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

Answered

Wrapper to run 32-Bit mex files on 64-Bit MATLAB

32-bit mex files are not standalone code. They interact with 32-bit MATLAB library code which interacts with the 32-bit MATLAB ...

Wrapper to run 32-Bit mex files on 64-Bit MATLAB

32-bit mex files are not standalone code. They interact with 32-bit MATLAB library code which interacts with the 32-bit MATLAB ...

1 hour ago | 0

Answered

Taylor series for sin(x) doesn't give the right answer above 34 radians

The larger x is, the more cancellation error you are going to get with the intermediate sums. It would be best to reduce the ra...

Taylor series for sin(x) doesn't give the right answer above 34 radians

The larger x is, the more cancellation error you are going to get with the intermediate sums. It would be best to reduce the ra...

13 hours ago | 0

Answered

code for eulers method help

This needs to be outside of and prior to your loop, and r needs a multiply operator: f=@(y)r*(1-(y/L))*y-((p*y^2)/(q+y^2)); Th...

code for eulers method help

This needs to be outside of and prior to your loop, and r needs a multiply operator: f=@(y)r*(1-(y/L))*y-((p*y^2)/(q+y^2)); Th...

21 hours ago | 1

Answered

minutes to hour and minutes

Make mins a column vector, or use mins(:) in your function handle.

minutes to hour and minutes

Make mins a column vector, or use mins(:) in your function handle.

1 day ago | 0

Answered

syntax error using complex loops

Did you mean while c <= 19 For loops should be looping over a fixed number of iterations, not a logical condition. While loop...

syntax error using complex loops

Did you mean while c <= 19 For loops should be looping over a fixed number of iterations, not a logical condition. While loop...

2 days ago | 0

Answered

Create Array that reorders given values to have smallest first and largest last while maintaining the rest of the array.

That 2nd loop needs to run in reverse order. You need to bubble that smallest number which might be near the back all the way t...

Create Array that reorders given values to have smallest first and largest last while maintaining the rest of the array.

That 2nd loop needs to run in reverse order. You need to bubble that smallest number which might be near the back all the way t...

2 days ago | 0

Answered

Need helping creating and solving for this equation: f(t)=4- t^2 e^(-3t)

Here is a basic outline to get you started: n = 100; % Number of elements t = zeros( you fill this in ); % create an t vector ...

Need helping creating and solving for this equation: f(t)=4- t^2 e^(-3t)

Here is a basic outline to get you started: n = 100; % Number of elements t = zeros( you fill this in ); % create an t vector ...

4 days ago | 0

Answered

How can I use a for loop to create new variables?

You might consider automatic array expansion. E.g., look at this result: t = 0:0.01:10; % row a = [0.1 1 3]'; % column y = e...

How can I use a for loop to create new variables?

You might consider automatic array expansion. E.g., look at this result: t = 0:0.01:10; % row a = [0.1 1 3]'; % column y = e...

7 days ago | 1

Answered

Can someone convert this to matlab code?

So, you don't need any loops for this. Just use the automatic array expansion feature. E.g., take a look at what happens with ...

Can someone convert this to matlab code?

So, you don't need any loops for this. Just use the automatic array expansion feature. E.g., take a look at what happens with ...

7 days ago | 0

Answered

Two variables need to be connected to one struct variable.

What about something like this: Results.First_Name = first_name{target}; Results.Last_Name = last_name{target}:

Two variables need to be connected to one struct variable.

What about something like this: Results.First_Name = first_name{target}; Results.Last_Name = last_name{target}:

7 days ago | 0

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Answered

How would I write the function of f(x)=sin(x)*exp(-x/10)

The multiply. E.g., f = @(x) sin(x) .* exp(-x/10); You don't need it on the divide because you are dividing by a scalar.

How would I write the function of f(x)=sin(x)*exp(-x/10)

The multiply. E.g., f = @(x) sin(x) .* exp(-x/10); You don't need it on the divide because you are dividing by a scalar.

7 days ago | 1

Answered

Error using ^ (line 51) Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

This is often caused by using a matrix or vector in an equation when you thought you were using a scalar. E.g., take these lines...

Error using ^ (line 51) Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

This is often caused by using a matrix or vector in an equation when you thought you were using a scalar. E.g., take these lines...

7 days ago | 0

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Answered

Reading 64 bit words

Try reading and keeping the type as uint64 (using the *) instead of converting to double: word = fread(fid,1,'*uint64');

Reading 64 bit words

Try reading and keeping the type as uint64 (using the *) instead of converting to double: word = fread(fid,1,'*uint64');

7 days ago | 0

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Answered

mex, error C3861: "mxGetDoubles": Cannot find the identifier, "mxGetUint8s": Cannot find the identifier ？

Those functions are for the R2018a memory model API. For that, you need to add the -R2018a option flag: mex myfile.cpp -R2018a...

mex, error C3861: "mxGetDoubles": Cannot find the identifier, "mxGetUint8s": Cannot find the identifier ？

Those functions are for the R2018a memory model API. For that, you need to add the -R2018a option flag: mex myfile.cpp -R2018a...

