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differentiable approximation of bandwidth in ksdensity for optimization
I have an optimization loss term ||x* - y||^2 where x* corresponds to a quantile approximated via ksdensity (e.g., x* = ksdensit...

5 months ago | 1 answer | 0

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answer

Question

Most efficient way to vertically concatenate numeric data?
In the profiled output picture below, mergedDataPerRank is a cell array storing 53 double matrices with size (6300, 33). Using v...

5 months ago | 0 answers | 0

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answers

Question

nonlinear spline fit with unknown upper bound of interpolation domain
I want to fit the interpolation values of a spline, but I can not provide a good guess for the upper bound of the interpolation ...

6 months ago | 1 answer | 0

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Question

starting vector (zero vector) equals lower bounds but gets projected to non-zero vector
I created a small example where I created a start vector euqal to the lower bounds, so the start vector respects the bounds, tho...

11 months ago | 2 answers | 0

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scale/normalize parameter vector for optimization
In my optim problem, the parameters naturally vary by several orders of magnitude because they represent interpolation values ...

11 months ago | 3 answers | 0

3

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Question

transform linear inequality constraints into bound constraints for optimization solvers
Suppose there are linear inequality constraints and are the parameters optimized by fmincon, lsqnonlin, or friends. Since lin...

11 months ago | 2 answers | 0

2

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Question

wait for several system calls to finish
I am calling three external programs and can only continue in the matlab program after all programs are finished. Each of them w...

1 year ago | 2 answers | 0

2

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Question

uniform knot vector for splines
Suppose we have uniform interpolation points, e.g x = [1 2 3 4 5 6] The functions for knot generation produce knots of the for...

1 year ago | 1 answer | 0

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Question

express basis spline derivative in terms of interpolation values
x = [1 2 3 4 5]; y = randn(size(x)); f = spapi(5,x,y); fdd = fnder(f, 2); If we evaluate the second derivative at a given po...

1 year ago | 1 answer | 0

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Question

steps to convert spline from B-form to pp-form (fn2fm)
x = [3.0,4.5,6.0,7.5,9.0,12.0,15.0]; y = [0 0.0343653 0.0694232 0.105143 0.141178 0.246013 0.630537]; f_bm = spapi(5, x, y); ...

1 year ago | 1 answer | 0

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Question

spapi: why slvblk instead of backslash operator?
% data x = [3.0,4.5,6.0,7.5,9.0,12.0,15.0]; y = [0 0.0343653 0.0694232 0.105143 0.141178 0.246013 0.630537]; xq = linspace(...

1 year ago | 1 answer | 0

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Question

distribution of interpolation points in spline interpolation
rng("default") n = 10; x = linspace(1,10,n); xi = linspace(min(x), max(x), 1e3); y = rand(length(x)); pp = csape(x,y); % in...

1 year ago | 1 answer | 0

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Question

cubic spline interpolation - mixed boundary conditions possible?
We need two boundary conditions. Is it possible to specify the first and second derivative at the same boundary point? In csap...

1 year ago | 3 answers | 0

3

answers

Question

Interpolation schemes that produce positive second derivatives of the interpolant
Given a set of x-values and y-values. The interpoland to this data should have non-negative second derivatives, allowed to be di...

1 year ago | 5 answers | 0

5

answers

Question

fmincon optimization: is the first order optimality very sensititve to changes in the step tolerance?
I use fmincon interior-point algorithm to fit parameters to a pde. Here are my basic settings: opts = optimoptions('fmincon',...

2 years ago | 1 answer | 1

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Question

parfor chuncks: are loop iterations running in parallel WITHIN a chunck on local machine?
I know that parfor does load-balancing to break the loop iterations into chuncks which are then sent to the workers. Demo exam...

2 years ago | 1 answer | 0

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Question

global optimization in parallel in combination with external pde solver
I use MultiStart from the global optimization toolbox to run lsqnonlin solver for a bunch of start vectors. I want to run the l...

2 years ago | 1 answer | 0

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answer

Question

matlab uitable: split columns into several rows
I construct an uitable from a struct like: % params is a struct T = struct2table(params); fields = fieldnames(params)'; fig ...

2 years ago | 1 answer | 0

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Question

graphical visualization of input parameters collected in a struct/array
My simulation depends on a whole bunch of input parameters that control various features of the simulation. I decided to group...

2 years ago | 2 answers | 0

2

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Question

vectorize expression containing if statement
A = [-5 3 2;2 3 4; 3 5 6; -2 8 9]; %compute product of columns in a vectorized fashion A(:,1).*A(:,2).*A(:,3); %calculate the...

2 years ago | 1 answer | 0

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Question

tall array introduces significant overhead if I call gather() at every iteration in a loop
I want to figure out the spread of the invariants of a symmetric 3x3 matrix using the code below %input nPts = 2; ub = 2.0; ...

2 years ago | 1 answer | 0

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Question

out-of-memory because of large array: tall array as a workaround?
Given a symmetric, positive definite 3x3 matrix (6 independent components), I want to figure out the spread of the first and sec...

2 years ago | 1 answer | 0

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Question

how can I increase the performance of this loop?
nPts = 15; a = linspace(0.1, 2.0, nPts); b = linspace(0.1, 2.0, nPts); c = linspace(0.1, 2.0, nPts); d = linspace(-0.3, 2....

2 years ago | 1 answer | 0

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Question

scatteredInterpolant: what is linear interpolation in 2d?
%coords supportPts = [3 3; 3.3 3; 3 3.25; 3.3 3.25; 3.6 3; 3.6 3.25; 3 3.5; 3.3 3.5; 3.6 3.5]; %values Fval = [0 0.1121 0.064...

2 years ago | 1 answer | 0

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Answered
can I pass these nonlinear constraints to lsqnonlin?
residual =[residual; smallnumber*[diff(G,2);diff(H,2)]] This is an equivalent way to implement my suggestion I just realize th...

2 years ago | 0

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c++ engine API: minimal example gives segmentation fault, see stacktrace
I built an c++ API engine using a minimal example as shown here https://de.mathworks.com/help/matlab/matlab_external/test-your-...

2 years ago | 1 answer | 0

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Question

bilinear extrapolation based on interp2
[X,Y] = meshgrid(0:10); Z = X.^2 + Y.^2; [Xq,Yq] = meshgrid(0:0.25,10); V = interp2(X,Y,Z,Xq,Vq,'linear'); I want to use int...

2 years ago | 2 answers | 1

2

answers

Question

can I pass these nonlinear constraints to lsqnonlin?
Let denote a function of two variables and the parameters of the optimization problem which I want to solve with lsqnonli...

2 years ago | 3 answers | 0

3

answers

Question

symbolic differentiation to find analytical expressions that are time-consuming to calculate manually?
Given a function of two variables f(x,y) = I want to find the analytial expression of the determinant of the Hessian of . ar...

2 years ago | 0 answers | 0

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Question

lsqnonlin optimization: large condition number of Jacobian matrix at all iterations, but full rank
I use lsqnonlin to solve a non-linear data-fitting problem (fitting parameters of a partial differential equation). The minimiza...

2 years ago | 2 answers | 1

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answers