# Interpretation of output derivative expression [duplicate]

I am trying to write Mathematica file to find Div, Grad, Laplacian, etc. in coordinates given by a metric tensor w.r.t Euclidean coordinates.

In test my file, I am first trying it on cylindrical coordinates $(r,\theta,z)$. Here $f$ is defined as a scalar valued function dependent on these coordinates.

I am running into the following problem. In one of the steps, I get terms like the following:

$2f^{(0,1,0)}\lbrack r,\theta,z\rbrack^{(0,1,0)}\lbrack r,\theta,z\rbrack$

$2f^{(0,1,0)}\lbrack r,\theta,z\rbrack\lbrack r,\theta,z\rbrack$

How do I interpret these? Are they different or do they mean the same thing? I know that the superscripts refer to derivative with respect to the coordinate that is non-zero.

• The output is very likely not what you want, and indicates that you did something wrong. Since you didn't say what input you actually used, I can only guess that you will find the answer to your problem here: How to write a differential operator in Mathematica. Another possible source of inspiration is: Having the derivative be an operator
– Jens
Jun 12, 2013 at 21:47
• Another possible source to look at: How to change coordinates of a differential operator?
– Jens
Jun 12, 2013 at 21:50
• You may also take a look at this: Using D to find a symbolic derivative Jun 12, 2013 at 23:04
• Perhaps you are missing some semicolons in your input, and various terms are getting (erroneously) multiplied by each other. Jun 13, 2013 at 3:04
• There are several votes to close as a duplicate, but I do not find that the question asked here is answered in the duplicates. I would say it is probably too localized, since it appears from what has been given that it is probably a coding error. Jun 13, 2013 at 14:22