How can I apply the attached vector coding equation to a matrix in matlab?
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Kylie Davis
le 25 Mai 2016
Commenté : Star Strider
le 27 Mai 2016
I currently am using atan2d(y,x) but I am unsure whether that is accounting for the y(i+1)-y(i) and x(i+1)-x(i) nature of the equation. x and y are defined as the two matrices I am comparing (i.e. knee versus ankle joint angles during a gait cycle).
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Star Strider
le 25 Mai 2016
It won’t account for it unless you tell it to:
Theta_vc = atan2d(diff(theta1), diff(theta2));
NOTE — This should work with your data.
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Star Strider
le 27 Mai 2016
My code:
Theta_vc = atan2d(diff(theta1), diff(theta2));
does exactly what the expression in your image does. See the documentation on the diff function for details.
If you just have vectors, they will work with my code whether they’re row or column vectors. I don’t understand your gait cycle coding (an area peripheral to my areas of expertise). I would use atan2 or atan2d because they reflect the correct quadrants.
If you want to convert the angles you get as Theta_vc to 0°-360° or 0-2*pi, use the appropriate one of these functions:
Angles360 = @(a) rem(360+a, 360); % For ‘atan2d’
Angles2pi = @(a) rem(2*pi+a, 2*pi); % For ‘atan2’
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James Tursa
le 25 Mai 2016
Modifié(e) : James Tursa
le 25 Mai 2016
atan2d(y,x) will not do any difference calculations such as y(i+1)-y(i) or x(i+1)-x(i) as part of the calculation. So you would need to do that calculation before using atan2d (e.g. using the diff function). Are x and y 1D vectors or 2D matrices?
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