Answered

Corrcoef of two variables of unequal lengths

Mathworks states in their description of corrcoef, "R = corrcoef(X) returns a matrix R of correlation coefficients calculated ...

Corrcoef of two variables of unequal lengths

Mathworks states in their description of corrcoef, "R = corrcoef(X) returns a matrix R of correlation coefficients calculated ...

7 months ago | 0

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Answered

How to plot an Ellipse

Let (x1,y1) and (x2,y2) be the coordinates of the two vertices of the ellipse's major axis, and let e be its eccentricity. a =...

How to plot an Ellipse

Let (x1,y1) and (x2,y2) be the coordinates of the two vertices of the ellipse's major axis, and let e be its eccentricity. a =...

1 year ago | 4

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Answered

Eigenvectors are not orthogonal for some skew-symmetric matrices, why?

Your matrix A is _"defective"_ , meaning that its eigenvalues are not all distinct. In fact, it has only three distinct eigenva...

Eigenvectors are not orthogonal for some skew-symmetric matrices, why?

Your matrix A is _"defective"_ , meaning that its eigenvalues are not all distinct. In fact, it has only three distinct eigenva...

2 years ago | 1

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Answered

Sum of highest length of consecutive lowest values from a array.

L = min(A); f = find(diff([false,A==L,false])~=0); h = L*max(f(2:2:end)-f(1:2:end-1)); h is the highest sum of consec...

Sum of highest length of consecutive lowest values from a array.

L = min(A); f = find(diff([false,A==L,false])~=0); h = L*max(f(2:2:end)-f(1:2:end-1)); h is the highest sum of consec...

2 years ago | 0

Answered

What condition to use for checking whether at least a single negative element in a array?

Use the 'any' logical function. if any(A.*B<0) If you are dealing with an array, C, of more than one dimension, do this:...

What condition to use for checking whether at least a single negative element in a array?

Use the 'any' logical function. if any(A.*B<0) If you are dealing with an array, C, of more than one dimension, do this:...

2 years ago | 0

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Answered

How to Make a Matrix Diagonal with Matlab?

Call on Matlab's 'svd' function. Read about it at: https://www.mathworks.com/help/matlab/ref/svd.html or possible you n...

How to Make a Matrix Diagonal with Matlab?

Call on Matlab's 'svd' function. Read about it at: https://www.mathworks.com/help/matlab/ref/svd.html or possible you n...

2 years ago | 0

Answered

Finding if a vector is a subset

The following should be faster: m = size(a,2); n = size(b,2); for k = 1:n-m+1 s = all(a==b(k:k+m-1)); if s,...

Finding if a vector is a subset

The following should be faster: m = size(a,2); n = size(b,2); for k = 1:n-m+1 s = all(a==b(k:k+m-1)); if s,...

2 years ago | 0

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Answered

How to plot level curves of f(x,y) = 2x^2 + 5y^2. f(x,y) = c for c = 1,2,3,4,5,6

Your "level" curves are all ellipses and can most easily be generated by: t = linspace(0,2*pi); x = sqrt(c/2)*cos(t); ...

How to plot level curves of f(x,y) = 2x^2 + 5y^2. f(x,y) = c for c = 1,2,3,4,5,6

Your "level" curves are all ellipses and can most easily be generated by: t = linspace(0,2*pi); x = sqrt(c/2)*cos(t); ...

2 years ago | 0

Answered

how to make a function (named pcc ) that solves the cartesian product of 2 strings A(with n elements) and B(with m elements)?

Assume A and B are row strings. C = [reshape(repmat(A,length(B),1),[],1),repmat(B(:),length(A),1)]; The two-element rows...

how to make a function (named pcc ) that solves the cartesian product of 2 strings A(with n elements) and B(with m elements)?

Assume A and B are row strings. C = [reshape(repmat(A,length(B),1),[],1),repmat(B(:),length(A),1)]; The two-element rows...

