Displaying 8 results from an estimated 8 matches for "unflattening".
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flattening
2008 Nov 13
1
Unflatten a table in R
Hi All,
I'm pretty new to R, so would really appreciate it if someone could point me
in the right direction on this problem.
I am trying to "unflatten" a table in R, and can't seem to find a function
or method to complete this task, (hopefully efficiently).
My data table is full of historical stock-market data. Daily, each
ticker-symbol has four data points: open, close,
2010 Apr 30
2
Flattening and unflattening symmetric matrices
Here's an easy question: I'd like to convert a symmetric matrix to a
vector composed of the upper.tri() part of it plus the diagonal, and
convert it back again. What's the best way to achieve this? I'm
wondering if there are some built in functions to do this easily. I
can encode fine:
v <- c(diag(A),A[upper.tri(A)])
but I don't see an easy way to recover A from v
2006 Jul 19
1
How would you export a 3-dimensional array to an SQL database?
Hello,
How would you export a 3-dimensional array to an SQL database?
a<-array(1:24, 2:4)
Is there an open source DB that would be more adequate for this type of
operation?
Is there a way to reshape/flatten a 3-dimensional array?
Regards,
Pierre Lapointe
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2019 Jul 21
6
[RFC] A new multidimensional array indexing intrinsic
Hello,
We would like to begin discussions around a new set of intrinsics, to
better express
multi-dimensional array indexing within LLVM. The motivations and a
possible design
are sketched out below.
Rendered RFC link here
<https://github.com/bollu/llvm-multidim-array-indexing-proposal/blob/master/RFC.md>
Raw markdown:
# Introducing a new multidimensional array indexing intrinsic
## The
2019 Jul 22
2
[RFC] A new multidimensional array indexing intrinsic
> It seems that the main advantage of your proposal is that it would allow for non-constant strides (i.e. variable length arrays) in dimensions other than the first one. Do these appear frequently enough in the programs that you're interested in to be worth optimizing for?
Yes - at least in Chapel (which is one of the motivating languages)
these are very common.
In other words, typical
2019 Jul 22
2
[RFC] A new multidimensional array indexing intrinsic
We could also simply extend the existing inrange mechanism to
non-constantexpr GEPs. It would remove an inconsistency in the
semantics, be relatively straight forward, and solve the motivating
example.
(I didn't read the proposal in full, so there may be other examples it
doesn't solve.)
Philip
On 7/22/19 10:01 AM, Peter Collingbourne via llvm-dev wrote:
> The restrictions of
2019 Jul 25
0
[RFC] A new multidimensional array indexing intrinsic
It's also very common in Fortran.
-David
Michael Ferguson via llvm-dev <llvm-dev at lists.llvm.org> writes:
>> It seems that the main advantage of your proposal is that it would
>> allow for non-constant strides (i.e. variable length arrays) in
>> dimensions other than the first one. Do these appear frequently
>> enough in the programs
2019 Jul 22
1
[RFC] A new multidimensional array indexing intrinsic
Intrinsics can return `llvm_any_ty` (Intrinsics.td). In that case the
return type is added as a suffix to the intrinsic's name, i.e. the
syntax in the RFC is not 100% the syntax for intrinsics. Same for the
parameters which each must have their types explicitly mentioned.
Michael
Am Mo., 22. Juli 2019 um 19:08 Uhr schrieb Kaylor, Andrew
<andrew.kaylor at intel.com>:
>
> Is it