It's like this:
/long-number/ is a single word. If the length is <19 digits, it is an
integer, otherwise a float (which necessarily has only 16 digits of
precision).
/long-number/x is a single word, but it is always an extended integer,
and every digit of /long-number/ is preserved.
x: /number/ is two words. /number/ is evaluated first, and then x: is
applied to its value to give an extended integer.
In that last case, if /number/ has more than 19 digits, it will have
been represented as a float, and the extended integer will have only 16
digits of precision.
Henry Rich
On 8/12/2023 3:25 PM, Ak O wrote:
My thought was that 'x' must always be extended by definition.
I was trying to think what cases this operator's 'x' argument would not be
strictly extended.
Chris demonstrated that the input 'x' in my example is float by
construction.
Raul explained that the parser treats the number before it treats the
operator ( if I have understood his message correctly).
So if I have understood all of this correctly. As a raw input, it is the
extended representation of the float input 'x' that is actually what is
being operated on by A. to yield the result.
Ak
On Sat., Aug. 12, 2023, 11:34 Henry Rich, <henryhr...@gmail.com> wrote:
I misunderstood your question.
(x A. y) starts by verifying that (*./ (|x) < !.#y) and then converts x
to a permutation with
(i.@-&.<: y) #: x
(all in extended precision if x is extended), followed by a number of
rotations within an index vector. It is much less work to start with
the permutation vector rather than the anagram index.
Henry Rich
On 8/11/2023 8:29 PM, Ak O wrote:
For me,
(x: y)
does not preserve the input.
The result I get is not the same.
( x:180548043269214561950911457875657 )
180548043269214573494164592263168
This does not work.
180548043269214561950911457875657x
180548043269214561950911457875657
This does work.
On Fri., Aug. 11, 2023, 13:01 Henry Rich, <henryhr...@gmail.com> wrote:
(x: value) produces extended version of value.
Henry Rich
On Fri, Aug 11, 2023, 2:44 PM Ak O <akin...@gmail.com> wrote:
Hi everybody, I hope you are all well.
I have a question about the Anagram ( A. ) operator.
In a defined function, how do I designate that an input 'x' is
treatment
as extended datatype rather than float?
Where being defined:
13 : ' x A. i.y'
[ A. [: i. ]
is to be taken as,
13 : 'X_INPUTx A. y' NB. 12345672345467x A. i.y
How do I get the affect of catenating an 'x' to the end of a number in
a
defined function?
If you understand my question ignore below, otherwise I give an
example.
Thank you for your thoughts.
Ak
My understanding of the Anagram operator (A.).
The vocabulary reference page (acapdot) gives the product of the
Anagram
index function
A. y
as datatype extended.
The Anagram function
x A. y
applies the permutation map (x) on ordered vector sequence (y) as
below.
] vector_sequence =: ?~30
20 12 4 29 7 17 22 11 2 27 28 23 6 21 9 3 24 10 26 13 15 1 18 8 25 19
0 5
16 14
] vector_anagram =: A. vector_sequence
180548043269214561950911457875657
The Noun, vector_anagram will have datatype extended, given by:
datatype vector_anagram
extended
Applying the vector_anagram on a vector using the command:
vector_anagram A. i.30
20 12 4 29 7 17 22 11 2 27 28 23 6 21 9 3 24 10 26 13 15 1 18 8 25 19
0 5
16 14
The expected result.
In a case where the digits are input on there own, the following fails
with
'domain error, executing dyad A.'
180548043269214561950911457875657 A. i.30
One approach is to place 'x:' before the input.
( x:180548043269214561950911457875657 )A. i.30
20 12 4 29 7 17 22 11 2 27 28 25 1 8 0 15 16 14 3 5 19 26 18 6 21 23 13
24
9 10
This is not the expected result.
The input is treated as 180548043269214573494164592263168.
( x:180548043269214561950911457875657 )
180548043269214573494164592263168
Not the input I thought I was applying.
An alternative is to postfix an 'x' to the end of the input.
180548043269214561950911457875657x A. i.30
20 12 4 29 7 17 22 11 2 27 28 23 6 21 9 3 24 10 26 13 15 1 18 8 25 19
0 5
16 14
The expected result. But how do I achieve this for a defined function.
Does not work either.
".@((":vector_anagram),x')"_ NB. same as x:
Maybe there is a symbol that 13 : can be recognize to trigger the
extended
datatype.
Thank you for your help.
Ak
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
