# SA-W

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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...

2 months ago | 2 answers | 0

### 2

answersQuestion

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...

2 months ago | 1 answer | 0

### 1

answerQuestion

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...

3 months ago | 1 answer | 0

### 1

answerQuestion

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); ...

3 months ago | 1 answer | 0

### 1

answerQuestion

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(...

3 months ago | 1 answer | 0

### 1

answerQuestion

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...

4 months ago | 1 answer | 0

### 1

answerQuestion

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...

4 months ago | 3 answers | 0

### 3

answersQuestion

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...

5 months ago | 5 answers | 0

### 5

answersQuestion

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',...

7 months ago | 1 answer | 1

### 1

answerQuestion

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...

7 months ago | 1 answer | 0

### 1

answerQuestion

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...

7 months ago | 1 answer | 0

### 1

answerQuestion

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 ...

9 months ago | 1 answer | 0

### 1

answerQuestion

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...

9 months ago | 2 answers | 0

### 2

answersQuestion

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...

11 months ago | 1 answer | 0

### 1

answerQuestion

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; ...

11 months ago | 1 answer | 0

### 1

answerQuestion

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...

11 months ago | 1 answer | 0

### 1

answerQuestion

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....

11 months ago | 1 answer | 0

### 1

answerQuestion

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...

12 months ago | 1 answer | 0

### 1

answercan 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...

12 months ago | 0

Question

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-...

12 months ago | 1 answer | 0

### 1

answerQuestion

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...

12 months ago | 2 answers | 1

### 2

answersQuestion

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...

12 months ago | 3 answers | 0

### 3

answersQuestion

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...

1 year ago | 0 answers | 0

### 0

answersQuestion

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...

1 year ago | 2 answers | 1

### 2

answersQuestion

source code of multistart in global optimization toolbox

I am currently using multistart to perform optimization with multiple start vectors. ms = Multistart(...) ... = run(ms,...) ...

1 year ago | 1 answer | 0

### 1

answerQuestion

import bubblechart in latex document and typeset text (x-labels,...) by latex -- possible?

I created two bubblecharts next to each other in a tiledlayout(1,2) and want to include it in my tex document. Both matlab2tikz...

1 year ago | 1 answer | 0

### 1

answerQuestion

gradient of bubble colors in a bubble chart

I want to create a bubblechart with three different bubble colors. One group of bubbles is red, the second group is blue, and ...

1 year ago | 1 answer | 0

### 1

answerQuestion

natural cubic spline interpolation of y-values: how to get derivative of the spline wrt the y-values?

Given a data set with support points x_1,...,x_n and corresponding y-values y_1,...,y_n. My objective is to create a cubic spli...

1 year ago | 3 answers | 0

### 3

answersQuestion

optimization: have function return NaN but not at initial point

I use fmincon interior-point algoritm to solve my optimization problem. Based on Matlab's recommendation, I let my function re...

1 year ago | 1 answer | 1

### 1

answerQuestion

is the objective function stochastic (-> use something like patternsearch) or deterministic?

My objective function is given by f(x) = ||d^sim(x) - d^exp||^2 d^exp is a constant vector of measurements, to which I add ra...

1 year ago | 1 answer | 0