differentiate multivariable InterpolatingFunction?

*Subject*: [mg2243] differentiate multivariable InterpolatingFunction?*From*: bhunt at brians.umd.edu (Brian R. Hunt)*Date*: Wed, 18 Oct 1995 05:54:49 GMT*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: Project GLUE, University of Maryland, College Park, MD*Sender*: daemon at wri.com ( )

I am using Mathematica 2.2. It is possible to differentiate an InterpolatingFunction of 1 variable, e.g. if u is an InterpolatingFunction defined from 0 to 10, then I can ask for u'[3] or define v[x_] = D[u[x],x] or whatever. If u is an InterpolatingFunction of 2 variables, is it possible, using D or Derivative or something built-in, to get a numerical value for the partial derivative of u with respect to it first argument at a specific point? I have tried several plausible forms of syntax (and no doubt several implausible ones as well), but no luck. Thanks in advance for any suggestions; an authoritative "it can't be done" would also be helpful so I can stop trying. -- Brian R. Hunt bhunt at ipst.umd.edu