Lead Developer Role for GreyconMill Projects

Trim Optimisation Speed Focus in 8.0

Greycon is pleased to

announce the 8.0 release

on Valentine’s day, 14th

February.

This release delivers

significant computational

improvements in the trim

optimisation engine, which

affects X-Trim, opt-Studio

and GreyconMill (the

latter’s release number is

2.5 SR2). These

improvements are due to

the replacement of the

previous linear / integer

programming library with

an alternative state-of-the-

art library from Gurobi.

Roughly speaking, for

small problems the

computational times and

solutions are unchanged,

but for large problems:

The solutions are

(very slightly)

better, both in terms

of the objective

function and also in

terms of pattern

counts (see p. 2).

The computational

times have been

reduced by >20%.

The Gurobi library

also makes better

use of multiple cores

(see p.3).

The changes, which have

required many months’

work, are further analysed

GREYCON

February 2014

GreyLetter

Inside this issue:

X-Trim 8.0

Improvements

2

Trim Optimisation

Computational Aspects

3

opt-Studio Trim Solution

Display Improvements

4

opt-Studio Stock

Compatibility Formula

4

Variable Diameter Trim

Optimisation

5

X-Trim Film Charting 5

GreyconMill Core Cutter

& Other Interfaces

6

GreyconMill Mobile

Clients

6

GreyconMill Warehouse 6

Effort in 8.o 7

Copy Control Aspects 7

in multiple separate

articles in this newsletter.

In addition to these

changes, working in

conjunction with DuPont,

we have extended the

manual editing capabilities

in X-Trim to allow for

some pretty amazing

solutions (see p. 5).

opt-Studio also contains a

bunch of improvements,

both in terms of usability

and also in terms of

flexibility. Regarding the

latter, the compatibility

checks for stock allocation

are now user-defined via

the familiar and powerful

formula mechanism.

Greycon Suite

8.0 was

released 14th

February

GreyconMill is now

beginning to get a non-

trivial user base, with

customers from a wide

spectrum of industries,

ranging from traditional

paper mills (Clairefontaine,

Ibema, Blue Paper, Kipaş,

Fiskeby) to highly

specialised film companies

(Raven, Victrex) and

converting operations with

printing lines (Elocoat and

Elopak). Inevitably, this

broad range of uses in

multiple continents has

been stretching the

system’s and Greycon’s

delivery capabilities

(mostly in a good way).

One of the organisational

changes that we are

making is to appoint a

Lead Developer for each

GreyconMill project. This

position aims to manage

the release cycle for each

customer and also carries

the authority to approve

small enhancements

without recourse to others.

So, Elena Mantikou will be

doing this for Kipaş, Johan

Eliasson for Blue Paper and

Nikos Fosteris for Raven.

would round the linear

length of patterns to a

user-specified multiple.

In addition to this, you

can now apply diameter

rounding, e.g. to

1" (imperial units).

Online Updates of

Manuals & Help Files

We have extended the

technology, announced

in 7.9, of online updates

of the language file to the

manuals (Full and Quick

Start) and the associated

help file.

As before, you will need

to ensure your firewall

does not block access to

www.greycon.com to

allow the version check

to take place.

Miscellaneous

443455 sample runs

We have removed

the Machine Selection

button in the order

grid, because its

purpose has been

superseded by the

availability of route

logic.

The stock grid now

also displays the

Allocated and the

Remaining Quantity.

The multi-constant

algorithm assumes

that jumbo reel stock

can be spliced

together.

X-Trim Improvements in 8.0 The 8.0 release contains:

Charting Functionality

Charting is the term

DuPont (US) uses to

describe what we

traditionally call trim

optimisation. See page 9.

Gurobi Library

See below for the quality

of solutions and on the

next page (which also

contains a description of

the various test suites

used to validate

behaviour) for the

computational aspects.

Diameter Rounding for

Variable-Diameter

Problems

In the past an optional

post-solution phase

Page 2 GreyLetter

Who is Gurobi?

Gurobi is a relatively new

entrant in the field of

optimisation software, but

its founders Zonghao Gu,

Edward Rothberg, &

Robert Bixby, have a long

and distinguished track

record, including with

CPLEX, a company later

on acquired by Ilog, which

was acquired in turn by

IBM.

One of the key

architectural differences

of the Gurobi library is

that it has been

engineered from the

ground up for multi-core

computers.

