Answered

How can I find a p-value when dealing with a weighted sum of chi-square distributions?

HI Michael, Since this is a weighted sum instead of a weighted mixture (as I erroneously assumed), the calculation will be alon...

How can I find a p-value when dealing with a weighted sum of chi-square distributions?

HI Michael, Since this is a weighted sum instead of a weighted mixture (as I erroneously assumed), the calculation will be alon...

1 day ago | 0

Answered

Interpreting xcorr results compared to corrcoef

Hi Jonathan, For the input column vectors, corrcoeff subtracts the mean off of each one and normalizes each to be a unit vector...

Interpreting xcorr results compared to corrcoef

Hi Jonathan, For the input column vectors, corrcoeff subtracts the mean off of each one and normalizes each to be a unit vector...

3 days ago | 1

Answered

How to generate matrices that satisfies constraints on sum of row elements and sum of column elements?

Hi sharadhi, Here is an example for 3x3, where all the row and column sums are 100 (looks like you edited the original question...

How to generate matrices that satisfies constraints on sum of row elements and sum of column elements?

Hi sharadhi, Here is an example for 3x3, where all the row and column sums are 100 (looks like you edited the original question...

3 days ago | 0

Answered

Cumulative distribution function of a function of a random variable

Hi Franziska, a = 1.2; x = .2 y = a*(1+x)*(2/(1+ (1+x)^(1/(a-1))))^(a-1) xx = (y/a)/(2-(y/a)^(1/(a-1)))^(a-1) -1 % ...

Cumulative distribution function of a function of a random variable

Hi Franziska, a = 1.2; x = .2 y = a*(1+x)*(2/(1+ (1+x)^(1/(a-1))))^(a-1) xx = (y/a)/(2-(y/a)^(1/(a-1)))^(a-1) -1 % ...

5 days ago | 0

| accepted

Answered

FFT interpolation using zero-padding and the Chirp Z-Transform for a single tone sinusoid

Hi Matt, I made one minor change at the beginning of your code, replacing the first four lines with M = 100; m = linspace(0,1...

FFT interpolation using zero-padding and the Chirp Z-Transform for a single tone sinusoid

Hi Matt, I made one minor change at the beginning of your code, replacing the first four lines with M = 100; m = linspace(0,1...

7 days ago | 0

| accepted

Answered

Fourier transform of table signal

Hello fima, It’s true that the amplitude is off, but frequency is a much more serious issue. The time domain plot shows that t...

Fourier transform of table signal

Hello fima, It’s true that the amplitude is off, but frequency is a much more serious issue. The time domain plot shows that t...

7 days ago | 0

Answered

fourier transform of exp

HI Hadimargo, A few modifications are necessary to make this work out. oo First, in the time domain the exponential function i...

fourier transform of exp

HI Hadimargo, A few modifications are necessary to make this work out. oo First, in the time domain the exponential function i...

11 days ago | 1

| accepted

Answered

Generate random numbers from a mixture distribution

Hi Thomas. I presume you mean something like the following. A uniform random variable is used to create an index that picks fr...

Generate random numbers from a mixture distribution

Hi Thomas. I presume you mean something like the following. A uniform random variable is used to create an index that picks fr...

16 days ago | 2

Answered

How to rotate the plot attached(Truncated Pyramid) to make its sides parallel to its Axis.

Hi adam, two lines become y(m)=R*sind(n+45); x(m)=R*cosd(n+45);

How to rotate the plot attached(Truncated Pyramid) to make its sides parallel to its Axis.

Hi adam, two lines become y(m)=R*sind(n+45); x(m)=R*cosd(n+45);

23 days ago | 0

| accepted

Answered

Trouble with MATLAB Triple Integral

Hi Goerge, The problem with the func([x,y,z]) approach is that there is too much expectation that [x,y,x] is 1x3. Once the int...

Trouble with MATLAB Triple Integral

Hi Goerge, The problem with the func([x,y,z]) approach is that there is too much expectation that [x,y,x] is 1x3. Once the int...

