Hey i kinda need help vectorizing the line below. Mod_normal is a scalar while P1, P2, P3, Prime are points in [xyz] format.

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Muhamad Amirulfaris Abdullah 2019-7-29

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https://ww2.mathworks.cn/matlabcentral/answers/473897-hey-i-kinda-need-help-vectorizing-the-line-below-mod_normal-is-a-scalar-while-p1-p2-p3-prime-are

回答： Maadhav Akula 2019-8-6

    V1 = P2 - prime; V2 = P3 - prime;
    alpha = norm(cross_product((V1), (V2)))/ ( Mod_normal);
    V1 = P3 - prime; V2 = P1 - prime;
    beta = norm(cross_product((V1), (V2)))/ ( Mod_normal);
    V1 = P1 - prime; V2 = P2 - prime;
    alpha2 = norm(cross_product((V1), (V2)))/ ( Mod_normal);
    gamma = 1 - alpha - beta;
    gamma2 = 1 - alpha2 - alpha;
    gamma3 = 1 - beta - alpha2;
    checklist = [alpha, beta,alpha2, gamma2,gamma3, gamma];

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Muhamad Amirulfaris Abdullah 2019-7-31

alt_2nd_newpointdistance3d.m

I think it would be easier if I give the code. I attached the code below. I was trying to speed up the code. BAsically the inputs of the function are Three vector points of xyz which is P1 P2 and P3. with P0 as testing pint. The function calculates the distance between point P0 and triangle P123. I was trying to code an alternate method besides David Eberly's pointtriangle distance code. I was wondering if there is any way which i can speed up the code

Muhamad Amirulfaris Abdullah 2019-7-31

cross_product.m

here is the link of the cross product function that i create instead of the built in function cross.

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Answer 1

Maadhav Akula 2019-8-6

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https://ww2.mathworks.cn/matlabcentral/answers/473897-hey-i-kinda-need-help-vectorizing-the-line-below-mod_normal-is-a-scalar-while-p1-p2-p3-prime-are#answer_386404

I think the code which you have provided runs pretty fast and only changes in your code would be to use the in-built functions such as cross, dot, norm to compute the cross-product, dot-product and magnitude of vectors respectively.

Hope this helps!