Missing

Algorithms

Two relatively

obscure

algorithms, the

PB and Landau

algorithms

have not yet

been ported to

new library.

Test Suite 7.9 8.0 Difference

TS1—Constant-diameter 92,932,424 92,847,974 -0.09%

TS2– Performance 2,189,106 2,173,880 -0.70%

Total 95,121,530 95,021,854 -0.10%

X-Trim Objective Function in 8.0 The objective function correlates (but not simply) with waste. The improvement is

very small on small problems and greater on difficult ones. The table below shows

the sum of the objective function values for the final solution:

Test Suite 7.9 8.0 Difference

TS1—Constant-diameter 2,509 2,500 -0.36%

TS2– Performance 903 869 -3.91%

Total 3,412 3,369 -1.28%

X-Trim Physical Pattern Count in 8.0 The improvement is very small on small problems but noticeable on difficult ones.

The table shows the total number of physical patterns for each test suite:

February 2014 Page 3

Computational Aspects for X-Trim in 8.0 The Gurobi library

exhibits significant

differences in behaviour

compared to its

predecessor. The overall

summary is that it is

somewhat slower for

problems taking less than

5 seconds and

significantly faster for

larger problems.

As always, the

performance on any one

individual instance may

be worse or better.

Inevitably, with the size

of Greycon’s various test

suites, there will be cases

like this.

Memory

In terms of

computational

performance the Gurobi

library included in the 8.0

release is, like its

predecessor , a 32-bit

component (and will

therefore run

transparently in a 64-bit

environment). This

implies that a maximum

of 2 GB of memory is

available to the optimiser.

However, this means

that, in some cases where

a high core count is used,

Unit Test Evolution

it will report “insufficient

memory”. If this occurs,

the simple work-around

is to reduce the core

count.

Core Count

There is no limit to the

maximum core count. We

have tested it internally

with up to 8 cores.

The previous library, for

reasons we never quite

understood, would never

reach 100% CPU

utilisation when the user

specified the maximum

possible core count.

On the other hand

Gurobi does. This is a

good thing, because it

implies maximum

computational resources

are brought to bear on

the problem at hand.

This does have

implications on server-

based installations,

because it is more

possible for one user to

disrupt the others. We

remind our readers

however that a work-area

-specific maximum core

count can be imposed,

affecting all users.

Speed

The computational speed

differences between 8.0

and the previous version

are shown, for 3 different

test suites, at the bottom

of the page. The test

suites, which are

intended for different

purposes, have the

following characteristics:

Constant-diameter is a

collection of 596 small

problems, typically

demonstrating obscure

aspects; fixes to any

algorithm bugs

typically result in

additions to this suite.

The performance test

suite contains 48

difficult problems,

painstakingly collected

over the years from our

users and selected for

their difficulty; this is

the most interesting

computationally of

course.

Sample runs (455) are

those shipped with the

product.

The table below shows

total time in seconds.

64-bit

In the longer term, we

plan to release a twin-

mode build. This means

that, under a 64-bit

operating system, the

system will operate in 64-

bit mode and therefore

use more memory—and

therefore be faster. This

benefit will only be

available under a 64-bit

operating system and the

lesson therefore is that

you should plan to

migrate to such an

operating system, if not

already there.

Test Suite 7.9 8.0 Difference

TS1—Constant-diameter 451 550 +18%

TS2– Performance 3,528 2,915 -21%

TS3– Sample runs 2,153 1,797 -20%

Total 6,132 5,262 -17%

Page 4 GreyLetter

New Projects

Georgia-Pacific

Georgia-Pacific has joined

the Greycon family with a

purchase of X-Trim for

twelve sites in North

America. The

Containerboard and

Bleached Board Divisions

are replacing two trim

optimization systems

from Greycon

competitors. With this

purchase, Greycon’s

presence in the NA

packaging and

containerboard market

exceeds 70% of capacity.

The consideration to

replace two long standing

systems that were heavily

embedded in their

systems required an

extremely rigorous and

thorough investigation.

Significant financial

justification for change

was a requirement

upfront. Both divisions

conducted independent

pilots to compare the

results of their current

trim optimization system

with Greycon’s X-Trim.

New Projects Cont. p.5

Editing Trim Solutions in opt-Studio 8.0

Simple edits to solutions

already released are now

allowed (no need to mark

for re-trimming).

