2,858 total contributions since 2007

Interested in external applications, mex & engine applications with Fortran, C, C++, etc, particularly in the areas of speed improvement and memory management efficiencies.

Answered

summation of sinx using summation

You are missing the alternating signs of the terms. E.g., you could put in a factor of (-1)^something to get this effect. The ...

summation of sinx using summation

You are missing the alternating signs of the terms. E.g., you could put in a factor of (-1)^something to get this effect. The ...

1 day ago | 0

Answered

How to concatenate each row of a matrix into a vector ?

result = char(A+'0');

How to concatenate each row of a matrix into a vector ?

result = char(A+'0');

1 day ago | 1

Answered

Index exceeds the number of array elements (1)

Type the following at the command line: dbstop if error Then run your code. When the error occurs, the code will pause at that...

Index exceeds the number of array elements (1)

Type the following at the command line: dbstop if error Then run your code. When the error occurs, the code will pause at that...

4 days ago | 0

Answered

How to correct "Parse" error

Don't have your function at the top of this. Put it at the end or in a separate file. E.g., t = 1; while (height ~=0) h =...

How to correct "Parse" error

Don't have your function at the top of this. Put it at the end or in a separate file. E.g., t = 1; while (height ~=0) h =...

8 days ago | 0

Answered

I have a matrix (57,3600,45), how can I create matrices with (3600,45)?

Is this what you want? k = some integer index squeeze(your_matrix(k,:,:))

I have a matrix (57,3600,45), how can I create matrices with (3600,45)?

Is this what you want? k = some integer index squeeze(your_matrix(k,:,:))

8 days ago | 0

Answered

Square root table without using arrays

You need to put the new line \n in appropriate places in your loops. In particular, you only need one new line \n printed once y...

Square root table without using arrays

You need to put the new line \n in appropriate places in your loops. In particular, you only need one new line \n printed once y...

8 days ago | 0

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Answered

Memory Size and Processor Speed

Yes you can run MATLAB on this. What tasks will you typically be using MATLAB for?

Memory Size and Processor Speed

Yes you can run MATLAB on this. What tasks will you typically be using MATLAB for?

10 days ago | 0

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Answered

How to? - Complex numbers

E.g., for an anonymous function you need to give the input argument list first. E.g., for a generic derivative function that tak...

How to? - Complex numbers

E.g., for an anonymous function you need to give the input argument list first. E.g., for a generic derivative function that tak...

12 days ago | 0

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Answered

And/or between two 3d arrays

Do you mean this? sum(array1>250 & array2>170,3);

And/or between two 3d arrays

Do you mean this? sum(array1>250 & array2>170,3);

12 days ago | 0

Answered

Function in Fortran to Funciton in Matlab

function result = F0(n,x) if( n<2 ) error('bad argument n in F0') end tox=2.0/x; bkm=F00(x); bk=F01(x); for j=1:n-1 ...

Function in Fortran to Funciton in Matlab

function result = F0(n,x) if( n<2 ) error('bad argument n in F0') end tox=2.0/x; bkm=F00(x); bk=F01(x); for j=1:n-1 ...

16 days ago | 1

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Answered

differentiating function & getting different answer

Perhaps you are shadowing the MATLAB function diff with a function of your own. Make sure diff is pointing to the MATLAB functio...

differentiating function & getting different answer

Perhaps you are shadowing the MATLAB function diff with a function of your own. Make sure diff is pointing to the MATLAB functio...

16 days ago | 0

Answered

Invalid Syntax at '='.Possibly,a ),} or ] is missing at line 6 .

The { } formulation for blocking code is not valid MATLAB syntax. To fix this: Get rid of the open brace { Replace the close b...

Invalid Syntax at '='.Possibly,a ),} or ] is missing at line 6 .

The { } formulation for blocking code is not valid MATLAB syntax. To fix this: Get rid of the open brace { Replace the close b...

17 days ago | 1

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Answered

use this vector and a mathematical expression to create the following vectors:

Yes. It works for me: >> x= [1, 2, 3, 4 ,5] x = 1 2 3 4 5 >> x1= x.*[1,128,243,64,5] x1 = 1 25...

use this vector and a mathematical expression to create the following vectors:

Yes. It works for me: >> x= [1, 2, 3, 4 ,5] x = 1 2 3 4 5 >> x1= x.*[1,128,243,64,5] x1 = 1 25...

22 days ago | 0

Answered

Extracting matrix values for an algorithm

Something like this? xy = your n x 2 array n = size(xy,1); for k=1:n % run your algorithm here with x = xy(k,1) and y = ...

Extracting matrix values for an algorithm

Something like this? xy = your n x 2 array n = size(xy,1); for k=1:n % run your algorithm here with x = xy(k,1) and y = ...

22 days ago | 1

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Answered

Basic power rule ((a^b)^c = a^(b*c)) does not work

This has been discussed in this forum before. Raising complex numbers to a power is a multi-valued operation. MATLAB picks one...

Basic power rule ((a^b)^c = a^(b*c)) does not work

This has been discussed in this forum before. Raising complex numbers to a power is a multi-valued operation. MATLAB picks one...

22 days ago | 1

Answered

Is it possible to use logical indexing to specify between a number interval and include a value outside that interval.

E.g., Mask = ismember(str,[' ','a':'z','A':'Z']); Or using your method Mask = (65<=Ustr & Ustr<=90) | Ustr == 32;

Is it possible to use logical indexing to specify between a number interval and include a value outside that interval.

