## SG19 | |

**Subject:** Re: SG19 Oct 10 Zoom call

**From:** Michael Wong (*fraggamuffin_at_[hidden]*)

**Date:** 2019-10-10 14:04:29

**Next message:**Michael Wong: "Belfast SG19 scheduel up"**Previous message:**Michael Wong: "SG19 Oct 10 Zoom call"**In reply to:**Michael Wong: "SG19 Oct 10 Zoom call"

On Thu, Oct 10, 2019 at 12:13 PM Michael Wong <fraggamuffin_at_[hidden]>

wrote:

> SG19 Machine Learning 2 hours

> Topic: ISOCPP SG19 Machine Learning

> Time: May 9, 2019 1:00 PM Eastern Time (US and Canada)

> Every month on the Second Thu, until Sep 12, 2019, 5 occurrence(s)

> May 9, 2019 1:00 PM

> Jun 13, 2019 1:00 PM

> Jul 11, 2019 1:00 PM

> Aug 8, 2019 1:00 PM

> Sep 12, 2019 1:00 PM

>

> Oct 10, 2019 1 Pm

>

> Please download and import the following iCalendar (.ics) files to

> your

> calendar system.

> Monthly:

>

> https://iso.zoom.us/meeting/405838761/ics?icsToken=fe375cbeab0268c23180f074fc6795e459a2bcd0fd6bdf9a8e146fa2acd22ef0

>

> Join from PC, Mac, Linux, iOS or Android: https://iso.zoom.us/j/405838761

>

> Or iPhone one-tap :

> US: +14086380968,,405838761# or +16468769923,,405838761#

> Or Telephone:

> Dial(for higher quality, dial a number based on your current

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>

> Or Skype for Business (Lync):

> https://iso.zoom.us/skype/405838761

> <https://iso.zoom.us/skype/405838761>

>

> Agenda:

>

> 1. Opening and introductions

>

> 1.1 Roll call of participants

>

Millan Girkar (Intel), Phil Ratsloff( SAS), Marco Foco (nvidia0, Andrew

Lumsdaine (U W), Richard Dosselwamn (U R), Michael Wong (CP), Jens Maurer,

Domagoj Saric

1.2 Adopt agenda

>

> 1.3 Approve minutes from previous meeting, and approve publishing

> previously approved minutes to ISOCPP.org

>

> 1.4 Action items from previous meetings

>

> 2. Main issues (125 min)

>

> 2.1 General logistics

> All C++ reflector are now moved to listserv

>

> https://lists.isocpp.org/mailman/listinfo.cgi/sg19

>

> 2.2 Paper reviews

>

> Review Belfast paper submission strategy

>

https://isocpp.org/papers

to submit papers

need an isocpp password

> 2.2.1: ML topics

> Differentiable Programing by Marco Foco

>

new person implemented in clang

He will be at Belfast

Vassil Vassilev

> Richard Dosselman

>

> P1708R1: Math proposal for Machine Learning

>

> https://docs.google.com/document/d/1VAgcyvL1riMdGz7tQIT9eTtSSfV3CoCEMWKk8GvVuFY/edit

>

instead of independent functions that ake one pass over the data, that was

based on python

we have a range where we can walk once so computation are free and do

multiple scan

load a variety of entity over that range

and individually load the value to be evaluated

Mean: has an overload and not just set

just like evrything else in general standards algorithm template, follows

the accumulator function as well

e.g:

