# Are Mjaavatten

Last seen: ein Tag vor Aktiv seit 2015

Followers: 0   Following: 0

Retired physicist with background in the petroleum and process industry. My main interests are mathematical modelling, numerical methods, and thermodynamics.

#### Statistik

All

Abzeichen anzeigen

#### Feeds

Anzeigen nach

Beantwortet
Difficulty Finding Hydrogen (H2) Properties for Gas Properties (G) Block
The real gas option in Simscape requires tables of properties as functions of temperature and pressure. You will find the data ...

mehr als ein Jahr vor | 2

| akzeptiert

Frage

How do I create a table containing a character array if it has only one row?
This works fine: Time = [1;2];Force = [12;17];ID = ['ab';'cd']; T = table(Time,Force,ID) But this fails: Time = [1];Force = ...

mehr als 2 Jahre vor | 1 Antwort | 0

### 1

Antwort

Beantwortet
Error in setdiff function
One workaround is to replace all NaNs with some spceific value that is not present in your data, say -9999: >> S1 = [1,2,3,NaN,...

etwa 3 Jahre vor | 0

Beantwortet
How can I solve an ode where one of the variables is a matrix?
A(t) should be a function, not a vector. Below I define A as an anonymous function. I also use an anonymous function for your ...

etwa 3 Jahre vor | 0

| akzeptiert

Beantwortet
4D data /Index exceed array bounds
I think it may be better to let M_Val be a cell array of 5 ordinary arrays, where M_Val{k} is of dimension 134 by 2 by nsyll(k)....

etwa 3 Jahre vor | 0

Beantwortet
4D data /Index exceed array bounds
I think you may have inadvertently created a cell array containing your whole data matrix in element 1. Something like this: >...

etwa 3 Jahre vor | 0

Beantwortet
How to find index range of range of values in an array
i = find(x>=69 & x<=72);;

mehr als 3 Jahre vor | 1

Beantwortet
y coordinates of center of buoyancy
Is this what you want? x = [-8,-8,-6,0,6,8,8,-8]; y = [10,5,1,0,1,5,10,10]; ship=polyshape(x,y); figure(1) clf hold on p...

mehr als 3 Jahre vor | 0

Beantwortet
Is it possible to convert a cell array into individual variables on workspace?
Dynamically creating variables in Matlab is not encouraged. See Stephen Cobeldick's tutorial entry. A better idea is to create ...

mehr als 3 Jahre vor | 0

Beantwortet
How to plot a trinomial graph
fun = @(x) x^3; fplot(fun,[-3,3]) Alternatively: x = linspace(-3,3); plot(x,x.^3); % Note the use of .^, for element by ele...

mehr als 3 Jahre vor | 0

Beantwortet
Fitting a 3D gaussian to a 3D matrix
meshgrid arranges the xx and yy output matrices to fit the convention where the surface plots have x on the horizontal axis and ...

mehr als 3 Jahre vor | 0

Beantwortet
For loop assistance- incorrect data
You give DATA.s(3,1) the desired value in line 8 of exec2w. Then you overwrite it with the wrong value in line 22. I found deb...

mehr als 3 Jahre vor | 0

Beantwortet
How can resolve r0<=r0_max?
I interpret your question to mean that you want copertura{mm,nn}(k,1) to take the value 1 if r0{mm,nn}(k,1) <= r0_max(mm,nn), an...

mehr als 3 Jahre vor | 0

Beantwortet
Increasing precision of second order boundary value problem
Your asymptotic expansion solution seems to have zero slope at y = 0. This implies that the second derivative is zero and the s...

fast 4 Jahre vor | 0

Beantwortet
Error using + Matrix dimensions must agree.
In line 43, x(:,i) is a column vector, while k1' is a row vector. Summing a column vector and a row vector is not allowed in ol...

etwa 4 Jahre vor | 0

Beantwortet
Golden Section Search algorithm, golden number why is 0.381
Let and be the end points of the current range. In golden ratio search we choose a new point such that the ratio of the two ...

etwa 4 Jahre vor | 1

Beantwortet
Problem relating to mathematical expression
Ameer's answer is correct, of course. Here is another approach, without the elegant Matlab functions: N = 5; % Max window size...

etwa 4 Jahre vor | 0

Beantwortet
Help text does not work for user-defined functions
Problem solved - finally! My Matlab 2019b and 2020a installations had several other odd behaviours in addition to the help prob...

etwa 4 Jahre vor | 3

| akzeptiert

Beantwortet
Solution for system of two non linear equation
You can rewrite you equations as (Nd-x-y)-a*(x*(x+y)) = 0 (Nd-x-y)*(No-y)-b*(y*(x-y)) = 0 where x = Nd, y = Nonegative, a = ...

etwa 4 Jahre vor | 1

| akzeptiert

Beantwortet
Problem of erf when using fmincon
Your problem has infinitely many solutions. Whenver x(1)-x(3) = 1 and x(2)-x(4) = 1, fun = 0, which is the minimum value possib...

etwa 4 Jahre vor | 0

Beantwortet
how to Nonlinear equations?(two variables)
Although R1 and R2 are nonlinear finctions of t, your equations are linear in x. So you write the equations on the form A(t)*...

mehr als 4 Jahre vor | 2

| akzeptiert

Beantwortet
How to count number of times a number appears in column B based on column A
letters = 'ABAACD'; numbers = [1,2,2,1,1,3]; uniqueletters = unique(letters); uniquenumbers = unique(numbers); n = length(un...

mehr als 4 Jahre vor | 0

| akzeptiert

Beantwortet
Van der Waals equation - Newton's method
In your code, newton_ndim does not know the value of T and so cannot call fun(X,T). You can probably fix this by defining an in...

mehr als 4 Jahre vor | 0

| akzeptiert

Beantwortet
How do I solve system of equations?
If I understand you correctly, your system consist of 128 eqations. a and b are arrays of 64 unknowns each. You must then solv...

mehr als 4 Jahre vor | 0

| akzeptiert

Beantwortet
Join repeated continuous elements of a vector
in = [1 1 1 2 2 3 6 6 6 1 1 1 4 4 4 2 2 2 6 4 4]; i = 1; count = 1; out = []; a = in(1); while i < length(in) i = i+1; ...

mehr als 4 Jahre vor | 0

Beantwortet
Fsolve don't work good with trigonometric
Your function has several different zeros. Which one fsolve finds will depend on the starting point. I ran: f = 100; while no...

mehr als 4 Jahre vor | 0

Frage

Help text does not work for user-defined functions
I just installed R2019b and the help function does not work. Example: I created the addme function from the Add Help for Your P...

mehr als 4 Jahre vor | 2 Antworten | 2

### 2

Antworten

Frage

Is there a way to avoid repeating time-consuming calculations from odefun in the events function?
The right-hand side in my ODE is quite time-consuming. In the course of calculating dy/dt I calculate a variable u that I also u...

fast 5 Jahre vor | 2 Antworten | 0

### 2

Antworten

Beantwortet
First order ODE parameter fit to dataset
The challenge is how to use your table of temperatures in your updateStates function. At a given time t, you must interpolate y...

fast 5 Jahre vor | 0

| akzeptiert

Beantwortet
How to calculate a curve for different variables?
Here is one way to do it. I have reduced the number of elements in your Time and V vectors in order to make a nicer surface plo...

fast 5 Jahre vor | 0

| akzeptiert