Re: [Bug-apl] performance in of ¨

[Christian Robert]

On 2016-06-19 23:55, Xiao-Yong Jin wrote:
> Jürgen, I can confirm that loop problem is fixed.

> Christian, that “function” is an operator, same as each (¨). You would find it 
> listed in )ops, similar to ⎕NL 4, and ⎕NC'FE' would return 4 (as an operator).  
> In gnu apl you can use )nms to list all the )vars )fns and )ops.

thank you Xiao-Yong,

I was not aware of the distinction between functions and operators. Learning 
every day.

Xtian.
> Best,
> Xiao-Yong
>
> > On Jun 19, 2016, at 12:16 AM, Christian Robert <address@hidden> wrote:
> >
> > I think you fixed it. No longer running O(NxN) (still slower than native C++, I 
> > can live with that, no problems)
> >
> > btw, When I defined this test function two days ago:
> >
> >
> >      f2def 'FE'
> >
> >      )sic
> >      )erase FE
> >
> >      ∇Z←A (LO FE) B;rho_Z;N;N_max
> > rho_Z←⍴B ◊ N←⎕IO ◊ A←,A ◊ N_max←N+⍴B←,B ◊ Z←N_max⍴0
> > LOOP: Z[N]←⊂(⊃A[N]) LO ⊃B[N] ◊ →(N_max>N←N+1)⍴LOOP
> > Z←rho_Z⍴Z
> > ∇
> >      )fns
> > D   MEASURE     MEASURE2    Replace     df  f2def   ltrim   rtrim   time    
> > trim    vert
> >      ⍝ FE does not appear here ! But *is* a function
> >
> >      ⍝ but this function name appear in ⎕nl 4
> >
> >      D ⎕nl ¨ ⍳4
> > ┌4──────────────────────┐
> > │┌⊖┐ ┌⊖┐ ┌8───────┐ ┌2─┐│
> > │⌽ │ ⌽ │ 1D       │ ↓FE││
> > │└─┘ └─┘ 1MEASURE │ └──┘│
> > │        │MEASURE2│     │
> > │        │Replace │     │
> > │        │df      │     │
> > │        │f2def   │     │
> > │        │ltrim   │     │
> > │        │rtrim   │     │
> > │        │time    │     │
> > │        │trim    │     │
> > │        │vert    │     │
> > │        └────────┘     │
> > └∊──────────────────────┘
> >
> > what is {quad}nl 4 ?
> >
> > why 'FE' not displayed in ")fns" ?
> >
> > Xtian.
> >
> >
> > On 2016-06-18 16:21, Juergen Sauermann wrote:
> > > Hi,
> > >
> > > I believe I have fixed the problem,*SVN **749*.
> > >
> > > The fault was actually not related to macros but a general problem
> > > affecting the performance of virtually all workspaces.
> > >
> > > The time-consuming line in the EACH macro was this:
> > >
> > > *LOOP: Z[N]←⊂(⊃A[N]) LO ⊃B[N] ◊ →(N_max>N←N+1)⍴LOOP*
> > >
> > > Due to an inefficiency in the runtime parser, the parser would, for example, 
> > > first resolve
> > > B (which creates a copy of B) and then index the copy to obtain B[N] . Same for 
> > > A.
> > > If B has N items then this would generate N copies of B, each copy taking O(N) 
> > > cycles,
> > > and therefore the runtime of the above innocent looking LOOP would be O(N×N).
> > >
> > > Macros are a little slower than their built-in siblings, but the code that 
> > > could be removed
> > > by using macros belonged to the most error-prone in the past, and some of the 
> > > built-in
> > > operators (which are called when their function argument(s) are primitive 
> > > functions) could
> > > also be simplified.
> > >
> > > /// Jürgen