25 days ago | 0

| accepted

Answered

Linear interpolation with multiple values for each point

Hi Justin, If the problem is what I think it is, with d and e known, linear interpolation between o and p determined by a<d<b ...

Linear interpolation with multiple values for each point

Hi Justin, If the problem is what I think it is, with d and e known, linear interpolation between o and p determined by a<d<b ...

25 days ago | 0

Answered

Problem with the Color Bar

Hi Hans, try colormap(jet) colorbar by default this has 64 color levels (as does the default colormap, 'parula') and looks m...

Problem with the Color Bar

Hi Hans, try colormap(jet) colorbar by default this has 64 color levels (as does the default colormap, 'parula') and looks m...

27 days ago | 1

| accepted

Answered

Question about fft2(2D Fourier Transform) of a Gaussian function

Hi Zhu Li, A couple of things are going on here. First, there is the checkerboard pattern in the angle plot. I added an extra ...

Question about fft2(2D Fourier Transform) of a Gaussian function

Hi Zhu Li, A couple of things are going on here. First, there is the checkerboard pattern in the angle plot. I added an extra ...

30 days ago | 1

| accepted

Answered

The power sum of all frequencies seems that the half amount of the middle frequency power is not added. But the algorithm accords with the Parseval theorem. why?

Hi H^2, It helps that you are doing this for four frequencies rather than some crazy huge number of them. x = 1:4; N = length...

The power sum of all frequencies seems that the half amount of the middle frequency power is not added. But the algorithm accords with the Parseval theorem. why?

Hi H^2, It helps that you are doing this for four frequencies rather than some crazy huge number of them. x = 1:4; N = length...

1 month ago | 0

| accepted

Answered

Problem with symbolic Fourier Transform

Hello Halil, For the delta function, delta(x-x0) = |a| delta(a(x-x0)) so with a = 2*pi, both versions are correct. quick lo...

Problem with symbolic Fourier Transform

Hello Halil, For the delta function, delta(x-x0) = |a| delta(a(x-x0)) so with a = 2*pi, both versions are correct. quick lo...

1 month ago | 1

Answered

How does function std process complex numbers

Hi JFz, First of all, for a matrix the std is calculated independently for each column, as is true of many Matlab functions. F...

How does function std process complex numbers

Hi JFz, First of all, for a matrix the std is calculated independently for each column, as is true of many Matlab functions. F...

1 month ago | 1

| accepted

Answered

Simple squaring of expression

HI Wesley, syms a syms b syms c syms d syms e f = expand((1*a+2*b+3*c+4*d+5*e-8)*(1*a+2*b+3*c+4*d+5*e-8))

Simple squaring of expression

HI Wesley, syms a syms b syms c syms d syms e f = expand((1*a+2*b+3*c+4*d+5*e-8)*(1*a+2*b+3*c+4*d+5*e-8))

1 month ago | 0

| accepted

Answered

How to solve this equation which contains complex number, bessel equation and its derivative?

Hi bohan shen, The first six roots are shown below. First, since J1 is odd and J0,J2 are even, if z is a root then so is -z. ...

How to solve this equation which contains complex number, bessel equation and its derivative?

Hi bohan shen, The first six roots are shown below. First, since J1 is odd and J0,J2 are even, if z is a root then so is -z. ...

1 month ago | 1

| accepted

Answered

How do I assign matrix of strings to matrix of numbers?

Hi [A,B,C,D,E,F] = deal(5,8,2,9,2,1) although for a large number of variables, giving each its own name is not a winning strate...

How do I assign matrix of strings to matrix of numbers?

Hi [A,B,C,D,E,F] = deal(5,8,2,9,2,1) although for a large number of variables, giving each its own name is not a winning strate...

1 month ago | 0

| accepted

Answered

Finding and plotting radial component in vector field

Hi djr, nc = 14; nr = 14; % Create grid [x,y] = meshgrid(0:dx:(nc-1)*dx,0:dy:(nr-1)*dy); % Plot vectors (rows and colomns ne...

Finding and plotting radial component in vector field

Hi djr, nc = 14; nr = 14; % Create grid [x,y] = meshgrid(0:dx:(nc-1)*dx,0:dy:(nr-1)*dy); % Plot vectors (rows and colomns ne...