Just open the released

solution, make the

changes and release again

Stock Compatibility in opt-Studio 8.0 You can use a formula to model what stock items can be used as input to a task:

This expression says that grade

and basis weight must match

and that the caliper can differ by

at most 10 microns

Physical Patterns Display in opt-Studio 8.0

New shortcut available

here, if complex

changes are needed

Logical patterns 2 and 3

displayed as one

When allocating stock you can

show all the items or only the

compatible ones

Only simple changes

allowed for released

solutions

February 2014 Page 5

Variable-diameter Algorithm in 8.0 Due to different

modelling capabilities

in Gurobi, a

completely new model

was created for

variable-diameter

problems. The new

model is:

stricter about over-

and under-makes;

you may have to

increase these to get

equivalent / better

solutions. An easy way

to do this is via the run

-level Incremental

Tolerance.

less likely to report

“Tree dimension

exceeded”

For those interested in

details, the previous

version enforced the

pattern diameter limits

through the tree search;

Film Charting in 8.0

with this approach

specific constraints (rows

in the LP structure) were

unnecessary. This

approach is not possible

in Gurobi, but the

surprising thing is that

adding such constraints

(and there are lots) does

not adversely affect the

computational

performance of the

algorithm.

Working in

conjunction with the

Circleville (Ohio, USA)

plant of DuPont, we

have developed some

complicated but

interesting new

functionality, called

charting.

This arises because the

material is so valuable

that it gives rise to

some “unusual”

cutting scenarios. For

instance, a single slitting

pattern may extend

across multiple stock

items, even when they

are of different width (as

the screenshot below

shows).

Also possible is to return

material to stock (for

future use) both width-

wise and length-wise.

Since all such charting is

from stock reels, it is of

course necessary to take

account of any material

defects.

The number of orders in

this charting scenario is

very small, rendering the

optimisation capabilities

less valuable (and so

we’ve left them for a

future date).

The new charting functionality is

triggered by a new run-level

parameter called Algorithm Mode.

Victrex

This leading global

manufacturer of high

performance polymers,

has placed an order for

the implementation of

GreyconMill and opt-

Studio for its APTIV®

Films division in the

UK. The focus of the

project is on production

tracking, quality and

traceability while

providing the

foundation to

streamline the planning

and the logistics

process. The go-live is

scheduled for August

2014 and our colleague

David Ingham (assigned

as the lead consultant to

this project) will feel at

home after some

extensive travelling

abroad over the past

year.

APTIV® film is a high

performance PEEK film

with lightweight

properties making it a

unique component for

various parts of mobile

devices (imagine the

demand with 1 billion

units of smartphone

sold in 2013!) or with

flame retardant

properties making it a

unique choice for

aircraft insulation

systems. This material

sells at a price / T well

into six figures (UK£), or

1,000 times the price of

some of our other

clients’ products!

GreyconMill Core Cutting & Other Interfaces

Page 6 GreyLetter

GreyconMill Speed

Improvements

During the last couple

of months of 2013, some

customers reported a

slow-down in the

perceived speed of

GreyconMill.

It turned out that this

was due to some

mysterious interaction

related to networking

performance in a

specific virtual machine

environment.

In the process however,

we speeded up

common transactions

in GreyconMill by

around 30%. The steps

were:

GreyconMill now contains

a new capability, to create

warehouse requests.

This is for instances such

as at Kipaş, where the

warehouse is remote from

the shipping dock. In

order to make up a

particular truck load it

may therefore be

necessary to marshal

material from different

sources. This module

recognises essentially

three such sources, (a)

work in progress, (b)

specific stock items (e.g.

specific reels) or (c)

generic stock (e.g. reels

with specific

characteristics).

Warehouse Request Module

Step Time (s)

Baseline 69.0

Reload Authenti- 62.4

Missing Indexes 55.0

Clustered Tables + 53.5

Precompiled Que- 51.0

Cached Settings 48.5

Saving 30%

The new mill at Kipaş will

have an automated core

cutter and therefore

GreyconMill now supports

such

machines.

The operator can request

cores for all the sets of a

pattern, or a subset.

If the core cutting

equipment supports it, the

status of the cores is

presented to the operator.

In addition, the slitter

operator can now position

the trim waste anywhere

(i.e. not necessarily at one

of the edges). This gives

an opportunity to

minimise waste by placing

this on top of a defect.

