Re: Deleting more subtle then Clear[ ] ?

*Subject*: [mg2273] Re: [mg2234] Deleting more subtle then Clear[ ] ?*From*: hay at haystack.demon.co.uk (Allan Hayes)*Date*: Thu, 19 Oct 1995 05:35:04 GMT*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: Wolfram Research, Inc.*Sender*: daemon at wri.com ( )

alfred at ca-risc.co.at in [mg2234] Deleting more subtle then Clear[ ] ? asks about selective clearing (see attached messege). I hope the following example may help. f[x_,y_] := f[x,y] = x -y Do[f[x,y], {x,1,2},{y,1,2}] ?f Global`f f[1, 1] = 0 f[1, 2] = -1 f[2, 1] = 1 f[2, 2] = 0 f[x_, y_] := f[x, y] = x - y dv = DownValues[f] {Literal[f[1, 1]] :> 0, Literal[f[1, 2]] :> -1, Literal[f[2, 1]] :> 1, Literal[f[2, 2]] :> 0, Literal[f[x_, y_]] :> (f[x, y] = x - y) } Now change DownValues by standard techniques. For example DownValues[f] = Cases[dv,e_/;FreeQ[e, Literal[f[_?NumberQ,_?NumberQ]]]] {Literal[f[x_, y_]] :> (f[x, y] = x - y)} ?f Global`f f[x_, y_] := f[x, y] = x - y Allan Hayes hay at haystack.demon.co.uk ********* Begin forwarded message: >From: alfred at ca-risc.co.at >To: mathgroup at smc.vnet.net >Subject: [mg2234] Deleting more subtle then Clear[ ] ? >Organization: EUnet EDV DienstleistungsgesmbH, Wien Well, Let's assume we have a function f[x,y,z] where x and y are VERY big or time consuming lists of numbers or functions. By defining f[x_,y_,z_]:= f[x,y,z] = I make MMA remember what it did. How can I now tell it to disremember for all f[x,*,*] when I specifically want it to reprocess whatever is dependend on x (i.e. the contents of the file has changed but the name is the same) but NOT on y? Thanks for help Alfred -- ================================ Alfred H. Corrodi "Capitalism is based on the assumption Risk Manager that you can win the game. Communism Creditanstalt-Bankverein is based on the assumption that you can alfred at ca-risc.co.at (NeXT) break even. Mysticism is based on the Tel/43/1/531311967 Fax/5337341 assumption that you can leave the game."