1 month ago | 0

| accepted

Answered

How to solve first-order nonlinear differential equation where the solution is coupled with an integral?

Hi Califfo; This may be in line with what you want. At least it's changing size It's based on the idea that you know not onl...

How to solve first-order nonlinear differential equation where the solution is coupled with an integral?

Hi Califfo; This may be in line with what you want. At least it's changing size It's based on the idea that you know not onl...

2 months ago | 2

| accepted

Answered

Errors when solving equation numerically with a Heaviside Theta

Hi A7, The code below finds a solution. Instead of looking for phi0 directly it uses the variable beta = 1/(lambda*phi0) Sin...

Errors when solving equation numerically with a Heaviside Theta

Hi A7, The code below finds a solution. Instead of looking for phi0 directly it uses the variable beta = 1/(lambda*phi0) Sin...

2 months ago | 0

Answered

Randomly select an element from a vector satisfying a condition

Relative speeds are going to depend on the length of X and the value N that the elements have to be greater than, (2 in the exam...

Randomly select an element from a vector satisfying a condition

Relative speeds are going to depend on the length of X and the value N that the elements have to be greater than, (2 in the exam...

2 months ago | 0

Answered

Matrix grouping result of combinations

Hello Joao, Maybe I need to write better blurbs. Here is a general solution for even n, with a verification check that shows t...

Matrix grouping result of combinations

Hello Joao, Maybe I need to write better blurbs. Here is a general solution for even n, with a verification check that shows t...

2 months ago | 0

Answered

Mesh doesn't work for cone shape?

Hello TY, I don't know if you need a fancier triangular mesh, but here is a way to a 'square' one. r = 0:.05:1; th = linspace...

Mesh doesn't work for cone shape?

Hello TY, I don't know if you need a fancier triangular mesh, but here is a way to a 'square' one. r = 0:.05:1; th = linspace...

2 months ago | 0

| accepted

Answered

Standard deviation of decimal numbers

Hi Jill, This is just the usual numerical 'error' due to the limitations of floating point arithmetic. std(.1*(ones(1,1e5)))...

Standard deviation of decimal numbers

Hi Jill, This is just the usual numerical 'error' due to the limitations of floating point arithmetic. std(.1*(ones(1,1e5)))...

2 months ago | 1

| accepted

Answered

Create block sparse matrix

HI ks, Here is one way. MODIFIED (see comment thread below) showing two possible methods to fill the matrix by means of a ...

Create block sparse matrix

HI ks, Here is one way. MODIFIED (see comment thread below) showing two possible methods to fill the matrix by means of a ...

2 months ago | 1

Answered

Flatten Matrix in Row Major Order in Arbitrary Dimensions

Hello Lucas-Raphael, I'm not sure this is what you are looking for, but B = permute(A,[6 5 4 3 2 1]); % (however many dim...

Flatten Matrix in Row Major Order in Arbitrary Dimensions

Hello Lucas-Raphael, I'm not sure this is what you are looking for, but B = permute(A,[6 5 4 3 2 1]); % (however many dim...

2 months ago | 0

Answered

Looking for a function f(x,y,z) based on 3 points to calculate interpolated/extrapolated values with a linear relation

HI Appli, This is something Matlab does really well. I assume by 'linear relation' you mean that each point has a value c = a...

Looking for a function f(x,y,z) based on 3 points to calculate interpolated/extrapolated values with a linear relation

HI Appli, This is something Matlab does really well. I assume by 'linear relation' you mean that each point has a value c = a...

2 months ago | 1

| accepted

Answered

Cannot plot Fourier Transform

Hi Reza, If you take a look at X, the result is X = -((pi*w*sign(w))/2 + fourier(cos(4*t)/t^2, t, w)/2)/pi^2 which shows tha...

Cannot plot Fourier Transform

Hi Reza, If you take a look at X, the result is X = -((pi*w*sign(w))/2 + fourier(cos(4*t)/t^2, t, w)/2)/pi^2 which shows tha...

2 months ago | 0