In interface-related work,

GreyconMill 2.5 SR2 has a

new interface so that an

external system (typically

an ERP), can change any

inventory item, such as

location and condition.

Finally the label printing

module now allows an

external system to request

a label to be printed to a

specific printer.

Release 2.5 SR2 also

includes updates to the

mobile client.

The operators can view

and change the condition

of any item in the

inventory. The mobile

inventory module can now

manage defect

information (as shown on

the right).

GreyconMill Mobile Client

Core Cutting

February 2014 Page 7

Effort in 8.0

The adoption of the

Gurobi library has

required a revamp of the

licensing approach

because of the different

requirements of Gurobi

itself.

Installing Greycon Suite

8.0 or GreyconMill 2.5SR2

will require a new set of

copy control activation

files.

These are obtained in

exactly the same way as

before, namely by

running the Copy

Control Wizard from the

Greycon Administrator

utility.

Copy Control in GS 8.0 and GM 2.5SR2

Releases

The 8.0 Release Notes

can be found in their

usual place (registration

required).

We plan to release 8.1 in

July 2014.

XPRESS

This is the name of the

library being replaced

by Gurobi.

The replacement means

that previous versions of

our applications, which

contain XPRESS, will

not have this

component updated any

further. This poses little

technical risk, as we

have been using the

same version of XPRESS

for over 5 years now

(and in fact, the

unavailability of newer

versions that satisfied

our criteria was a

further reason for

adopting Gurobi).

In all other respects,

support for previous

versions will continue as

outlined in the table on

the left.

7.8 7.9 8.0 8.1

Release Jun 2013 Nov 2013 Feb 2014 Jul 2014

No enhancements Dec 2013 May 2014 Aug 2014 Jan 2015

No changes Jun 2014 Nov 2014 Feb 2015 Jul 2016

No support Jun 2016 Nov 2016 Feb 2017 Jul 2018

In the past, two files were

supplied by Greycon for

this. To these two a third

has been added, which

holds the Gurobi license.

This Gurobi license is a

perpetual one, i.e. has no

expiry date.

In pilot installations the

migration has proved

very smooth.

7 Calico House,

Plantation Wharf,

London SW11 3TN.

Phone: +44 20 7978 0700

E-mail: cng@greycon.com

In November Greycon celebrated its 28th anniversary.

Our systems are now installed in over 400 plants

world-wide, in 41 countries.

Win an Apple iPod Touch 32GB 5th Generation.

Open to users sending us

suggestions for improvements,

which are adopted (the key for

an enhancement to be

adopted is for it to have a high

value / development effort

ratio). For this round, please

send your entries to Jari by

June 15th.

Sign of the Times

Kipaş Kağıt in Turkey has started the

pulpers for its new paper machine, the

production planning is being prepared

in opt-Studio and we expect the first

Jumbo roll turn up in the next couple

of days. This will mark the go-live of

opt-Studio and GreyconMill in an

entirely green-field and highly

automated plant. More details in the

next newsletters.

Update on Kipaş

Well done!

Our Vipul Soneji (senior

consultant in our offices in the

USA) is proud Coach of

TechnoPandas, a team of young

robotics enthusiasts from the

Fulton Sunshine Academy

Elementary School. Vipul started

coaching because of his

daughter’s interest in robotics at

age 7. Team TechoPandas was

awarded the Championship

Award at the FIRST Lego League

(FLL) State Championship held in

Athens, GA on 1st February 2014.

Techno Pandas will represent

Georgia in St. Louis in April in

FLL World Festival, a robotics

competition held annually all over

the world. Greycon sends its

congratulations and wishes the

team all the best for the future!

What’s Coming Next

For the trim optimisation, we are

working on an enhancement (from

Fiskeby) to optimise the addition of

(expensive) sizing to allow inter-mixing

of grades. We may be able to spend

some on the pattern reduction.

opt-Studio will shortly have a major

improvement in block scheduling

optimisation, it will be able to handle

two stage operations, e.g. PM-Coater.

In GreyconMill, we are revamping the

label printing architecture and

migrating to the latest version of

BarTender. We are also planning to

add a standard benchmark, so we can

track performance over time.

This sign was recently seen at a Greycon

customer’s plant in Germany, obviously a

reflection of when, in the German miracle

after the war, the workers’ knowledge of

German could not be taken for granted…

Even better, the Greek version (last) is

more ancient Greek than modern.