Python to MATLAB Help

Hello! We are trying to convert a python code to achieve the same result in matlab. This series of loops is written to compute the number of consecutive points from the center of a circle inside a specified radius. The number of points need to be counted both forward and backward in the original data from the center and also must be consecutive in the data. For example, points 68-82 should be counted as long as they fall within the radius around point 76, but if point 118 falls in the radius it should not be counted (it falls outside of the consecutive range).

Python code:

def dist(x1, y1, x2, y2):

return sqrt((x1-x2)**2 + (y1-y2)**2)

def SDC(r, l1, l2, i):

num_pts = 0

j = i

while j >= 0 and dist(l1[i], l2[i], l1[j], l2[j]) <= r:

num_pts += 1

j -= 1

j = i + 1

while j < len(l1) and dist(l1[i], l2[i], l1[j], l2[j]) <= r:

num_pts += 1

j += 1

return num_pts

R = 0.3

SDC_transform = list()

for ind in range(len(COPx)):

SDC_transform.append(SDC(R, COPx, COPy, ind))

We have tried using the sum function within loops in matlab that I have posted here, but the results are not the same.

nop = zeros(1,500);

radius = 0.3;

for ii = 1:500

j = ii;

Valueofnop = 0;

while ( (j >= 1) && (sqrt(((FPCOFx(ii) - FPCOFx(j))^2) + ((FPCOFy(ii) - FPCOFy(j))^2)) <= radius) )

x = FPCOFx - FPCOFx(ii);

y = FPCOFy - FPCOFy(ii);

Valueofnop = sum(x.^2 + y.^2 - radius^2 <0);

j = j-1;

end

j = ii + 1;

while ( (j <= 500) && (sqrt(((FPCOFx(ii) - FPCOFx(j))^2) + ((FPCOFy(ii) - FPCOFy(j))^2)) <= radius) )

x = FPCOFx - FPCOFx(ii);

y = FPCOFy - FPCOFy(ii);

Valueofnop = sum(x.^2 + y.^2 - radius^2 <0);

j = j + 1;

end

nop(ii) = Valueofnop;

end

Answer 1

[Jaswanth]

Hi Nina,

As an alternative to converting Python code to MATLAB, you can use Python code directly within MATLAB since MATLAB provides built-in support for calling Python functions.

Please refer to the following approach explaining how to call Python functions from MATLAB:

Ensure Python is Installed: Confirm that Python is installed on your system and that MATLAB is set up to utilize it.

Call Python Functions from MATLAB: You can directly call Python functions from MATLAB by using the py prefix. For example, if you have a Python function called my_function within a module named my_module, you can use:

result = py.my_module.my_function(arg1, arg2);

Use Python Libraries in MATLAB: You can leverage Python libraries directly in your MATLAB code. For example, to use the numpy library:

np = py.importlib.import_module('numpy');
array = np.array([1, 2, 3, 4]);

This approach allows you to take advantage of Python libraries and functionality without needing to rewrite code in MATLAB.

Kindly refer to the following MathWorks documentation on ‘Call Python from MATLAB’ discussed above: https://www.mathworks.com/help/matlab/call-python-libraries.html

I hope the solution provided above is helpful.