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# Bill Tubbs

Last seen: 1 dag ago Active since 2020

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How to set number of measured disturbances to zero in MPC Designer
I figured it out. When you first add an MPC Controller to your simulink model, it has one measured disturbance input by default...

1 dag ago | 0

Question

How to set number of measured disturbances to zero in MPC Designer
I'm using the MPC Designer tool from Simulink for the first time. I have a system with one MV, one CV, and one unmeasured input...

1 dag ago | 1 answer | 0

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Question

Simulate a random walk that starts at a certain time and then stops before the end of the simulation
I want to simulate a white noise that begins at a certain time and then stops at another time before the end of the simulation. ...

12 dagen ago | 1 answer | 0

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Compute standard deviations of predictions of linear and polynomial regression models
Looking at the linear regression example, the mean predictions are in fact exactly half-way between the confidence intervals, a...

ongeveer 2 maanden ago | 0

Question

Compute standard deviations of predictions of linear and polynomial regression models
I'm using the fit and fitlm functions to fit various linear and polynomial regression models, and then using predict and predint...

ongeveer 2 maanden ago | 2 answers | 0

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How can I use a variable number of structure fields as function arguments?
I recently discovered the function namedargs2cell (since r2019b) and use it for this purpose: >> MyParams = struct('a',1,'b',2,...

ongeveer 2 maanden ago | 1

Using regressionLearner app—how to add models
I eventually figured out a workaround. It's not very intuitive. First you have to fit one of your models. Then select this mo...

3 maanden ago | 0

| accepted

Question

Using regressionLearner app—how to add models
I'm following this tutorial on how to use the regressionLearner app. At one point it says "Add medium and coarse tree models to...

3 maanden ago | 1 answer | 0

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Multiple dispatch problem when trying to call the feval function with a LinearModel as an argument.
There are some good suggested solutions to this from Cris Luengo on this parallel stackoverflow post: MATLAB "Too many output a...

3 maanden ago | 1

| accepted

Question

Multiple dispatch problem when trying to call the feval function with a LinearModel as an argument.
I set up a workflow where I am using feval to call functions programmatically and ran into a major stumbling block with one part...

3 maanden ago | 1 answer | 0

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Question

Gaussian process regression - how to fit a basis function but not other parameters
I'm doing Gaussian process regression with the fitrgp function and want to manually control some parameters such as the kernel p...

3 maanden ago | 0 answers | 0

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Loop over fieldnames in a matlab structure
There is another way to loop over the fieldnames: for field = fieldnames(mystruct)' if isstruct(mystruct.(field{:})) ...

3 maanden ago | 0

Rearrange Variables in an equation
As explained here by Paul, you can use the isolate function for this: >> syms a b >> eqn1 = b == (1 - a) / 2; >> isolate(eqn1...

4 maanden ago | 0

Question

How to simply rearrange a symbolic equation to get an expression for one variable in terms of others
I'm building differential equations symbolically and ran into an error when doing a simple re-arranging of an equation. For exa...

4 maanden ago | 1 answer | 0

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Specifying bounds in process model estimation
Not necessarily. You only need bounds if you think your model is overfitting the data (e.g. due to not enough data points and/o...

5 maanden ago | 0

Question

Test of whether matrix is Symmetric Positive Definite is giving wrong result when matrix is not symmetric
I'm computing a multivariate normal probability density with an estimated covariance matrix as follows: % Update the conditiona...

7 maanden ago | 2 answers | 0

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How to make an array of alternating 1 and -1?
Even easier: out = cumprod(-ones(1, 12)) out = -1 1 -1 1 -1 1 -1 1 -1 1 -1 1

7 maanden ago | 0

How to make an array of alternating 1 and -1?
Here's another way. A geometric series: out = (-1).^(0:11) out = 1 -1 1 -1 1 -1 1 -1 1 ...

7 maanden ago | 0

Question

Confusing description of built-in estimator noise model on MPC documentation page
I'm confused by the following text which appears on the documentation page: 'Implement Custom State Estimator Equivalent to Buil...

7 maanden ago | 0 answers | 0

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Question

How to assign values to MV Targets of MPC object from cell array
I'm having a tough time trying to assign 3 values to the parameters of an mpc object. Here is my MPC object with it's current v...

8 maanden ago | 1 answer | 0

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As usual, I figured it out a few minutes after posting this question! It actually says this in the documentation page I linked ...

8 maanden ago | 0

| accepted

Question

I've designed an MPC in MATLAB using the mpc function and successfully simulated it in Simulink using the MPC block in closed lo...

8 maanden ago | 1 answer | 0

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Trying to understand dimensions of state estimates output of MPC block in Simulink
I figured out that you can use the following to get all the parameters of the Kalman Filter including the augmented model used b...

8 maanden ago | 0

| accepted

Question

Trying to understand dimensions of state estimates output of MPC block in Simulink
I'm running an MPC in Simulink that was defined in a matlab script using the MPC Controller block and I want to inspect the stat...

8 maanden ago | 1 answer | 0

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How do I calculate the static Kalman gain (= steady-state Kalman gain)?
In addition to my answer above, I just discovered a special function for Kalman estimator design called dlqe in the Control Syst...

8 maanden ago | 0

How do I calculate the static Kalman gain (= steady-state Kalman gain)?
For the record, I found a way to do it using the idare function (see this material online: hw5sol.pdf from S. Boyd). This is fo...

8 maanden ago | 0

How to avoid duplicating code in the constructor and a reset method of a class with class inheritance.
I found one solution. If you put the reset code in a static method, you can call it from within the constructor. Not sure if th...

9 maanden ago | 0

Question

How to avoid duplicating code in the constructor and a reset method of a class with class inheritance.

9 maanden ago | 2 answers | 0

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Find index to rows of one matrix in another
I figured out the answer: >> [~, idx] = ismember(B, A, 'rows') idx = 1 3 2 2 In case you want to check that all row...

9 maanden ago | 0

| accepted

Question

Find index to rows of one matrix in another
Suppose I have two matrices: >> A = eye(3) A = 1 0 0 0 1 0 0 0 1 >> idx = [1 3 2 2]; >> B =...

9 maanden ago | 1 answer | 0