How to efficiently store the result of a function

Asked Nov 29 '20 at 14:33

Active Nov 29 '20 at 14:33

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Consider the following code:

f[x_]:= SomeCodeAbout[x]
g[x_]:= f[x]

It links g with f, namely when g is called, f runs, and so will SomeCodeAbout[x]. However, if I want just to store the result of f[x], which could be some simple expression after running the SomeCodeAbout[x], into g[x], what should I do (without manually copying the result and defining g)? The reason is simple, since SomeCodeAbout[x] could take a long time to run which is inefficient especially when g is used frequently.

asked Nov 29 '20 at 14:33

Lelouch

2

You can use f[x_] = … to evaluate the right side when defining the function instead of delaying it – Lukas Lang Nov 29 '20 at 15:07
2

To store the values of f use f[x_] := f[x] = SomeCodeAbout[x]; – Bob Hanlon Nov 29 '20 at 18:11
4

I think memoization would be the more general approach, as Bob Hanlon mentioned. See the discussion here: What does the construct f[x_] := f[x] = ... mean? – MarcoB Nov 29 '20 at 18:18

How to efficiently store the result of a function

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