E.g., Mask = ismember(str,[' ','a':'z','A':'Z']); Or using your method Mask = (65<=Ustr & Ustr<=90) | Ustr == 32;

23 days ago | 1

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Answered

BEGINNER PROBLEM: Trying to finish up an assignment but I am stuck with this error and am not sure how to fix

lab_total and assign_total and exam_total are all vectors, so the right hand side expression is a vector. You try to stuff that...

BEGINNER PROBLEM: Trying to finish up an assignment but I am stuck with this error and am not sure how to fix

lab_total and assign_total and exam_total are all vectors, so the right hand side expression is a vector. You try to stuff that...

24 days ago | 1

Answered

I have a problem with this ode45

I don't see anywhere in your code where you define i and j before using them as indexes into Phi0 and Z0, so they default to the...

I have a problem with this ode45

I don't see anywhere in your code where you define i and j before using them as indexes into Phi0 and Z0, so they default to the...

24 days ago | 0

Answered

Vector matrix multiplication with a condition

For later versions of MATLAB: c = all(A==B | A==2,2); For earlier versions: c = all(bsxfun(@eq,A,B) | A==2,2);

Vector matrix multiplication with a condition

For later versions of MATLAB: c = all(A==B | A==2,2); For earlier versions: c = all(bsxfun(@eq,A,B) | A==2,2);

24 days ago | 0

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Answered

Can ode45 solve a ODE with space dependent parameters?

Yes. In general, if the derivative is a function of current state and time (even if there are vectors or matrices involved), the...

Can ode45 solve a ODE with space dependent parameters?

Yes. In general, if the derivative is a function of current state and time (even if there are vectors or matrices involved), the...

26 days ago | 2

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Answered

Is it possible to set rules for calculating permutations of column vectors?

Use the diff( ) function to calculate all of the permutations, and then count the number of valid ones. E.g., P = perms(1:i...

Is it possible to set rules for calculating permutations of column vectors?

Use the diff( ) function to calculate all of the permutations, and then count the number of valid ones. E.g., P = perms(1:i...

26 days ago | 1

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Answered

Get UNIX standard timestamp on MATLAB

You need to be careful about how you use the posixtime(t) function. From the documentation: "...If the time zone of t is not sp...

Get UNIX standard timestamp on MATLAB

You need to be careful about how you use the posixtime(t) function. From the documentation: "...If the time zone of t is not sp...

2 months ago | 2

Answered

How can I determine the angle between two vectors in MATLAB?

This topic has been discussed many times on the Newsgroup forum ... if I looked hard enough I'm sure I could find several Roger ...

How can I determine the angle between two vectors in MATLAB?

This topic has been discussed many times on the Newsgroup forum ... if I looked hard enough I'm sure I could find several Roger ...

2 months ago | 3

Answered

"To RESHAPE the number of elements must not change".This error occurs in line18.how to correct this error?

This expression is only going to work if size(a,1)*size(a,1) = numel(a): reshape(a,size(a,1),size(a,1),1); What are you trying...

"To RESHAPE the number of elements must not change".This error occurs in line18.how to correct this error?

This expression is only going to work if size(a,1)*size(a,1) = numel(a): reshape(a,size(a,1),size(a,1),1); What are you trying...

2 months ago | 0

Answered

Matlab crashes but Octave doesn't

What happens if you do the A\b differently? E.g., doing the LU decomposition manually and then backsolving yourself? Or doing pi...

Matlab crashes but Octave doesn't

What happens if you do the A\b differently? E.g., doing the LU decomposition manually and then backsolving yourself? Or doing pi...

2 months ago | 0

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Answered

R2018b real times complex multiplication

Probably related to the fact that complex variables changed to an interleaved storage format in R2018a. So my guess is this is w...

R2018b real times complex multiplication

Probably related to the fact that complex variables changed to an interleaved storage format in R2018a. So my guess is this is w...

2 months ago | 2

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Answered

Write a function called WordProduct to calculate the alphabetic word product of a character vector.

Hints to get you started: Look at the upper( ) and lower( ) functions What happens if you subract 'a' or 'A' from your vector?...

Write a function called WordProduct to calculate the alphabetic word product of a character vector.

Hints to get you started: Look at the upper( ) and lower( ) functions What happens if you subract 'a' or 'A' from your vector?...

2 months ago | 0

Answered

Changing elements with a condition

clear X2 X3 [m,n] = size(X1); X2(2:m,2:n) = X1(1:m-1,1:n-1); X3(3:m,3:n) = X1(1:m-2,1:n-2);

Changing elements with a condition

clear X2 X3 [m,n] = size(X1); X2(2:m,2:n) = X1(1:m-1,1:n-1); X3(3:m,3:n) = X1(1:m-2,1:n-2);

2 months ago | 1

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Answered

I dont understand the vectors and element parts.

Typo. This j*y*(1) <-- Uses the full vector y times the scalar 1 should be this j*y(1) <-- Uses only the y(1) element

I dont understand the vectors and element parts.

Typo. This j*y*(1) <-- Uses the full vector y times the scalar 1 should be this j*y(1) <-- Uses only the y(1) element

2 months ago | 0

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Answered

Efficient indexing with nested object and object arrays

Whether this works or not depends on what is in the properties, but have you tried simple concatenation on the rhs? [out] = [pa...

Efficient indexing with nested object and object arrays

Whether this works or not depends on what is in the properties, but have you tried simple concatenation on the rhs? [out] = [pa...

2 months ago | 0