2 years ago | 0

Answered

how to create function half adder in matlab

If the input bits are numeric scalars or logical values, b1 and b2, then the sum bit, 's', would be: s = b1 xor b2; or e...

how to create function half adder in matlab

If the input bits are numeric scalars or logical values, b1 and b2, then the sum bit, 's', would be: s = b1 xor b2; or e...

2 years ago | 0

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Answered

Using nested loops, write a Matlab program that goes through all elements of a matrix (2D array) and replaces every element that is either a multiple of 5 or 7 with -1.

Your test on a number x from your array can be: if round(x/5)==x/5 | round(x/7)==x/7 (Doing fprintf('-1') just prints ou...

Using nested loops, write a Matlab program that goes through all elements of a matrix (2D array) and replaces every element that is either a multiple of 5 or 7 with -1.

Your test on a number x from your array can be: if round(x/5)==x/5 | round(x/7)==x/7 (Doing fprintf('-1') just prints ou...

2 years ago | 0

Answered

What is the output?

The vector x has only three elements, [0,.3,.6], so the 'for' instruction reads: for n = 4:2 Therefore the loop will not...

What is the output?

The vector x has only three elements, [0,.3,.6], so the 'for' instruction reads: for n = 4:2 Therefore the loop will not...

2 years ago | 0

Answered

Please help me convert equation to matlab code.

N = 100; % <-- Choose some large number s = x; for n = 2*N-1:-2:1 s = x - s*x^2/((n+2)*(n+1)); end (I t...

Please help me convert equation to matlab code.

N = 100; % <-- Choose some large number s = x; for n = 2*N-1:-2:1 s = x - s*x^2/((n+2)*(n+1)); end (I t...

2 years ago | 0

Answered

Why am I getting Inf in my matrix

It is easily possible for two finite nonzero numbers to have a quotient so large that Matlab must give 'inf' as its value. For ...

Why am I getting Inf in my matrix

It is easily possible for two finite nonzero numbers to have a quotient so large that Matlab must give 'inf' as its value. For ...

2 years ago | 1

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Answered

Multiply a column by a number

Let Ar be the name of the array. Ar(:,6) = 4*Ar(:,6); What could be simpler? Since 4 is a scalar, it is automatically a...

Multiply a column by a number

Let Ar be the name of the array. Ar(:,6) = 4*Ar(:,6); What could be simpler? Since 4 is a scalar, it is automatically a...

2 years ago | 0

Answered

how to use nested for loop by grabbing one column and subtracting another column.

Your n value will be 1478, but in z(i,j+1) you have allowed the j+1 index to get as large as 1479 because you have "for j=1:1:n"...

how to use nested for loop by grabbing one column and subtracting another column.

Your n value will be 1478, but in z(i,j+1) you have allowed the j+1 index to get as large as 1479 because you have "for j=1:1:n"...

2 years ago | 0

Answered

Why does y come out as one number?

The scalar result is caused by the use of matrix division rather than element-by-element division. Replace '/' by './'. Simila...

Why does y come out as one number?

The scalar result is caused by the use of matrix division rather than element-by-element division. Replace '/' by './'. Simila...

2 years ago | 0

Answered

Lagrange Interpolation code error

The message is caused by your not defining or properly entering the value of vector 'xi'.

Lagrange Interpolation code error

The message is caused by your not defining or properly entering the value of vector 'xi'.

2 years ago | 0

Answered

Trapezoidal rule to find total work?

I would think your code should be this: work = 0; for k = 2:length(t) work = work + (F(k)+F(k-1))/2*(v(k-1)+v(k))/2...

Trapezoidal rule to find total work?

I would think your code should be this: work = 0; for k = 2:length(t) work = work + (F(k)+F(k-1))/2*(v(k-1)+v(k))/2...

