Help needed to vectorize this code

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Mehdi 2015-3-18

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https://ww2.mathworks.cn/matlabcentral/answers/183913-help-needed-to-vectorize-this-code

关闭： MATLAB Answer Bot 2021-8-20

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Hi everyone, I'm posting this for the second time so hopefully someone can help me with vectorizing my code. I have 3 for loops inside each other as seen here:

for A=1:a
    for B=1:b
        for C=1:c
                do_something (A,B,C)
        end
    end
end

Here is the actual code:

mpd_new = 8000;
mpr1    = 40000;
aicon    = 0.2;
mstr1    = 12000;
g0       = 9.81;
Irp1     = 317;
dt       = 0.1;
for mssf1 = 1370:1400;
    for t_i = 2:0.1:5;
        for alp_max = 1:0.1:4;
            t1       = 0;
            V1_X_cut = eps;
            V1_Z_cut = 0;
            ht1      = 0;
            pcg1     = 90;
            flp1     = 90;
            alp1     = 0;
            m_in1    = mstr1+mpr1+mpd_new;
            m_f1     = m_in1-mpr1;
            Mcrnt1   = m_in1-t1*mssf1;
            thst1     = mssf1*Irp1*g0;
            while Mcrnt1 > m_f1
                alp1     = -4*alp_max*Expon1*(1-Expon1);
                flp1     = atan(V1_Z_cut/V1_X_cut)*180/pi;
                pcg1     = flp1+alp1;
                pchrd1   = pcg1*pi/180;
                acc_z1   = thst1*sin(pchrd1)/Mcrnt1;
                acc_x1   = thst1*cos(pchrd1)/Mcrnt1;
                V1_X_cut = V1_X_cut+acc_x1*dt;
                V1_Z_cut = V1_Z_cut+acc_z1*dt;
                V_cr1    = sqrt(V1_X_cut^2 + V1_Z_cut^2);
                ht1      = ht1+V1_Z_cut*dt;
                Mcrnt1   = Mcrnt1-dt*mssf1;
                t1       = t1+dt;
            end
        end
    end
end

The problem is that it is extremely slow. I tried to vectorize it as seen below but it's not working properly:

mpd_new = 8000;
mpr1    = 40000;
aicon    = 0.2;
mstr1    = 12000;
g0       = 9.81;
Irp1     = 317;
dt       = 0.1;
mssf1 = 1370:1400;
t_i = 2:0.1:5;
alp_max = 1:0.1:4;
t1       = 0;
V1_X_cut = eps;
V1_Z_cut = 0;
ht1      = 0;
pcg1     = 90;
flp1     = 90;
alp1     = 0;
m_in1    = mstr1+mpr1+mpd_new;
m_f1     = m_in1-mpr1;
Mcrnt1   = m_in1-t1.*mssf1;
thst1     = mssf1.*Irp1.*g0;
while Mcrnt1 > m_f1
      Expon1   = exp(aicon.*(t_i-t1));
      alp1     = -4.*alp_max.*Expon1.*(1-Expon1);
      flp1     = atan(V1_Z_cut./V1_X_cut).*180./pi;
      pcg1     = flp1+alp1;
      pchrd1   = pcg1.*pi./180;
      acc_z1   = thst1.*sin(pchrd1)./Mcrnt1;
      acc_x1   = thst1.*cos(pchrd1)./Mcrnt1;
      V1_X_cut = V1_X_cut+acc_x1.*dt;
      V1_Z_cut = V1_Z_cut+acc_z1.*dt;
      V_cr1    = sqrt(V1_X_cut.^2 + V1_Z_cut.^2);
      ht1      = ht1+V1_Z_cut.*dt;
      Mcrnt1   = Mcrnt1-dt.*mssf1;
      t1       = t1+dt;
end