memofunc v1.0.2
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Function Memoization
A simple way to memoize function results to improve performance by eliminating unnecessary computation or data retrieval activities.
Readme
MemoFunc - A Function Memoization Package for R
A simple way to memoise function results to improve performance by eliminating unnecessary computation or data retrieval activities.
Functions can be memoized with a simple call to memo.
> # a simple example function
> simple.function <- function (value) {
+ print("Executing!")
+ value
+ }
> # call memo function to memoise a function
> simple.function.memo <- memo(simple.function)
> # or like this
> simple.function %<>% memo()
> # or like this
> simple.function2 <- (function (value) value) %>% memo()
Calling a memo is exactly like calling a normal function, in fact it is a normal function! The memo has all the same arguments and defaults as the origional function so it can be used in legacy code without the need for any risky refactoring.
> # the first time we call the memo the function will execute
> simple.function(10)
[1] "Executing!"
[1] 10
> # if we call the function again with the same parameter values then
> # the cached value will be returned
> simple.function(10)
[1] 10
> # calling the memo with a different set of parameter values will
> # cause the function to execute
> simple.function(20)
[1] "Executing!"
[1] 20
Memoing a function can significantly improve the performance of a system by limiting how often expensive call are made. Functions that return a NULL value can be memoed by using the allow.null argument.
> # consider a slow function which is memoised, note that we have used the allow.null argument
> # so that NULL is cached when returned from a function, the default is FALSE
> slow.function <- (function (value) Sys.sleep(value)) %>% memo(allow.null = TRUE)
> # the first time we call the slow function it takes some time
> system.time(slow.function(3))
user system elapsed
0.00 0.00 3.01
> # subsequent calls make use of the cache and are much faster
> system.time(slow.function(3))
user system elapsed
0.01 0.00 0.02
Installation
devtools::install_github("rwetherall/memofunc")
Functions in memofunc
Name | Description | |
storage.has.default | Has key has been used to store a value in a memory store? | |
storage.get | Get value from a store. | |
storage.clear.default | Clear the memory store. | |
memofunc | memofunc: A package for memoizing functions and caching data | |
storage.clear | Clear the storage. | |
storage.init | Initialize a store. | |
storage.unset | Unset a value that corresponds to a key within a store. | |
storage.set.default | Set value into a memory store. | |
storage.has | Has key has been used to store a value? | |
storage.get.default | Get a value from a memory store. | |
storage.unset.default | Unset a value that corresponds to a key within a memory store. | |
storage.init.default | Initialize a memory store. | |
hash.function | Hash | |
storage.set | Set value into a store. | |
hash.list | Hash | |
hash.functionCall | Hash | |
hash.default | Hash | |
functionCall | Function Call | |
hash | Hash | |
memo.cache | Memo Cache | |
memo.function | Memo Function | |
is.memo | Is Memo | |
memo | Memo | |
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Details
Type | Package |
License | GPL-3 |
URL | https://github.com/rwetherall/memofunc, https://rwetherall.github.io/memofunc/ |
BugReports | https://github.com/rwetherall/memofunc/issues |
Encoding | UTF-8 |
LazyData | true |
RoxygenNote | 7.1.1 |
NeedsCompilation | no |
Packaged | 2021-02-20 23:06:35 UTC; rweth |
Repository | CRAN |
Date/Publication | 2021-02-22 19:30:02 UTC |
suggests | covr , devtools , roxygen2 , testthat |
imports | digest , magrittr , uuid |
depends | R (>= 3.5.0) |
Contributors | Roy Wetherall |
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