Answered
Surface area from a z-matrix
OK, well how about splitting each quadrilateral into two triangles, and just summing up the areas? I'm sorry there's no way I ca...

11 years ago | 0

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Answered
Argmin with several minimums
It doesn't feel very satisfactory, but this will do the trick I = find(A == min(A))

11 years ago | 0

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Projecting Points to a new Basis
I'm not sure what your question is asking because you're missing a symbol off your question. But I think you mean if n is not eq...

11 years ago | 0

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How can I use "symbfact" to speed up several consecutive Cholesky factorizations?
You can't (unless something has changed recently). When I had to do this, I ended up working with the C code in CSparse directly...

11 years ago | 0

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Answered
Simple solution to a simple problem
Try 1./(1 + 9*x.^2) i.e. a '.' before the division

11 years ago | 0

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Piecewise Cubic Hermite Interpolating Polynomial (PCHIP)
It works perfectly x = [5.8808 6.5137 7.1828 7.8953]; y = [31.2472 33.9977 36.7661 39.3567]; pp = pchip(x...

11 years ago | 0

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Answered
Sparse and nonspare QR
Sorry to take a while, busy week. Neither are wrong. You'll notice that the only difference in the outputs is that the sparse ve...

11 years ago | 0

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Answered
Sparse and nonspare QR
On my system they match (up to the signs of the rows, as you'd expect). m = 20; n = 10; X = sprand(m,n,0.3); Rs...

11 years ago | 0

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How to calculate expm of a badly scaled matrix?
You might this Cleve's corner instructive <http://blogs.mathworks.com/cleve/2012/07/23/a-balancing-act-for-the-matrix-exponenti...

11 years ago | 0

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Answered
MATLAB Project for Chemistry
How about simulating the Belousov-Zhabotinsky reaction in 2 dimensions? Start by watching some YouTube videos and work from ther...

11 years ago | 0

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How to run multiple different scripts in parallel ?
One way to do it matlabpool open local 4 spmd switch labindex case 1 script1 ...

11 years ago | 0

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Row by column multiplication
There is a built in way to do it quickly if you use sparse multiplication. Essentially, you construct the block diagonal matrix ...

11 years ago | 0

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How to calculate eigen values and eigen vectors of a square matrix without using eig() function?
_"Please tell me algoritm for this."_ * Power Method * Inverse/Shifted Inverse Power Method * QR Algorithm * Jacobi Algori...

11 years ago | 0

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Proper implementation and use of fmincon
I presume [1 2 3 4] and [6 7 8] are sets of possible values for x1 and x2. If your problem is only small, then you can use brute...

12 years ago | 0

Answered
Find Joint Angle for Animation
You are taking the dot products of the wrong vectors! You need to take the vectors emanating from M2. The following should do th...

12 years ago | 0

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Answered
Performing Gauss Elimination with MatLab
The function you want is LU [L, U] = lu(K); The upper triangular matrix resulting from Gaussian elimination with partial...

12 years ago | 2

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Attempted to access Pe(7); index must be a positive integer or logical.
Your problem is that |q| and hence |m| are floating point numbers, not integers. in this case the problem is that m = 0.6 /...

12 years ago | 0

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Solving an implicit function, fsolve vs. fzero
How about doing a fixed number of Newton steps for each problem? (not necessarily doing a convergence check) For example: ...

12 years ago | 0

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How do I find common volume of spheres?
Here's how I'd do it (if I was in a hurry). First pretend all the spheres are cubes, and find their intersection. inx = [...

12 years ago | 0

Answered
Problem using 'deal' for objective and gradient in comb. with 'DerivativeCheck'
An internal routine (in this case |finDiffEvalAndChkErr|) is calling your routine with only one output. For a regular function t...

12 years ago | 0

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Answered
Minimizing the values in an underdetermined Matrix - minimize with constraints
*edit*: fixed mistake in call to |linprog| To perform L1 minimisation, you'll need access to an LP solver. If you have the op...

12 years ago | 0

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Answered
How to change selected data which would give me the line of best fit (R squared close to 1)?
For the first part x(logical(imag(x))) = nan; For the second, your data points are all over the show. Any two will fit a s...

12 years ago | 0

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Answered
Initializing vs growing a structure
Let's say you wanted to create a 100x1 struct array with a field |A| that you know will store a 3x3 matrix struct('A', repm...

12 years ago | 4

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Minimizing the values in an underdetermined Matrix - minimize with constraints
Assuming you want a minimal Euclidean norm solution, there's no built-in function, but I can offer you a two-line solution: ...

12 years ago | 0

Answered
How to maximize this function: x1^2+x2^2+...+xn^2 ?
I assume you mean minimise rather than maximise, because unless you have |n| independent constraints, your problem is unbounded....

12 years ago | 0

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Can linprog give an integer value of x's?
No there isn't. Integer linear programming is a different beast. Perhaps this one from the file exchange might help: <http://...

12 years ago | 0

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Answered
How to output matlab ode dependent variable at same time step as T and Y?
By far the best way is to compute your dependent variable _afterwards_ with the |y| matrix that was computed by the ODE solver. ...

12 years ago | 1

12 years ago | 0

Answered
how to construct an affinity matrix?
This might be helpful <http://www.mathworks.com/matlabcentral/fileexchange/26354-spectral-clustering-algorithms>

12 years ago | 0

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12 years ago | 0