In a message of Sun, 13 Sep 2015 07:49:37 -0700, sagar k writes: >Dear all > >I'm using Python 3.4.3. I am facing a problem in integrating using odeint >solver. In the following code, tran is a function and in those are the >variables which are arrays. These variables change their values with respect >to time (the time which I pass to the function). I tried defining a loop >inside the function, but Python throws an error saying float object not >iterable. Please guide me how to solve this problem. > >#initial is an array containing initial values for the integration, dt is the >time array with unequal time steps, which I have captured from other part of >the code > >def tran(initial,dt): > for i in dt: > k1 [i] = 2.8e8 * math.exp(-21100/ta[i]) # k1,k2,k3 & k4 are constants > which change according to temperature (ta), which in turn changes with > respect to time. > k2 [i] = 1.4e2 * math.exp(-12100/ta[i]) # ta changes its values > according to dt, which is array. It runs from 0-6 with unequal time steps. > k3 [i] = 1.4e5 * ta[i] * math.exp(-19680/ta[i]) # I've captured dt and > all other arrays here from another loop, which is not of importtance. > k4 [i] = 1.484e3 * ta[i] > y = initial[0] > z = initial[1] > dn = (6*rho*initial[1]) > dd = (math.pi*2000*initial[0]) > ds = (dn/dd)**1/3 > dydt = (166.2072*ta[i]*cca[i] - (1.447e13 * ta[i]**0.5 * rho**1/6 * > y**1/6 * rho**1/6 * z**1/6 * 0.0832)) # cca,ta are arrays. y & z are 2 > dependent variables > dzdt = (k1[i]*ta[i]*cca[i]*12.011 + (21.2834*k2[i]*ta[i]*cca[i] * > y**1/2 *ds) - (k3[i]*ta[i]*12.011*y*math.pi*ds**2 * cco[i]) - > (phi*k4[i]*ta[i]*xo[i]*12.011*y*math.pi*ds**2)) >return [dydt,dzdt] # dydt & dzdt are my final time integrated values > >initial = [0.01,1e-5] >sol = odeint(tran, initial, dt) #this is my function call > >If I pass array in my function call, it says only length-1 can be converted to >Python scalars. > >So I request all the experts in the group to tell me where I'm going wrong. > >Regards
You are getting this error, correct? TypeError: only length-1 arrays can be converted to Python scalars I don't know anything about odeint. But when I get these errors it is because I passed a numpy array into something that wanted a python list. This may be what you are doing. numpy arrays have a tolist method. see if passing array.tolist() instead of array works for you. Laura -- https://mail.python.org/mailman/listinfo/python-list
