# Bill Tubbs

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**Content Feed**

Question

The statement "order of the polynomial B(q) + 1" in the documentation is somewhat ambiguous

The following statement appears in a number of places in the documentation and refers to the nb parameter of discrete linear sys...

25 days ago | 0 answers | 0

### 0

answersQuestion

How to include a disturbance forecast in MPC Simulink block

I'm familiar with how to have a measured disturbance input to an MPC but I also want to include a forecast (i.e. future predicti...

2 months ago | 0 answers | 0

### 0

answersHow 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...

6 months 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...

6 months ago | 1 answer | 0

### 1

answerQuestion

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. ...

7 months ago | 1 answer | 0

### 1

answerCompute 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...

8 months 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...

8 months ago | 2 answers | 0

### 2

answersHow 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,...

8 months 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...

9 months 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...

9 months ago | 1 answer | 0

### 1

answerMultiple 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...

10 months 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...

10 months ago | 1 answer | 0

### 1

answerQuestion

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...

10 months ago | 2 answers | 0

### 2

answersLoop over fieldnames in a matlab structure

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

10 months 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...

10 months 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...

10 months ago | 1 answer | 0

### 1

answerSpecifying 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...

12 months 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...

1 year ago | 2 answers | 0

### 2

answersHow 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

1 year ago | 1

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 ...

1 year 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...

1 year ago | 0 answers | 0

### 0

answersQuestion

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...

1 year ago | 1 answer | 0

### 1

answerAdvice on adding a manipulatable variable target to MPC

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

1 year ago | 0

| accepted

Question

Advice on adding a manipulatable variable target to MPC

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

1 year ago | 1 answer | 0

### 1

answerTrying 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...

1 year 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...

1 year ago | 1 answer | 0

### 1

answerHow 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...

1 year 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...

1 year 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...

1 year ago | 0

Question

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

FYI, I asked a similar question about this problem before but did not get a satisfactory answer so I'll ask it in a different wa...

1 year ago | 2 answers | 0