SA-W

Last seen: 3 Monate vor | Aktiv seit 2021

Followers: 0 Following: 0

Statistik

Feeds

Frage

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 Monate vor | 1 Antwort | 0

1

Antwort

Frage

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 Monate vor | 0 Antworten | 0

0

Antworten

Frage

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 ...

7 Monate vor | 1 Antwort | 0

1

Antwort

Frage

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 Monate vor | 2 Antworten | 0

2

Antworten

Frage

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 Monate vor | 3 Antworten | 0

3

Antworten

Frage

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 Monate vor | 2 Antworten | 0

2

Antworten

Frage

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...

mehr als ein Jahr vor | 2 Antworten | 0

2

Antworten

Frage

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...

mehr als ein Jahr vor | 1 Antwort | 0

1

Antwort

Frage

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...

mehr als ein Jahr vor | 1 Antwort | 0

1

Antwort

Frage

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); ...

mehr als ein Jahr vor | 1 Antwort | 0

1

Antwort

Frage

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(...

mehr als ein Jahr vor | 1 Antwort | 0

1

Antwort

Frage

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...

mehr als ein Jahr vor | 1 Antwort | 0

1

Antwort

Frage

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...

mehr als ein Jahr vor | 3 Antworten | 0

3

Antworten

Frage

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...

mehr als ein Jahr vor | 5 Antworten | 0

5

Antworten

Frage

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',...

fast 2 Jahre vor | 1 Antwort | 1

1

Antwort

Frage

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...

fast 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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...

fast 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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 ...

fast 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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...

fast 2 Jahre vor | 2 Antworten | 0

2

Antworten

Frage

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...

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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; ...

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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...

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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....

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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...

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Beantwortet
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...

etwa 2 Jahre vor | 0

Frage

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-...

etwa 2 Jahre vor | 1 Antwort | 0

1

Antwort

Frage

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...

etwa 2 Jahre vor | 2 Antworten | 1

2

Antworten

Frage

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...

etwa 2 Jahre vor | 3 Antworten | 0

3

Antworten

Frage

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...

etwa 2 Jahre vor | 0 Antworten | 0

0

Antworten

Frage

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...

mehr als 2 Jahre vor | 2 Antworten | 1

2

Antworten

Mehr laden