inf' as its value. For ...
más de 3 años ago | 1
| accepted
Multiply a column by a number
Let Ar be the name of the array. Ar(:,6) = 4*Ar(:,6); What could be simpler? Since 4 is a scalar, it is automatically a...
más de 3 años ago | 0
how to use nested for loop by grabbing one column and subtracting another column.
Your n value will be 1478, but in z(i,j+1) you have allowed the j+1 index to get as large as 1479 because you have "for j=1:1:n"...
más de 3 años ago | 0
Why does y come out as one number?
The scalar result is caused by the use of matrix division rather than element-by-element division. Replace '/' by './'. Simila...
más de 3 años ago | 0
Lagrange Interpolation code error
The message is caused by your not defining or properly entering the value of vector 'xi'.
más de 3 años ago | 0
Trapezoidal rule to find total work?
I would think your code should be this: work = 0; for k = 2:length(t) work = work + (F(k)+F(k-1))/2*(v(k-1)+v(k))/2...
más de 3 años ago | 0
| accepted
How to do polynomial differentiation
Let P be the usual Matlab row vector of coefficients of a polynomial. Then, (as we all learned in calculus,) the corresponding ...
más de 3 años ago | 1
| accepted
convert two column matrices into one column matrix
In the example you gave do this: C = zeros(9,1); C(1:2:end) = A; C(2:2:end) = B; For a general answer you need to ...
más de 3 años ago | 0
Does 'i' after value stand for 'index', and if so why does it appear as part of the answer?
The 'i' in your result indicates a complex answer. I assume you are familiar with complex numbers. The 'i' represents the squa...
más de 3 años ago | 1
| accepted
Representing base 4 numbers as "random walks"
The Matlab function 'dec2base' can be used to covert integers to character strings involving the characters '0', '1', '2', and '...
más de 3 años ago | 0
How to generate a joint probability matrix from a data matrix
Call the data matrix D. Then the two columns of D(:,2:3) are X and Y. XY = sortrows(D(:,2:3)); F = find( [true,any(XY(1...
más de 3 años ago | 0
How can I write a program that indicates a number if it is integer or not?
If n is your number, then round(n)==n is true if and only if n is an integer
más de 3 años ago | 0
where can i use round function to make the function perfect
I would suggest initially multiplying both 'tendered' and 'price' by 100 and using 'round' on the result: tendered = round(...
más de 3 años ago | 0
| accepted
if a & b
You can't use the "short circuit" forms of logical operations for operands other than scalars. The double symbol '&&' is the sh...
más de 3 años ago | 1
How do I use an matrix of indices to reference values in another matrix without using a loop?
[a,b,c] = size(alltemps); % tempindex must be 1 x b x c savedtemp = reshape(alltemps(reshape(tempindex,1,[])+(0:a:a*(b*c-1...
más de 3 años ago | 0
| accepted
Solving a system of integral equations numerically
@Lewis: I noticed that the integrands in both of your integrals become infinite at the upper limit of integration, and this can ...
más de 3 años ago | 0
Solving a system of integral equations numerically
This is a problem you can solve using Matlab's 'fsolve' function. The fact that your objective function requires two numerical ...
más de 3 años ago | 0
How to plot a circle centered on a line and passing through a point?
There are infinitely many ways a circle can be centered on a line and pass through a given point, except for the case when a lin...
más de 3 años ago | 0