integer list of fixed pre-determiend size

then accumulator which operates over that set

this is like boost accumulator library, given a set then load a function,

from eric niebler

versatile as to which set it applies to

first one does just one statistics

e.g. 2

structure, o have to have notion of what mean is

now accumumulating over a set of point, but result is a single scalar

lambda describe what we mean to be computing the average

can use this to create midpoint, geometric and harmonic mean is for the

future

3.3

median requires sorting you wont know the middle until sorted

quick select is a popular same designer as quick sort

return value: iterator to the individual mean median, now aming for

structure where we return a first or second median

can ask for both mean and median

should we allow people to know there are 2 medians

why get<1> instead <0>, off by 1 error

when I apply median will get 2 values, magenta and cyan

python for median of even number integers, probably averages them resulting

in floats as they dont have support for integers

no support for strings? averaging signals, images

dont design it to force string to work, it is outside of problem domains,

but if it works great

for mean yo usum individual pixels and divide by number of elements

if you have an image unit8, when u accumulate it in a wider type, after

dividing it goes back to unit8

so intermediate type is also different

std::accumulate already support different types for accumulator, this is

good

Mode: needs a hash table

where is the vector and why optional? possibility if there is no return

value at all

are there several results?

worry we are returning a vector as it allocates memory which means passing

in an allocator, a range would be better

but this would deviate from standard unlike median mean

we seem to have this problem anyway

Not sure how a range would be use in this case, it would have to be sorted

order

Standard deviation

simpler cases

dont do example 2 in 3.5, look at ranges for projections that have

algorithm built in

3.6 Variance

asked for by Jens,

Median /mode seems to need different treatment , needs memory allocation,

and hash tables

>

> P1709R1: Graph Proposal for Machine Learning

>

>

> https://docs.google.com/document/d/1QkfDzGyfNQKs86y053M0YHOLP6frzhTJqzg1Ug_vkkE/edit?usp=sharing

> <https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.google.com%2Fdocument%2Fd%2F1QkfDzGyfNQKs86y053M0YHOLP6frzhTJqzg1Ug_vkkE%2Fedit%3Fusp%3Dsharing&data=02%7C01%7CPhil.Ratzloff%40sas.com%7C729b2cf8502641e4ae5e08d749064578%7Cb1c14d5c362545b3a4309552373a0c2f%7C0%7C0%7C637058163592253027&sdata=4UQm8tqrcUbiZsr200UMrOaEModJYGNgP1oNot9PbAg%3D&reserved=0>

