0 个投票

Hey everyone,
I'm running this equation
hMphi(1) = - (dd_Anis(1) * ddu_acos(1) * du_dMphi(1))/(C2*sin(Mtheta(1)))- ((Is*P_hbar/(2*P_Q*g*C2))*((ephix(1)*Ffx(1))+(ephiy(1)*Ffy(1))))- Ms*(Ny-Nx)*sin(Mtheta(1))*sin(2*Mphi(1))+ (Happy*cos(Mphi(1)) - Happx*sin(Mphi(1))) ;
in a loop and a certain point the value of this vector becomes a NAN?! Can Anyone tell me why is this happening? I' dividing by a sin, so I thought that maybe the problem is from it, but I printed the values of it I didn't get Inf.
Thanks

请先登录，再回答此问题。

 采纳的回答

Roger Stafford
Roger Stafford 2014-1-19

5 个投票

Any of these arithmetic operations will produce a NaN: zero/zero, zero*infinity, infinity/infinity, infinity-infinity. For example, if any of the three quantities, dd_Anis, ddu_acos, or du_dMph were to become zero at the same time that sin(Mtheta) is zero, that would produce a NaN. You should make a test on hMphi each time it is computed and arrange to stop if a NaN is detected so you can check all the values that go into your equation at that point.

更多回答（2 个）

Jan
Jan 2014-1-19

3 个投票

You can stop the code automatically, when the NaN appears:
dbstop if naninf
Then inspect the local variables and evaluate the different parts of the equation in the command window until you find the reason for the NaN.
Anna
Anna 2014-1-19

1 个投票

Have you tried to isolate the part of the equation where the fault is at? Debug the equation in the loop iteration before the equation turns into a NaN.

类别

在 帮助中心 和 File Exchange 中查找有关 Logical 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by