"Fixed for the next beta" suggests you might have overlooked that this problem seems to occur in J9.02 as well.
Apologies if I'm wrong.

Cheers,

Mike

On 15/02/2021 17:16, Henry Rich wrote:
It comes down to this:

    <. 17575011601890. 0  NB. bug!
17575011601891 0
    <. 17575011601890.
17575011601890

When I rewrote >. to allow inplace operation, I forgot that comparison tolerance causes trouble when the numbers get big. Singletons follow a different path.

Fixed for next beta.  Thanks for the report.

NOTE that tolerant <. gives non-intuitive results on large float values:

   <. 20000000000000.6
20000000000001

You got a problem with that?  You asked for 'the largest integer tolerantly less than or equal to y', didn't you?

Henry Rich

On 2/15/2021 4:59 AM, Stefan Baumann wrote:
Dear all,
I had an issue when calculating the triangular number with the formula
<.@:-:@:(*
:) in list context. Starting from 5928745 the outcome in list context is
larger than the correct value (additionally calculated with the binomial
coefficient in the first box):

    t=: <.@:-:@:(* >:)
    ((2&!)@:>:; t ;{.@:t@:,~) 5928744
+--------------+--------------+--------------+
|17575005673140|17575005673140|17575005673140|
+--------------+--------------+--------------+
    ((2&!)@:>:; t ;{.@:t@:,~) 5928745
+--------------+--------------+--------------+
|17575011601885|17575011601885|17575011601886|
+--------------+--------------+--------------+
    JVERSION
Engine: j902/j64avx2/windows
Release-a: commercial/2020-12-05T13:36:01
Library: 9.02.08
Platform: Win 64
Installer: J902 install
InstallPath: c:/users/wzhbsn/_/opt/j
Contact: www.jsoftware.com

Thanks. Stefan.
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