# Michal

Last seen: Today Active since 2015

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Programming Languages:
MATLAB, Fortran
Spoken Languages:
English

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Question

fast evaluation of x(k+1) = x(k)*e(k)
Is there any special trick how to evaluate fast this recurrent formula: x(1) = x0 x(k+1) = x(k)*e(k), k= 1,2, ...N-1 where N...

5 maanden ago | 1 answer | 0

### 1

Question

extremely inefficient piece of code ... bug?
I have two codes that implement exactly the same task: idx(idx<=0) = 1; idx(idx>=n) = n-1; and if idx <= 0 ...

9 maanden ago | 1 answer | 0

### 1

linear 1st order ODEs sytem with time-dependent coefficients solver
This problem is now (starting from R2023a) fully covered by LTV models implemented at Control System Toolbox. These LTV models a...

10 maanden ago | 0

| accepted

linear 1st order ODEs sytem with time-dependent coefficients solver
There are two available toolboxes for time-dependent linear 1st order ODEs: LTVtools: https://www.mathworks.com/matlabcentral...

10 maanden ago | 0

Question

linear 1st order ODEs sytem with time-dependent coefficients solver
I need to solve many times the following ODEs system: F'(t) = A(t)*F(t) + B(t)*U(t) F(0) = F0 where matrices A(t), B(t) and v...

10 maanden ago | 2 answers | 0

### 2

Question

simplify is not realible
How to simplify the folowing very simple expression: syms a b c e1 = -(b*(b^2 - 4*a*c)^(1/2) - 4*a*c + b^2)/(2*a*(b^2 - 4*a*c)...

ongeveer een jaar ago | 0 answers | 0

### 0

Question

Merging piecewise polynomial (pp) structures
Is there any method how to merge two or more "pp" (peicewise polynomial) structures in a case of consecutive "pp" structures wi...

ongeveer een jaar ago | 3 answers | 0

### 3

Question

MATLABConnector startup on Linux
Last two versios of MATLABConnector for Linux automatically put the app to the startup list, but in Preferereces settings is not...

ongeveer een jaar ago | 1 answer | 0

### 1

Warning: X does not support locale en_US.UTF-8
Official TMW statement: "This is a warning message that can be disregarded and it has no impact on the functionality of MATLAB....

ongeveer een jaar ago | 5

| accepted

Question

Warning: X does not support locale en_US.UTF-8
After application of R2022b_upd5 on linux mint (21.1 Cinammon) I always get the following warning at the startup: Warning: X doe...

ongeveer een jaar ago | 4 answers | 3

### 4

Question

Volterra integral equation solver
I am looking for good (fast and accurate, with recent state of art methods) numerical (not symbolic) Volterra Integral Equation ...

meer dan een jaar ago | 0 answers | 0

### 0

Question

strange performance behavior - microbenchmark
There are two implementations of the same algorithm: function B = alg1( B, R, alpha ) % Fast computation of L1 distance transf...

meer dan een jaar ago | 1 answer | 0

### 1

How do I speed up lsim computation in a for loop?
Better than naive using of parfor loop is transform to your final simulation model to the sparse form ... see here Transform m...

meer dan een jaar ago | 0

Why does MATLAB crash on Linux with "Inconsistency detected by ld.so: ../elf/dl-tls.c: 597: _dl_allocate_tls_init:"
I have similar problem with MATLAB coder on R2022b (Ubuntu Linux 20.04.3) >> coder >> Inconsistency detected by ld.so: ../elf/...

meer dan een jaar ago | 6

Question

INTEL oneAPI support for linux MATLAB
TMW officially does not support INTEL oneAPI compilers (C/C++ and Fortran), but only GCC and GFORTRAN on Linux platform. See her...

meer dan een jaar ago | 1 answer | 0

### 1

There is an official TMW statement ...

meer dan een jaar ago | 2

Question

Free-knot spline approximation (BSFK) problem
@BrunoLuong My data acquisition system produce periodically 1-D measured noised data with the fixed time window length W. I wa...

meer dan een jaar ago | 1 answer | 0

### 1

Use Java 11 jar files in Matlab
You can use following java compiler (javac) option: --release <release> Compile for a specific VM version. Supported targets: ...

meer dan een jaar ago | 0

| accepted

Question

support of Java11
What are the plans to to use Java11 in future MATLAB releases? So far is still using Java 1.8, but Java 11 is now standard defau...

meer dan een jaar ago | 2 answers | 0

### 2

Question

decomposition used in parfor
In the following problem, where I need to solve many times same linear system "A" with different right sides "b" is very benefit...

bijna 2 jaar ago | 1 answer | 1

### 1

symbolic integration depends on different equivalent forms of function

bijna 2 jaar ago | 0

Question

symbolic integration depends on different equivalent forms of function
I performed the following equaivalent symbolic integrations: syms x y A = int(x+y,x); A_ = expand(A); % just expanded...

bijna 2 jaar ago | 2 answers | 0

### 2

Question

multi array vectorization problem (reformulated)
How to vectorize (for-loop elimination) the following code? % init A = [ -0.8013 -0.4981; -0.2278 -0.9009]; t = 0:0.01:...

ongeveer 2 jaar ago | 3 answers | 0

### 3

Question

How to formulate linear control problem for Stochastic Differential Equation solvers
I have the following linear control problem: x'(t) = A*x(t) + B*u(t) y(t) = C*x(t) + D*u(t) where x(t0) = x0 ... initial co...

ongeveer 2 jaar ago | 1 answer | 0

### 1

Question

Most effective way to solve nonhomogeneous linear ODE problem
What is the most effective way to solve following "small" linear 1st order ODEs problem: x'(t) = Ax(t) + Bu(t) x(t0) = x0 whe...

ongeveer 2 jaar ago | 1 answer | 0

### 1

Use Filter Constants to Hard Code Filter
Probably fully functional naive version of filter: function [Y, z] = myFilter(b, a, X, z) % a and b should have same order...

meer dan 2 jaar ago | 0

Question

Algorithm for homogenization of non-equidistant 1-D grid
I am looking for proper algorithm for so called "delta-homogenization" of 1-D non-equidistant grid. Definition: The sorted mono...

meer dan 2 jaar ago | 0 answers | 0

### 0

Question

Matlab is significantly slower than Julia on simple evaluation
More and more frequently some people open the question about speed comparison between Matlab and Julia. The main Julia developer...

meer dan 2 jaar ago | 2 answers | 3

### 2

Question

expm function problem for stiff matrix
For very specific matrix A: a = -1e20; b = eps; c = 1; A = [a,0,b;0,c,0;-b,0,a]; disp('A:'), disp(num2str(A)) A: ...

bijna 3 jaar ago | 3 answers | 1