2 years ago | 0

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Answered

How to do polynomial differentiation

Let P be the usual Matlab row vector of coefficients of a polynomial. Then, (as we all learned in calculus,) the corresponding ...

How to do polynomial differentiation

Let P be the usual Matlab row vector of coefficients of a polynomial. Then, (as we all learned in calculus,) the corresponding ...

2 years ago | 1

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Answered

convert two column matrices into one column matrix

In the example you gave do this: C = zeros(9,1); C(1:2:end) = A; C(2:2:end) = B; For a general answer you need to ...

convert two column matrices into one column matrix

In the example you gave do this: C = zeros(9,1); C(1:2:end) = A; C(2:2:end) = B; For a general answer you need to ...

2 years ago | 0

Answered

Does 'i' after value stand for 'index', and if so why does it appear as part of the answer?

The 'i' in your result indicates a complex answer. I assume you are familiar with complex numbers. The 'i' represents the squa...

Does 'i' after value stand for 'index', and if so why does it appear as part of the answer?

The 'i' in your result indicates a complex answer. I assume you are familiar with complex numbers. The 'i' represents the squa...

2 years ago | 1

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Answered

Representing base 4 numbers as "random walks"

The Matlab function 'dec2base' can be used to covert integers to character strings involving the characters '0', '1', '2', and '...

Representing base 4 numbers as "random walks"

The Matlab function 'dec2base' can be used to covert integers to character strings involving the characters '0', '1', '2', and '...

2 years ago | 0

Answered

How to generate a joint probability matrix from a data matrix

Call the data matrix D. Then the two columns of D(:,2:3) are X and Y. XY = sortrows(D(:,2:3)); F = find( [true,any(XY(1...

How to generate a joint probability matrix from a data matrix

Call the data matrix D. Then the two columns of D(:,2:3) are X and Y. XY = sortrows(D(:,2:3)); F = find( [true,any(XY(1...

2 years ago | 0

Answered

How can I write a program that indicates a number if it is integer or not?

If n is your number, then round(n)==n is true if and only if n is an integer

How can I write a program that indicates a number if it is integer or not?

If n is your number, then round(n)==n is true if and only if n is an integer

2 years ago | 0

Answered

where can i use round function to make the function perfect

I would suggest initially multiplying both 'tendered' and 'price' by 100 and using 'round' on the result: tendered = round(...

where can i use round function to make the function perfect

I would suggest initially multiplying both 'tendered' and 'price' by 100 and using 'round' on the result: tendered = round(...

2 years ago | 0

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Answered

if a & b

You can't use the "short circuit" forms of logical operations for operands other than scalars. The double symbol '&&' is the sh...

if a & b

You can't use the "short circuit" forms of logical operations for operands other than scalars. The double symbol '&&' is the sh...

2 years ago | 1

Answered

How do I use an matrix of indices to reference values in another matrix without using a loop?

[a,b,c] = size(alltemps); % tempindex must be 1 x b x c savedtemp = reshape(alltemps(reshape(tempindex,1,[])+(0:a:a*(b*c-1...

How do I use an matrix of indices to reference values in another matrix without using a loop?

[a,b,c] = size(alltemps); % tempindex must be 1 x b x c savedtemp = reshape(alltemps(reshape(tempindex,1,[])+(0:a:a*(b*c-1...

2 years ago | 0

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Answered

Solving a system of integral equations numerically

@Lewis: I noticed that the integrands in both of your integrals become infinite at the upper limit of integration, and this can ...

Solving a system of integral equations numerically

@Lewis: I noticed that the integrands in both of your integrals become infinite at the upper limit of integration, and this can ...

2 years ago | 0

Answered

Solving a system of integral equations numerically

This is a problem you can solve using Matlab's 'fsolve' function. The fact that your objective function requires two numerical ...

Solving a system of integral equations numerically

This is a problem you can solve using Matlab's 'fsolve' function. The fact that your objective function requires two numerical ...

2 years ago | 0