Slow simulation when using asind

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Eleni.T
Eleni.T on 11 Jun 2020
Commented: Eleni.T on 11 Jun 2020
hello!
I am trying t model a sun position algorithm in simulink and i used the embedded matlab function. My simulation time is 10*3600s. The function includes:
function [altitude, azimuth]= fcn(N, SL, LL, L, LST)
B=(N-81)*360/364;
ET=9.87*sind(2*B)-7.53*cosd(B)-1.5*sind(B);
AST=LST*60+ET+4*(SL-LL);
h=(AST/60-12)*15;
delta=(23.45*sind(360/365*(284+N)));
altitude=asind(sind(L)*sind(delta)+cosd(L)*cosd(delta)*cosd(h));
azimuth=asind(cosd(delta)*sind(h)/cosd(altitude));
However, when i use the 'asind' instead of 'asin' for the 'azimuth=asind(cosd(delta)*sind(h)/cosd(altitude))' equation, the simulation becomes extremely slow and i never get an answer. When i use asin I get an answer very quickly, though it is not correct since it is in radians instead of degrees. Does anyone know any potential reason for this extremely slow running?
Thank you
  2 Comments
darova
darova on 11 Jun 2020
you can convert radians to degree manually
a2 = a1*180/pi; % convert angle a1 (radius) to degrees
Eleni.T
Eleni.T on 11 Jun 2020
I tried that too but running is still very slow

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