Hello all, I want to use a user-defined function (say, Maxwell distribution function) with a variable (say, p--momentum, because I want to integrate the function on that variable), and want to use density and temperature field information of each grid. This function applies individually on each grid. Please suggest me the way to do so. This could be very naive to ask but I stuck in it. That function can't be a yt-field (I think) because it has a variable, and if I want to use density and temperature field even after removing units inside the function, it will show an error, because the field is in vector form (3Dim) and the variable is scaler (basically shape miss-match error). I have to use many such functions as post-processing, please suggest me a way to achieve this goal. Many thanks and regards, -Prateek Gupta