Hi everybody. I've been trying to solve some really huge matrix equations in matlab. But, every time, Matlab shows me, besides number and symbols, capital letter "I" or "PI" in a solution.
I need those equations later in other function for ODE45 solver. Ofcourse, ODE doesn't recognise "I" or "PI".
Here it is some sequance from the result:
1.0*(Kp3*x3 + Kv3*x6 + x11*(cos(- 2*x2 - 2/3*PI*(exp(-2*t^3) - 1)
I define Kp3, x3, Kv3 etc. as symbols, but I didn't mention anywhere "PI" or "I".
Does sombody know what is a problem here? And what should to avoide thise.
Thank you for helping me.
Thank you CaptainBlack. But "eval" doesn't work here. I tried. I don't know what the problem is. Sometimes, I get really wierd solution, worse then previous one. But that depends on how big equation is. Maybe there is some problem with ram memory, I don't know.
Real problem is simulation of one adaptive algoritham for 3DOF robot. When I put for desired trajectory, for instance, pi/3*sin(2*t)+3*cos(3*t), and something similar for other two joints, state space representation of the closed loop system is ok, without "I" or "PI", but the problem is for trajectory like pi/3*sin(2*t)+3*cos(3*t)*exp(2*t^3). The equation is too big for matlab command window so I had to use fprintf function. And in fprintf new file stands "I" or "PI", when I use pi instead 3.1416.
Once, I got, in the middle of equation some wierd string array, something like "msccd" or something. But, after restarting computer, remaind only "I" or "PI".
I don't have idea what can be a problem. But, of course, thank you again for helping me.