# Are Mjaavatten

Last seen: 6 giorni fa Attivo dal 2015

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

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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 ...

oltre un anno fa | 2

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Domanda

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 = ...

oltre 2 anni fa | 1 risposta | 0

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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,...

quasi 3 anni fa | 0

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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 ...

quasi 3 anni fa | 0

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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)....

quasi 3 anni fa | 0

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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: >...

quasi 3 anni fa | 0

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

circa 3 anni fa | 1

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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...

circa 3 anni fa | 0

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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 ...

oltre 3 anni fa | 0

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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...

oltre 3 anni fa | 0

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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 ...

oltre 3 anni fa | 0

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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...

oltre 3 anni fa | 0

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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...

oltre 3 anni fa | 0

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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...

quasi 4 anni fa | 0

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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...

quasi 4 anni fa | 0

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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 ...

circa 4 anni fa | 1

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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...

circa 4 anni fa | 0

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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...

circa 4 anni fa | 3

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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 = ...

circa 4 anni fa | 1

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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...

circa 4 anni fa | 0

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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)*...

circa 4 anni fa | 2

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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...

circa 4 anni fa | 0

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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...

circa 4 anni fa | 0

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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...

oltre 4 anni fa | 0

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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; ...

oltre 4 anni fa | 0

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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...

oltre 4 anni fa | 0

Domanda

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...

oltre 4 anni fa | 2 risposte | 2

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Domanda

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...

oltre 4 anni fa | 2 risposte | 0

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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...

oltre 4 anni fa | 0

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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...

quasi 5 anni fa | 0

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