Answered

Conditional Random number generation

m = 5; n = 3; s = 10; This will generate uniform distribution with sum criteria % generate non-negative integer random (m x ...

Conditional Random number generation

m = 5; n = 3; s = 10; This will generate uniform distribution with sum criteria % generate non-negative integer random (m x ...

2 hours ago | 0

Answered

Rounded random numbers with fixed sum

k = 3; r = (diff([0 sort(randperm(100+k-1,k-1)) 100+k])-1)/100

Rounded random numbers with fixed sum

k = 3; r = (diff([0 sort(randperm(100+k-1,k-1)) 100+k])-1)/100

3 hours ago | 0

Answered

mex-file crashes MATLAB in for loop

Those are wrong, you should not Free the pointers that you are not Malloc. mxFree(a_double); mxFree(b_double); mxFree(z_do...

mex-file crashes MATLAB in for loop

Those are wrong, you should not Free the pointers that you are not Malloc. mxFree(a_double); mxFree(b_double); mxFree(z_do...

11 hours ago | 1

| accepted

Answered

C = union( A,B ) is too slow. Is there any faster way given that A and B are ordered.

If you have a decend C-compiler you might use my MEX MERGE SORTED ARRAY c = mergesa(a,b); % or mergemex(a,b); c = c([true; dif...

C = union( A,B ) is too slow. Is there any faster way given that A and B are ordered.

If you have a decend C-compiler you might use my MEX MERGE SORTED ARRAY c = mergesa(a,b); % or mergemex(a,b); c = c([true; dif...

12 hours ago | 1

Answered

Recover matrix Z from XZX', Z es symmetric and n-by-n, while X is k-by-n where n>>k

You can't getback to 27x27 covariance matrix Z after reducing it it on 5 dimensional space (by X). The information lost forevver...

Recover matrix Z from XZX', Z es symmetric and n-by-n, while X is k-by-n where n>>k

You can't getback to 27x27 covariance matrix Z after reducing it it on 5 dimensional space (by X). The information lost forevver...

1 day ago | 0

Answered

solve A*X=B containing very large or small elements

Work with unitless system, scale your matrix, or use automatic scaling if you don't want to bother.

solve A*X=B containing very large or small elements

Work with unitless system, scale your matrix, or use automatic scaling if you don't want to bother.

1 day ago | 0

Answered

How do I shift columns (left or right) in a matrix

k > 0 shift right k < 0 shift left A*diag(ones(1,size(A,2)-abs(k)),k)

How do I shift columns (left or right) in a matrix

k > 0 shift right k < 0 shift left A*diag(ones(1,size(A,2)-abs(k)),k)

1 day ago | 0

Answered

How to solve the equation of binary logic operation, where all unknowns are 0 or 1

[x1,x2,x3,x4,x5,x6]=ndgrid(0:1); x1 = x1(:); x2 = x2(:); x3 = x3(:); x4 = x4(:); x5 = x5(:); x6 = x6(:); b = [x1+x2+x3+...

How to solve the equation of binary logic operation, where all unknowns are 0 or 1

[x1,x2,x3,x4,x5,x6]=ndgrid(0:1); x1 = x1(:); x2 = x2(:); x3 = x3(:); x4 = x4(:); x5 = x5(:); x6 = x6(:); b = [x1+x2+x3+...

2 days ago | 0

Answered

Finding the most orthogonal set of n vectors from dataset of unit vectors

I propose this % random test A, which represents 100 normalized vector in R^5 n = 5; m = 100; A = randn(n,m); A = A ./ sqrt...

Finding the most orthogonal set of n vectors from dataset of unit vectors

I propose this % random test A, which represents 100 normalized vector in R^5 n = 5; m = 100; A = randn(n,m); A = A ./ sqrt...

2 days ago | 0

Answered

EVALIN cannot execute a return?

Yes it is written in the doc. From EVALIN/EVAL document page "evalin(workspace,expression) ... expression — Expression to ev...

EVALIN cannot execute a return?

Yes it is written in the doc. From EVALIN/EVAL document page "evalin(workspace,expression) ... expression — Expression to ev...

