for the sentence
a =: ('b' ,~ 3 ,~ ]) a
only 9!:53[0 can prevent half-modified, so that
9!:53[1 is still unsafe?
Correct.
On the other hand the sentence
a =: ('b' ,~ 3 ,~ ]) a=: 3 1 4 1 5 9 2
This is not inplaceable because the block has a usecount of 2 after the
assignment
Can you also elaborate the difference between 9!:53[1 and 2?
9!:53 (2) allows an operation to be executed in-place even if it might
be aborted because of error.
An example would be
a =: 0 1 2 3 4 _ 6 7
a =: 2 | a
which will fail with a NaN error. If 9!:53 (2) is set, a will be
partially modified. Settings of 0 or 1 will not perform the operation
in-place.
[Note: I have not finished in-placing arithmetic verbs. None of the
verbs in the beta fail after partially modifying an argument.]
Henry
On 10/6/2016 11:29 AM, bill lam wrote:
Henry, I still don't understand, consider the
following log on the current beta-12.
<<<<<<<<<<<<<<< log started
9!:53[0
a=: 3 1 4 1 5 9 2
a =: ('b' ,~ 3 ,~ ]) a
|domain error
| a=: ('b',~3,~])a
a
3 1 4 1 5 9 2
9!:53[1
a =: ('b' ,~ 3 ,~ ]) a
|domain error
| a=: ('b',~3,~])a
a
3 1 4 1 5 9 2 3
a=: 3 1 4 1 5 9 2
9!:53[2
a =: ('b' ,~ 3 ,~ ]) a
|domain error
| a=: ('b',~3,~])a
a
3 1 4 1 5 9 2 3
9!:53[0
a =: ('b' ,~ 3 ,~ ]) a=: 3 1 4 1 5 9 2
|domain error
| a=: ('b',~3,~])a=:3 1 4 1 5 9 2
a
3 1 4 1 5 9 2
9!:53[1
a =: ('b' ,~ 3 ,~ ]) a=: 3 1 4 1 5 9 2
|domain error
| a=: ('b',~3,~])a=:3 1 4 1 5 9 2
a
3 1 4 1 5 9 2
9!:53[2
a =: ('b' ,~ 3 ,~ ]) a=: 3 1 4 1 5 9 2
|domain error
| a=: ('b',~3,~])a=:3 1 4 1 5 9 2
a
3 1 4 1 5 9 2
<<<<<<<<<<<<<<< log ended
for the sentence
a =: ('b' ,~ 3 ,~ ]) a
only 9!:53[0 can prevent half-modified, so that
9!:53[1 is still unsafe?
On the other hand the sentence
a =: ('b' ,~ 3 ,~ ]) a=: 3 1 4 1 5 9 2
There is no half-modified, for all 9!:53[0 1 2
because this sentence is not eligible for in-place
operation? or some other reasons?
Can you also elaborate the difference between 9!:53[1 and 2?
Ср, 05 окт 2016, Henry Rich написал(а):
9!:53 (0) will run in-place only on the last (or only) verb in a compound,
and only if that verb will complete without error.
9!:53 (1) will run in-place wherever the previous contents of the
to-be-assigned noun are no longer needed, and only if that verb will
complete without error.
9!:53 (2) will run in-place wherever the previous contents of the
to-be-assigned noun are no longer needed.
Henry Rich
On 10/5/2016 12:28 PM, Don Guinn wrote:
Thread moved to beta.
Determining when in line processing is okay can get very difficult,
depending on how extensive one wants to be. J already does checking on
compatibility of arguments before it begins actual execution on data. When
the assigned name is an argument in the execution in line processing can
give a significant performance boost. When only one primitive is involved
determining if in line processing is okay should not be too difficult. But
when multiple primitives are in the expression it can get difficult. All
the cases presented as failures have involved multiple primitives in the
expression. Perhaps limiting in line processing to single primitive
expressions at first, especially for primitives not rank 0, then extend
later.
9!:53 can take 0, 1 and 2 . Do 1 and 2 give different levels of
aggressiveness of in line checking? If not then maybe 1 could provide
"safe" in line processing and 2 could extend in line to the questionable
cases.
On Tue, Oct 4, 2016 at 6:34 PM, Xiao-Yong Jin <[email protected]> wrote:
On Oct 4, 2016, at 2:01 PM, Louis de Forcrand <[email protected]> wrote:
Maybe add a third setting to 9!:53 which copies a at the start of a
tacit verb involving in place operations?
This is a good compromise between speed and sensible intuition.
I guess a memcpy only when in-place-operation is detected wouldn't be
slower in general than previous non-in-place operations.
This could certainly be the default option.
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