Method of Runge-Kutta in Python -

-

i wrote code runge-kutta method in python, every time when program realizes calculus program require differential equation.

this code:

from math import * import numpy np  #initial values n=input("enter number of equations n:") n=int(n) x=np.array([]) in range(0,n):     x0=input("enter initial value of x{}:".format(i))     x=np.append(x,[x0]) t=input("enter initial value of t:") tf=input("enter final value of t:") h=input("enter time interval h:") m=int((tf-t)/float(h))  #definition of differential equations def f(t,x):     f=np.array([])     in range(0,n):         f0=input("enter equation f{}:".format(i))         f=np.append(f,[f0])     return f   a=1.0/6 in range(0,m):      k1=f(t,x)     k2=f(t+0.5*h,x+0.5*h*k1)     k3=f(t+0.5*h,x+0.5*h*k2)     k4=f(t+h,x+h*k3)     x=x+a*h*(k1+2*(k2+k3)+k4)     t=t+h  print t, x

example using equation dx/dt=x, x(0)=1, xf=1, h=0.1:

enter number of equations n:1 enter initial value of x0:1 enter initial value of t:0 enter final value of t:1 enter time interval h:0.1 enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] enter equation f0:x[0] 1.0 [ 2.71827974]

what should enter once differential equation program calculate all?

correct me if don't have understood. trying expression manually-typed user , treat function? found this topic explains how parse formula using sympy. can try modify program using sympy. in manner should able equation once all.

edit: if problem "how entire formula once input..." can try use raw_input() method. have here:


Comments

Post a Comment

Popular posts from this blog

qt - Using float or double for own QML classes -

-
i've created components , helper methods using c++ , qt used in qml gui. of methods calculate gui elements (size, transformations, scene graph items creation). target arm 32 bit using opengl / eglfs render output. opengl using float , qml using real (defined double ). what should use in c++ do not lose precision? if use qreal ( double ) shouldn't lose precision. if git grep float in qtbase.git , can find out bit more: dist/changes-5.2.0-**************************************************************************** dist/changes-5.2.0-* important behavior changes * dist/changes-5.2.0-**************************************************************************** dist/changes-5.2.0- dist/changes-5.2.0- - qt compiled qreal typedef'ed double on dist/changes-5.2.0: platforms. qreal float on arm chipsets before. guarantees more dist/changes-5.2.0- consistent behavior between platforms qt supports, binary dist/chan...
Read more

Create Outlook appointment via C# .Net -

-
i need create outlook appointment using microsoft.office.interop.outlook , while can work locally on own workstation , works if run web application via server's browser, not work when connect server externally. hence, think might permission issue. i changed application pool identity " localsystem " don't access denied error. unfortunately, doesn't work. the app behaves if appointment created, appointment doesn't appear in outlook. here include file on top of aspx.cs page using outlook = microsoft.office.interop.outlook; here code using pop appointment. outlook.application apptapp = new outlook.application(); outlook.appointmentitem appt = apptapp.createitem(outlook.olitemtype.olappointmentitem) outlook.appointmentitem; appt.subject = txtfirstname.text + " " + txtlastname.text; appt.body = txtcomment.text; appt.alldayevent = false; appt.start = datetime.parse(txtreminderdate.text + " 8:00 am"); appt.end = datetime.p...
Read more

ios - Swift Array Resetting Itself -

-
i have 2 arrays: pointhistory , datehistory . have nstimer , , when timer runs out, action called. in action appending int pointhistory , , current date string datehistory . here timer action: func timeraction() { let steppervalue = int(stepper.value) employee.numberofpoints = steppervalue networking.saveemployee(employee, completion: { (error) -> void in if error != nil { let alert = uialertcontroller(title: "error", message: "there error updating \(self.employee.name)'s points", preferredstyle: .alert) let alertaction = uialertaction(title: "ok", style: .cancel, handler: nil) alert.addaction(alertaction) self.presentviewcontroller(alert, animated: true, completion: nil) } }) var dateformatter = nsdateformatter() dateformatter.dateformat = "mm-dd-yyyy" dateformatter.timezone = nstimezone.localtimezone() var date = nsdate() var ...
Read more