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# Bill Tubbs

Last seen: Today Active since 2020

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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...

19 days ago | 0

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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...

19 days 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...

29 days ago | 1

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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...

29 days ago | 1 answer | 0

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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...

1 month 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{:})) ...

1 month 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...

2 months ago | 0

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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...

2 months 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...

3 months ago | 0

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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...

5 months 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

5 months 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 ...

5 months ago | 0

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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...

5 months ago | 0 answers | 0

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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...

6 months 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 ...

6 months ago | 0

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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...

6 months 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...

6 months ago | 0

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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...

6 months 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...

6 months 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...

6 months 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...

7 months ago | 0

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

7 months 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...

7 months ago | 0

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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 =...

7 months ago | 1 answer | 0

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Reset method being called twice during instantiation of a class instance with inheritance
I'm defining various classes with an inheritance hierarchy and having problems setting up each class's reset method so that it i...

8 months ago | 1 answer | 0

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How to extract matches from results of a regexp match
Here is a one-line solution—it's based on the answer of Stephen23 but instead of finding the matches, it finds the first indeces...

9 months ago | 0

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How to make an inherited immutable super class property mutable in the sub-class?
I have a class which has immutable properties and I want some sub-classes to be able to modify these properties. Obviously it r...

9 months ago | 1 answer | 0

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Question

Strings are converted to cells during readtable
I am incrementally saving data to a csv file which includes strings: data = table("string1", "string2"); writetable(data, "dat...

10 months ago | 2 answers | 0

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How do I create one legend for several subplots?
This is a good answer: Raghu S on 30 Aug 2018

10 months ago | 0

Question

How to extract matches from results of a regexp match
I'm trying to find the columns of a table that match a pattern. This works: col_names = {'X_est_9', 'X_est_10', 'Y_est_9', 'Y...

10 months ago | 3 answers | 0