3 days ago | 1

| accepted

Answered

Matrix compare and unkonw relationships to find

Use regression methods. If you have a linear/affine model, then use linear algebra. If you have "kind" non-linear, use polynomia...

Matrix compare and unkonw relationships to find

Use regression methods. If you have a linear/affine model, then use linear algebra. If you have "kind" non-linear, use polynomia...

3 days ago | 0

Answered

Why is memory reduced for an identical copy of a sparse array?

Nah nothing to do with name length, it's the number of internal non zeros of ('Ir" and "Pr" old notation) array reserved by MATL...

Why is memory reduced for an identical copy of a sparse array?

Nah nothing to do with name length, it's the number of internal non zeros of ('Ir" and "Pr" old notation) array reserved by MATL...

3 days ago | 1

Answered

(Block-) Matrix multiplication inaccuracy

Same problem, don't count on exact associativity when working with floating point arithmetics. I can quote word-to-word from wha...

(Block-) Matrix multiplication inaccuracy

Same problem, don't count on exact associativity when working with floating point arithmetics. I can quote word-to-word from wha...

3 days ago | 0

Answered

Reshape n-th dimension of an array

You operation makes the array changing its size, you can't use for-loop to store the rotated page in the SAME arrray. And btw f...

Reshape n-th dimension of an array

You operation makes the array changing its size, you can't use for-loop to store the rotated page in the SAME arrray. And btw f...

3 days ago | 1

| accepted

Answered

Curl, Divergence calculation from velocity data

Your data is already gridded, no need to gridded on top of it load('matlab.mat') UU=reshape(data(:,3),[75 62]); VV=reshape(...

Curl, Divergence calculation from velocity data

Your data is already gridded, no need to gridded on top of it load('matlab.mat') UU=reshape(data(:,3),[75 62]); VV=reshape(...

3 days ago | 0

Answered

Checking a matrix for duplicates in specific row, removing the respective columns

d= [1 2 2 3 4 5 6 6 7; 1 2 3 4 5 6 7 7 8] dd = diff([nan,d(1,:),nan])==0; remove = dd(1:end-1) | dd(2:end) x_cut = uni...

Checking a matrix for duplicates in specific row, removing the respective columns

d= [1 2 2 3 4 5 6 6 7; 1 2 3 4 5 6 7 7 8] dd = diff([nan,d(1,:),nan])==0; remove = dd(1:end-1) | dd(2:end) x_cut = uni...

4 days ago | 0

| accepted

Answered

Interpolating at vertices of a mesh

In theory you cannot. A function that is piecewise constant on elements is discontinuos at the vertices and you cannot speak ab...

Interpolating at vertices of a mesh

In theory you cannot. A function that is piecewise constant on elements is discontinuos at the vertices and you cannot speak ab...

4 days ago | 0

Answered

Obtain the mean angle (circle mean of a file)

angledata_deg is your angle data in degree meanangle_deg = rad2deg(atan2(mean(sind(angledata_deg),2),mean(cosd(angledata_deg),2...

Obtain the mean angle (circle mean of a file)

angledata_deg is your angle data in degree meanangle_deg = rad2deg(atan2(mean(sind(angledata_deg),2),mean(cosd(angledata_deg),2...

5 days ago | 0

| accepted

Answered

How parentheses effects multiplication with pi ?

From wikipedia "While floating-point addition and multiplication are both commutative (a + b = b + a and a × b = b × a), they a...

How parentheses effects multiplication with pi ?

From wikipedia "While floating-point addition and multiplication are both commutative (a + b = b + a and a × b = b × a), they a...

5 days ago | 0

| accepted

Answered

Adding zeros to matrix

% Replace this with your image Image100 = peaks(100)+10; %Centering padding in 4 sides PadImage300 = zeros(300,300,size(Ima...

Adding zeros to matrix

% Replace this with your image Image100 = peaks(100)+10; %Centering padding in 4 sides PadImage300 = zeros(300,300,size(Ima...

5 days ago | 0

| accepted

Answered

How to create a surface with random spheres protruding?

Is this you want? x = linspace(0,1); y = linspace(0,1); [X,Y] = meshgrid(x,y); Z = zeros(size(X)); N = 30; for k=1:N ...

How to create a surface with random spheres protruding?

