Re: Function with optional default argument cannot cache
- To: mathgroup at smc.vnet.net
- Subject: [mg130678] Re: Function with optional default argument cannot cache
- From: Waclaw Kusnierczyk <waku at idi.ntnu.no>
- Date: Wed, 1 May 2013 21:40:10 -0400 (EDT)
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- Delivered-to: l-mathgroup@wolfram.com
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- References: <20130501073754.8ADA36A27@smc.vnet.net>
Interesting. Looks like you'd need to cover the default value case
manually:
f[x_, y_] := f[x, y] = {Pause[1], x, y}
f[x_] := f[x, 2]
But arguably it should not be necessary.
vQ
On 05/01/2013 09:37 AM, Dan O'Brien wrote:
> Is there a discussion somewhere on why this is?
>
> In[1]:= $Version
> f[x_, y_: 2] := f[x, y] = {Pause[1], x, y}
> f[1, 2] // AbsoluteTiming
> f[1, 2] // AbsoluteTiming
> f[1] // AbsoluteTiming
> f[1] // AbsoluteTiming
>
> Out[1]= "9.0 for Microsoft Windows (64-bit) (January 25, 2013)"
>
> Out[3]= {1.014002, {Null, 1, 2}}
>
> Out[4]= {0., {Null, 1, 2}}
>
> Out[5]= {1.029602, {Null, 1, 2}}
>
> Out[6]= {1.014002, {Null, 1, 2}}
>
- References:
- Function with optional default argument cannot cache results
- From: Dan O'Brien <danobrie@gmail.com>
- Function with optional default argument cannot cache results