8 days ago | 0

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Answered

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

You are missing an ending parenthesis, and also you probably need to use element-wise multiply: u3 = exp(-0.89*t) .* (1.75*cos(...

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

You are missing an ending parenthesis, and also you probably need to use element-wise multiply: u3 = exp(-0.89*t) .* (1.75*cos(...

8 days ago | 0

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Answered

Solving a nonlinear ODE

Step 1: Solve your ODE for the highest order derivative, in this case Rdoubledot (on paper) Rdoubledot = stuff (you figure thi...

Solving a nonlinear ODE

Step 1: Solve your ODE for the highest order derivative, in this case Rdoubledot (on paper) Rdoubledot = stuff (you figure thi...

11 days ago | 0

Answered

Computational Complexity of matrix multiplication

This question is perhaps more involved than it looks on the surface, because by default MATLAB doesn't store the imaginary part ...

Computational Complexity of matrix multiplication

This question is perhaps more involved than it looks on the surface, because by default MATLAB doesn't store the imaginary part ...

11 days ago | 0

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Answered

error:All functions in a script must be closed with an 'end'.( kindly see the code and help me to remove the error)

Looks like maybe this for iy = 1:H end for ix = 1:W should be just this for iy = 1:H for ix = 1:W Side Note: This would b...

error:All functions in a script must be closed with an 'end'.( kindly see the code and help me to remove the error)

Looks like maybe this for iy = 1:H end for ix = 1:W should be just this for iy = 1:H for ix = 1:W Side Note: This would b...

12 days ago | 0

Answered

Using the euler method

p(ip) is the value of p at time t(ip). p isn't a function that you are passing time into like you are doing with p(t(ip)). So ...

Using the euler method

p(ip) is the value of p at time t(ip). p isn't a function that you are passing time into like you are doing with p(t(ip)). So ...

16 days ago | 0

Answered

Finding Nonzero Elements in a Vector

You need to wrap this statement with an if-test and only execute it if v(CurrentPosition) is non-zero: prod = prod * v(CurrentP...

Finding Nonzero Elements in a Vector

You need to wrap this statement with an if-test and only execute it if v(CurrentPosition) is non-zero: prod = prod * v(CurrentP...

16 days ago | 0

Answered

Markov Chain probability steady state

Hint: The probability of moving from one state to another state in n steps is P^n

Markov Chain probability steady state

Hint: The probability of moving from one state to another state in n steps is P^n

19 days ago | 0

Answered

Factorial without the Command

You could use either use a loop to multiply all of the numbers from 1 to n, or use recursion to multiply n by the factorial of n...

Factorial without the Command

You could use either use a loop to multiply all of the numbers from 1 to n, or use recursion to multiply n by the factorial of n...

20 days ago | 0

Answered

Inputs a Vector and Returns the Second Smallest Element

Your algorithm always replaces Smallest and SecondSmallest at each iteration. Does that make sense? E.g., if the current Smalle...

Inputs a Vector and Returns the Second Smallest Element

Your algorithm always replaces Smallest and SecondSmallest at each iteration. Does that make sense? E.g., if the current Smalle...

20 days ago | 0

Answered

Hex to float like python struct.unpack()

Could be a Big Endian vs Little Endian thing. E.g., inserting a swapbytes( ) step: >> hex = 'C956F53D' hex = 'C956F53D' ...

Hex to float like python struct.unpack()

Could be a Big Endian vs Little Endian thing. E.g., inserting a swapbytes( ) step: >> hex = 'C956F53D' hex = 'C956F53D' ...

20 days ago | 0

Answered

Python to MATLAB accuracy

Probably not. The trailing bits of floating point calculations in general can't be trusted. It you change the order of the calc...

Python to MATLAB accuracy

Probably not. The trailing bits of floating point calculations in general can't be trusted. It you change the order of the calc...

20 days ago | 0

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Answered

solving coefficient with linear algebra

You basically have this: [ONES_COLUMN, X_COLUMN, Y_COLUMN] * p = DATA You know all the CAPS stuff. So just use the standard l...

solving coefficient with linear algebra

You basically have this: [ONES_COLUMN, X_COLUMN, Y_COLUMN] * p = DATA You know all the CAPS stuff. So just use the standard l...

22 days ago | 0

Answered

Composite Functions with a function with two ranges

For example, take the first one: (g o f)(x) This is just g(f(x)) which is g(x^2) Assuming we are talking only about real in...

Composite Functions with a function with two ranges

For example, take the first one: (g o f)(x) This is just g(f(x)) which is g(x^2) Assuming we are talking only about real in...

26 days ago | 0

Answered

im trying to create a while loop for random numbers and it says if its even or odd

Change this while times < 20 to this while Ecounter < 20 and change this Ecounter = 0+1; to this ...

im trying to create a while loop for random numbers and it says if its even or odd

Change this while times < 20 to this while Ecounter < 20 and change this Ecounter = 0+1; to this ...

27 days ago | 0

Answered

The Body Mass Index, or BMI

Just get rid of these lines: function BMI=findbmi(Weight,Height)

The Body Mass Index, or BMI

Just get rid of these lines: function BMI=findbmi(Weight,Height)

27 days ago | 1