>

>

>

was trying to support OO interface, now switching to a functional interface

like erasing an edge on a vertex, so need the context of a graph

store a graph pointer, so now start lookign at concepts, what are those

functions instead of having a table

COncepts: there are just definitions, no implemenation yet, trying to

present the concepts that will be useful throughout definiiton we will be

using

using _c to designate a concept type

have to get vertexes and edges of the graph

there is an arithmetic concept, based on the arithmetic type

for depth-search first

intoduced type_traits for is this an adjancey array, list , etc

there is graph value type

vertex key, vertex value,

ways of creating vertex, can pass vertex by rvalue reference, can erase

vertexes or in a range, clear, find

can erase edges, or based on in out edge iterator

can find an edge based on vertex iterators or keys

can do same for in out edge

why does adjancey list return a Grpah type? Yes, it was suppose to be a

pointer to an object (that is newly allocated object, then it needs to be a

managed pointer or object by value, and should not be return by raw

pointer; Ok if we return unique pointer the need to do more work for a

shraed pointer) , need to specify what G means, this needs some more

attention

why shoudl this helper function be at the top level? Should we not use

concept based,

all kinds of data structure that can meet the concept of the graph or

adjanceny list and that should make up a list of vectors, we had that in

BGL; seems like you want to be able build up from that to sparse matrix

depth first and breath first search are really iterators! agree

so Iterator example shows how to create a graph G1 with adjacency list

DFS range first item is vertex where you are at, the second part s a

sentinel

yes this makes perfect sense to me, definitely approach we have been using

for BGL 17

same example in breath first search with different ordering coming out

graph_c G is reused everywehere, should they not be differerent concepts,

as BFS and DFS is just reading, if you are reusing this for erase function

,

yes so far these are generic

TopoSort

Algorithm

shortest path

BFSP

dijkstra reuires nonnegatve weighs, consier a concept for that which would

require unsigned integers

there are no unsigned doubles, and doubles is a possible weights

connected component is an undirected graph

Dont do tuples, as they dont have names as they use get<0>, which we dont

know what they are

get named members like ranges

Do you have a description of graph_c concept? Yes in Concepts, directed

and undirected

need to have good definitions

an unidrected graph should not be required to have an erase function. Is

that from easable? May be just check

I Have a concept Erasable

could be mixing 2 things, algo which operate on a graph, and these Graph

functions that appear to operate on predefined graph data structure that

you offer in your library and they look the same but take your specific

Graph type, they should take a generic graph type.

Agree, but they could be overwritten wit user-defined functions and these

perform the desire goal.

But now you require each of these functions and that expands the interface

greatly

I see if I want to adapt my thing, then I want to know what I want to

override, this is the point of Concept

Right, I cant tell what the minimum set of operations that is needed

industry is moving away from library solutions like TVM, Glow these are

compile time generated graphs

yes in scope just not today,

vertexes and edges are compield time constnat and these would be optimized

vertex iterator concept, some produce pairs of vertex iterator, no implied

navigation on these vertexes

what does increment do on these? Nothing for shortest path. Perhaps minimum

requirement to satisfy

so no need for ++ unless I really need it but for some algo, being an

iterator vs being a pointer or reference really means, you dont really need

a random access iterator into the next function?

example for transitive closure for modifying tht grah nd how to produce a

fresh graph tht is a transitive closure of another graph to demonstrate the

interface as given works

why create_adjancency list just creates a graph. So why need a special

creation function for graph? Because I was trying to create a functional

definition.

adjacency list that is initiliazed with an initialized list? Yes useful

also having global functions that modify graphs.

P1416R1: SG19 - Linear Algebra for Data Science and Machine Learning

>

> https://docs.google.com/document/d/1IKUNiUhBgRURW-UkspK7fAAyIhfXuMxjk7xKikK4Yp8/edit#heading=h.tj9hitg7dbtr

>

> P1415: Machine Learning Layered list

>

> https://docs.google.com/document/d/1elNFdIXWoetbxjO1OKol_Wj8fyi4Z4hogfj5tLVSj64/edit#heading=h.tj9hitg7dbtr

>

> 2.2.2 SG14 Linear Algebra progress:

> Different layers of proposal

>

> https://docs.google.com/document/d/1poXfr7mUPovJC9ZQ5SDVM_1Nb6oYAXlK_d0ljdUAtSQ/edit

>

> 2.2.3 any other proposal for reviews?

>

> 2.3 Other Papers and proposals

>

> 2.5 Future F2F meetings:

>

> 2.6 future C++ Standard meetings:

> https://isocpp.org/std/meetings-and-participation/upcoming-meetings

>

> - *2019-11-04 to 09: Belfast, Northern Ireland;* Archer Yates

>

> -2020-02-10 to 15: Prague, Czech Republic

>

> - 2020-06-01 to 06: Bulgaria

> - 2020-11: (New York, tentative)

> - 2021-02-22 to 27: Kona, HI, USA

>

> 3. Any other business

>

> New reflector

>

> http://lists.isocpp.org/mailman/listinfo.cgi/sg19

>

> Old Reflector

> https://groups.google.com/a/isocpp.org/forum/#!newtopic/sg19

> <https://groups.google.com/a/isocpp.org/forum/?fromgroups=#!forum/sg14>

>

> Code and proposal Staging area

>

> 4. Review

>

> 4.1 Review and approve resolutions and issues [e.g., changes to SG's

> working draft]

>

> 4.2 Review action items (5 min)

>

> 5. Closing process

>

> 5.1 Establish next agenda

>

> TBD

>

> 5.2 Future meeting

>

> Aug 8

> Sep 12

> Oct 10: Mailing deadline Oct 7

> Nov 14 - cancelled due to DST change and switching to a new cycle.

>

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