MATLAB: How to speed up the calculation time for the “rpmtrack” function

10e410e5computationinputr2018arpmtrackSignal Processing Toolboxspeedtimevector

I am using the "rpmtrack" function in the MATLAB R2018a prerelease. When my "x" signal input has ~ 10e5 elements, the "rpmtrack" function takes 15 minutes to run. If my "x" input signal has ~ 10e4 elements, it only takes a couple minutes to run. Is there any way I can decrease the run time of this function when inputting a vector with 10e5 elements?

Best Answer

There are a couple methods of speeding up the computation time of the "rpmTrack" function:

Divide the signal into various segments. Then, estimate the rpm over each segment, and concatenate those rpm estimates.
Coarsen the frequency resolution to reduce FFT length, and then compensate the ridge estimation accuracy by specifying enough ridge points and penalty values. This can be done using the name-value pairs for this function such as "FrequencyResolution" and "FrequencyPenalty", as pointed out in the function's documentation page.

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MATLAB: How to obtain the coordinates of the mouse on the screen displayed somewhere in the figure window

This enhancement has been incorporated in MATLAB 7.5 (R2007b).

As a workaround in previous MATLAB releases, you can use the following MATLAB function to track mouse motion:

function mousetrk
%MOUSETRK function to track mouse motion
% This function creates two static text controls
% which contain the x & y coordinates of the mouse
% The driving callback is executed by the
% WindowButtonMotionFcn of the figure.
figure
axes('Visible','off')
xbox = uicontrol('Style','text','Tag','xbox');
xboxlabel = uicontrol('Style','text','String','X Value',...
    'Position',get(xbox,'position')+[0 21 0 0]);
ybox = uicontrol('Style','text','Position',[90 20 60 20],'Tag','ybox');
yboxlabel = uicontrol('Style','text','String','Y Value',...
    'Position',get(ybox,'position')+[0 21 0 0]);
callback = ['pt = get(gca,''CurrentPoint'');'...
  'xbox = findobj(''Tag'',''xbox'');' ...
  'ybox = findobj(''Tag'',''ybox'');' ...
  'set(xbox,''String'',num2str(pt(1,1)));' ...
  'set(ybox,''String'',num2str(pt(1,2)));'];
set(gcf,'WindowButtonMotionFcn',callback);

For more information on the WindowButton functions, please refer to the Handle Graphics Property Browser:

https://www.mathworks.com/help/releases/R2009b/techdoc/infotool/hgprop/doc_frame.html

MATLAB: How to use Excellink functions in a Excel Macro Function instead of a Sub

The above Macro Subroutine can be translated to the following Macro Function:

Function Calculate(A As Range, b As Range) As Variant
    MLOpen
    MLPutMatrix "A", A
    MLPutMatrix "b", b
    MLEvalString "x = myfunc(A, b)"
    MLGetVar "x", Calculate
End Function

The inputs to MLPutMatrix are Ranges. MLGetVar is used to write the "x" from the MATLAB workspace to the "Calculate" variable.

Note Excel Macro Functions only support one output range. For MATLAB functions with multiple outputs, consider writing to multiple ranges directly.

      MLGetMatrix "x", "x"
      MLGetMatrix "y", "y"

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MATLAB: How to obtain the coordinates of the mouse on the screen displayed somewhere in the figure window

MATLAB: How to use Excellink functions in a Excel Macro Function instead of a Sub

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