Is this you want? x = linspace(0,1); y = linspace(0,1); [X,Y] = meshgrid(x,y); Z = zeros(size(X)); N = 30; for k=1:N ...

5 days ago | 0

| accepted

Answered

Integral calculation using matlab

Feel free to change these hyper-parameters n = 3 k = 2*pi*rand() integral(@(phi) arrayfun(@(phi) abs(integral(@(theta) exp(...

Integral calculation using matlab

Feel free to change these hyper-parameters n = 3 k = 2*pi*rand() integral(@(phi) arrayfun(@(phi) abs(integral(@(theta) exp(...

6 days ago | 0

| accepted

Answered

Combining function handles into one function handle

a = @(x) x(1)^2+x(2)^2; b = @(x) x(3)^2-x(4)^2; c = @(x) x(1)*x(4); % suppose your for-loop puts each function handle in a ...

Combining function handles into one function handle

a = @(x) x(1)^2+x(2)^2; b = @(x) x(3)^2-x(4)^2; c = @(x) x(1)*x(4); % suppose your for-loop puts each function handle in a ...

6 days ago | 0

Answered

I cannot find the distance between two matrices with respect to the Frobenius inner product.

Distance in frobenius scalar product: dist_AB = norm(A - B, 'fro') which is the same as this norm(A(:)-B(:),2)

I cannot find the distance between two matrices with respect to the Frobenius inner product.

Distance in frobenius scalar product: dist_AB = norm(A - B, 'fro') which is the same as this norm(A(:)-B(:),2)

6 days ago | 0

| accepted

Answered

Indexing problem with matrices

A = [3 5 9 6 ; 2 1 13 6 ; 6 8 52 4 ; 13 6 8 22 ]; GRID = [linspace(1,100,100); rand(1,100); rand(1,100)]' Code [tf,loc]=ismem...

Indexing problem with matrices

A = [3 5 9 6 ; 2 1 13 6 ; 6 8 52 4 ; 13 6 8 22 ]; GRID = [linspace(1,100,100); rand(1,100); rand(1,100)]' Code [tf,loc]=ismem...

6 days ago | 0

| accepted

Answered

Convolution of to matrices

Example t1 = 0:2; A1 = [0.25 0.5 0.25]; t2 = [0 3 6]; A2 = [0.25 0.5 0.25]; Code for convolution vector Y (t,A) (I don't kn...

Convolution of to matrices

Example t1 = 0:2; A1 = [0.25 0.5 0.25]; t2 = [0 3 6]; A2 = [0.25 0.5 0.25]; Code for convolution vector Y (t,A) (I don't kn...

6 days ago | 0

| accepted

Answered

How do I turn of thr grid of a surface but keep the edge line on?

Just serve yourself with plot3 commands [X,Y,Z] = peaks; surf(X,Y,Z,'edgecolor','none'); hold on plot3(X(1,:),Y(1,:),Z(1,:),...

How do I turn of thr grid of a surface but keep the edge line on?

Just serve yourself with plot3 commands [X,Y,Z] = peaks; surf(X,Y,Z,'edgecolor','none'); hold on plot3(X(1,:),Y(1,:),Z(1,:),...

6 days ago | 1

Answered

Select points inside a polygon

Here is the code using POLYSHAPE load('Points.mat') load('polygon1_x.mat') load('polygon1_y.mat') lat = Points.lat; ...

Select points inside a polygon

Here is the code using POLYSHAPE load('Points.mat') load('polygon1_x.mat') load('polygon1_y.mat') lat = Points.lat; ...

6 days ago | 1

| accepted

Answered

Select points inside a polygon

But you already have the index in your code. here ... inon = in | on; % Combine .i...

Select points inside a polygon

But you already have the index in your code. here ... inon = in | on; % Combine .i...

6 days ago | 1

Answered

How to make a matrix of zeros and ones with a specific distance between each one?

dmin1=3; n=10; A=zeros(n); A(1:dmin1:end,1:dmin1:end)=1; disp(A)

How to make a matrix of zeros and ones with a specific distance between each one?

dmin1=3; n=10; A=zeros(n); A(1:dmin1:end,1:dmin1:end)=1; disp(A)

7 days ago | 0

| accepted