I have not studied your msg in detail but I note that
sparse boxed arrays are not supported.



----- Original Message -----
From: Fraser Jackson <[EMAIL PROTECTED]>
Date: Friday, February 29, 2008 23:59
Subject: [Jbeta] Unexpected  verb behaviour with a sparse array argument
To: Beta forum <[email protected]>

> The following using the r beta has some behaviour I do not 
> understand. On 
> testing it appears unchanged from J601.
> 
> The first section below is a session log.  The second 
> section the script.
> 
> Log ******************
>    a =: >: ?. 2 3 4$20
> 
>    b =: $.a
> 
>    marginald =: 4 : 0
> x =. >x     NB.  provide option of 
> either boxed or unboxed x arg
> +/ ^:(n-#x) (  (vi =. (i.(n =. #$y)) -. x),x)|: y
> )
> 
>    marginal1sp =: 4 : 0
>  < 0$. x marginald y
> )
> 
> 
>    c =: 0 marginal1sp b
> 
>    3!:0 c
> 32
> 
>    ( i.#$b)  marginal1sp "0 _  b
> 1 │ ┌───────────┐
> 2 │ │114 88 77  │
>   │ ├───────────┤
>   │ │68 88 52 71│
>   │ └───────────┘
> 
>    Note 'Questions and comment'
> 1.  the result of marginal1sp is a box atom not a
> sparse boxed atom. Why is the result of the above line
> a sparse array?
> 
> 2.  there are three atoms in the left argument.  Why does
> the result only contain two results?  Is there a bug in
> the display of sparse arrays here?
> 
> 3.  I get the expected result with three elements
> when I enter
> 
> 0 $. ( i.#$b)  marginal1sp "0 _  b
> 
> )
> 
> Script **************************
> a =: >: ?. 2 3 4$20
> 
> b =: $.a
> 
> marginald =: 4 : 0
> x =. >x     NB.  provide option of 
> either boxed or unboxed x arg
> +/ ^:(n-#x) (  (vi =. (i.(n =. #$y)) -. x),x)|: y
> )
> 
> marginal1sp =: 4 : 0
>  < 0$. x marginald y
> )
> 
> 
> c =: 0 marginal1sp b
> 
> 3!:0 c
> 
> ( i.#$b)  marginal1sp "0 _  b
> 
>  0 $. ( i.#$b)  marginal1sp "0 _  b
> End of script ***********************************
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