Community Profile # Paul Rogers

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30 total contributions since 2019

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Question

finding the error between two curves from a fig
I have a fig, the onee in attaced (example). Considering the green one the true value, how can I evaluete the error of the seco...

2 months ago | 1 answer | 0

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Question

finding elements in a vector from another vector
I'd like to create a vector y with the positions of the elements of x in m. i.e. x=0 (first element of x) has and index of 1 i...

2 months ago | 2 answers | 0

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Question

extracting only real numbers (not real part) from a vector
I have these 2 vector, phi, and psi. both have complex number from the 1st to 4864th element, then from 4865th to the last real...

2 months ago | 1 answer | 0

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Question

Has anyone of you ever asked for help and paid? I was asked some money and a bit worry of getting scammed. Any opinions or pas...

2 months ago | 1 answer | 0

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Question

iteration with for for a simple computation
I'd like do write this expression in a more compact and generic way, like with a for: T = c(1)*cos(0) + c(2).*cos(1.*acos((m)))...

2 months ago | 1 answer | 0

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polynomial evaluation for a simple curve.
formula = ((x.^4)*-35.4628) + ((x.^3)*39.9257) + ((x.^2)*-14.8278) + ((x.^1)*1.6022) + ((x.^0)*1.1031);

3 months ago | 0

| accepted

Question

polynomial evaluation for a simple curve.
After I got the coefficent from the command: p1=polyfit(x,y,4); the p1 vector is: p1 = -35.4628 39.9257 -14.8278 1...

3 months ago | 1 answer | 0

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Question

vector multiplied a matrix
Hi, I need this multiplication and I can't whats wrong f=c.*T where c and T are the attached files. so I expect a raw vector ...

3 months ago | 2 answers | 0

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Question

multiplying vectors (easy one!)
Sorry guys, an easy question: how do I evaluete this function in the interval x=[-0.2,0.8] the function is f = 2.2785*T_0(x) ...

3 months ago | 1 answer | 0

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Chebishev polynomials, don't know how to use "chebpoly"
Can anyone help me on how to find T_i and T_j?

4 months ago | 0

Chebishev polynomials, don't know how to use "chebpoly"
maybe this can help By Chebyshev points we shall mean the set of points in [−1,1] defined by xj=−cos(jπ/N), 0≤j≤N, where N≥...

4 months ago | 0

Question

Chebishev polynomials, don't know how to use "chebpoly"
I wrote the following code to approximate a 2 variables function: clear clc close all FlowMeasurements = chebpts(5,[-0.2,0...

4 months ago | 2 answers | 0

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Question

Getting coefficient from a chebfun (chebcoeffs2-chebpoly)
I worte the following code to get an apprroximation of a compressor map: clear clc close all FlowMeasurements = c...

4 months ago | 0 answers | 0

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Question

Invisible data? Where are they stored?
Hi everyone, I wrote a code from a tool I am not expert about at all (chebfun). I managed to make it work and run. What I am m...

4 months ago | 1 answer | 0

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Question

Jus a simple expression (easy question)
Hi guys, I am just having some iussues with this formula, could some one please help me? n=5, r=5.

4 months ago | 1 answer | 0

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Question

simple for cycle!
I have one vector: massa=massa = -0.2000 -0.1932 -0.1729 -0.1397 -0.0946 -0.0386 0.0265 0.0...

8 months ago | 1 answer | 0

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Question

where are my data?
I plot a figure by using a function from a package. Now I'd like to know the x and y values once I plot the curve. Where are t...

8 months ago | 1 answer | 0

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selection of certain data from matrix
I finally did this way: for i=1:length(FlowMeasurements) if FlowMeasurements(i) < 0 CompressorMapMatrix(:,i) = ...

8 months ago | 0

| accepted

Question

selection of certain data from matrix
Hi, my problem is that I have 3 matrix: FlowMeasurements, psic_pos_cheb and psic_neg_cheb. I need a matrix done this way with:...

8 months ago | 2 answers | 0

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Question

Polyfit minus one term
Hi, and happy new year. I need a 3rd order polynomiial approximation for the file Data001 in attached. I can use polyfit but I...

9 months ago | 2 answers | 0

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Question

Too many output arguments.
I've found this code that may help me a lot. I cannot run, it keeps saying: Error using type Too many output arguments. my v...

9 months ago | 1 answer | 0

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Question

Reference to non-existent field 'D1t'.
hi there, I need to run the file "Integration" I found in the web. the input parameters are: N: 54000 Pin: 100000 T: 303.35...

9 months ago | 1 answer | 0

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Question

divide a matrix per a vector
Hi, I have a matrix A(7x1001) and a matrix B(1x7). I'd like to divide the first row of A for the first colum(element) of B, se...

9 months ago | 1 answer | 0

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polyfit and polyval problem
here we are, I think I found the solution. I can select only a portion of that curve and take the x and y values, then the co...

10 months ago | 0

| accepted

Question

polyfit and polyval problem
Hi there, I am trying to plot a line using the ployfit and command x and y are the coordinates in attached xy the plot. I ca...

10 months ago | 1 answer | 0

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Question

Subtracting Vector from a Matrix
I have the matrix a (8x1001) and b (1x1001) as in attached. a and b can change in size. How do I substract b from each row of ...

10 months ago | 2 answers | 0

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Question

Legend in a "for loop"
hi, I need to insert a legend for each ii evalueted. giri can change in size at every simulation. for ii=1:length(giri) fig...

10 months ago | 1 answer | 0

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Question

find elements vector in a matrix
Hi, I have a matrix A 3x1201 and a vector B 3 elements. (A and B can change size but B will alway have the size of A row's). ...

11 months ago | 1 answer | 0

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Question

How do I plot eta only when it's then 0?
Hi everybody, and thanks for your help. I need some help for the gollowing code: print rendimento only when eta>0 evalute p02...

11 months ago | 1 answer | 0