Re: Parculiarities of FindRoot

*To*: mathgroup at smc.vnet.net*Subject*: [mg116071] Re: Parculiarities of FindRoot*From*: DrMajorBob <btreat1 at austin.rr.com>*Date*: Tue, 1 Feb 2011 06:51:45 -0500 (EST)

Limiting "func" to numeric input prevents FindRoot trying to use a symbolic one. Clear[func] func[y_?NumericQ] := Module[{x}, x^2 /. FindRoot[x + y == 0, {x, 0.}] ] func[.2] 0.04 FindRoot[func[z], {z, 0.}] {z -> 0.} Block also works, in place of Module. Bobby On Mon, 31 Jan 2011 02:24:17 -0600, Tianhui Li <tianhuil at princeton.edu> wrote: > Here's a question for the group: in the following function, Func seems > to evaluate numerical arguments correctly and *works* when you throw > it into a FindRoot. But the second command generates a lot of warning > messages. Does anyone understand why? > > Func[y_] := x^2 /. FindRoot[x + y == 0, {x, 0.}] > Func[.2] > FindRoot[Func[z], {z, 0.}] > > Warm Regards, > Michael Li > Bendheim Center for Finance > Princeton University > Princeton, NJ 08544 > -- DrMajorBob at yahoo.com