<s>
TK	B-Application
Solver	I-Application
(	O
originally	O
TK	B-Application
!	I-Application
Solver	I-Application
)	O
is	O
a	O
mathematical	O
modeling	O
and	O
problem	O
solving	O
software	O
system	O
based	O
on	O
a	O
declarative	B-Language
,	O
rule-based	O
language	O
,	O
commercialized	O
by	O
Universal	O
Technical	O
Systems	O
,	O
Inc	O
.	O
</s>
<s>
Invented	O
by	O
Milos	O
Konopasek	O
in	O
the	O
late	O
1970s	O
and	O
initially	O
developed	O
in	O
1982	O
by	O
Software	O
Arts	O
,	O
the	O
company	O
behind	O
VisiCalc	B-Application
,	O
TK	B-Application
Solver	I-Application
was	O
acquired	O
by	O
Universal	O
Technical	O
Systems	O
in	O
1984	O
after	O
Software	O
Arts	O
fell	O
into	O
financial	O
difficulty	O
and	O
was	O
sold	O
to	O
Lotus	O
Software	O
.	O
</s>
<s>
Konopasek	O
's	O
goal	O
in	O
inventing	O
the	O
TK	B-Application
Solver	I-Application
concept	O
was	O
to	O
create	O
a	O
problem	O
solving	O
environment	O
in	O
which	O
a	O
given	O
mathematical	O
model	O
built	O
to	O
solve	O
a	O
specific	O
problem	O
could	O
be	O
used	O
to	O
solve	O
related	O
problems	O
(	O
with	O
a	O
redistribution	O
of	O
input	O
and	O
output	O
variables	O
)	O
with	O
minimal	O
or	O
no	O
additional	O
programming	O
required	O
:	O
once	O
a	O
user	O
enters	O
an	O
equation	O
,	O
TK	B-Application
Solver	I-Application
can	O
evaluate	O
that	O
equation	O
as	O
iswithout	O
isolating	O
unknown	O
variables	O
on	O
one	O
side	O
of	O
the	O
equals	O
sign	O
.	O
</s>
<s>
The	O
New	O
York	O
Times	O
described	O
TK	B-Application
Solver	I-Application
as	O
doing	O
"	O
for	O
science	O
and	O
engineering	O
what	O
word	O
processing	O
did	O
for	O
corporate	O
communictions	O
 [ sic ] 	O
and	O
calc	O
packages	O
did	O
for	O
finance.	O
"	O
</s>
<s>
Lotus	O
,	O
which	O
had	O
acquired	O
Software	O
Arts	O
,	O
including	O
TK	B-Application
Solver	I-Application
,	O
in	O
1984	O
sold	O
its	O
ownership	O
of	O
the	O
software	O
to	O
Universal	O
Technical	O
Systems	O
less	O
than	O
two	O
years	O
later	O
.	O
</s>
<s>
TK	B-Application
Solver	I-Application
's	O
core	O
technologies	O
are	O
a	O
declarative	B-Language
programming	I-Language
language	I-Language
,	O
algebraic	O
equation	O
solver	O
,	O
an	O
iterative	O
equation	O
solver	O
,	O
and	O
a	O
structured	O
,	O
object-based	O
interface	O
,	O
using	O
a	O
command	O
structure	O
.	O
</s>
<s>
The	O
interface	O
uses	O
toolbars	O
and	O
a	O
hierarchal	O
navigation	O
bar	O
that	O
resembles	O
the	O
directory	O
tree	O
seen	O
on	O
the	O
left	O
side	O
of	O
the	O
Windows	B-Protocol
Explorer	I-Protocol
.	O
</s>
<s>
The	O
declarative	B-Language
programming	I-Language
structure	O
is	O
embodied	O
in	O
the	O
rules	O
,	O
functions	O
and	O
variables	O
that	O
form	O
the	O
core	O
of	O
a	O
mathematical	O
model	O
.	O
</s>
<s>
Unlike	O
a	O
spreadsheet	O
or	O
imperative	B-Application
programming	I-Application
environment	O
,	O
the	O
rules	O
can	O
be	O
in	O
any	O
order	O
or	O
sequence	O
and	O
are	O
not	O
expressed	O
as	O
assignment	O
statements	O
.	O
</s>
<s>
"	O
A	O
+	O
B	O
=	O
C	O
/	O
D	O
"	O
is	O
a	O
valid	O
rule	O
in	O
TK	B-Application
Solver	I-Application
and	O
can	O
be	O
solved	O
for	O
any	O
of	O
its	O
four	O
variables	O
.	O
</s>
<s>
A	O
TK	B-Application
Solver	I-Application
model	O
can	O
include	O
up	O
to	O
32,000	O
rules	O
,	O
and	O
the	O
library	O
that	O
ships	O
with	O
the	O
current	O
version	O
includes	O
utilities	O
for	O
higher	O
mathematics	O
,	O
statistics	O
,	O
engineering	O
and	O
science	O
,	O
finances	O
,	O
and	O
programming	O
.	O
</s>
<s>
A	O
database	O
of	O
unit	O
conversion	O
factors	O
also	O
ships	O
with	O
TK	B-Application
Solver	I-Application
,	O
and	O
users	O
can	O
add	O
,	O
delete	O
,	O
or	O
import	O
unit	O
conversions	O
in	O
a	O
way	O
similar	O
to	O
that	O
for	O
rules	O
.	O
</s>
<s>
TK	B-Application
Solver	I-Application
has	O
three	O
ways	O
of	O
solving	O
systems	O
of	O
equations	O
.	O
</s>
<s>
A	O
list	O
solver	O
feature	O
allows	O
variables	O
to	O
be	O
associated	O
with	O
ranges	O
of	O
data	O
or	O
probability	O
distributions	O
,	O
solving	O
for	O
multiple	O
values	O
,	O
which	O
is	O
useful	O
for	O
generating	O
tables	O
and	O
plots	O
and	O
for	O
running	O
Monte	B-Algorithm
Carlo	I-Algorithm
simulations	I-Algorithm
.	O
</s>
<s>
TK	B-Application
Solver	I-Application
includes	O
roughly	O
150	O
built-in	O
functions	O
:	O
mathematical	O
,	O
trigonometric	O
,	O
Boolean	O
,	O
numerical	O
calculus	O
,	O
matrix	O
operations	O
,	O
database	O
access	O
,	O
and	O
programming	O
functions	O
,	O
including	O
string	O
handling	O
and	O
calls	O
to	O
externally	O
compiled	O
routines	O
.	O
</s>
<s>
Users	O
may	O
also	O
define	O
three	O
types	O
of	O
functions	O
:	O
declarative	B-Language
rule	O
functions	O
;	O
list	O
functions	O
,	O
for	O
table	O
lookups	O
and	O
other	O
operations	O
involving	O
pairs	O
of	O
lists	O
;	O
and	O
procedure	O
functions	O
,	O
for	O
loops	O
and	O
other	O
procedural	O
operations	O
which	O
may	O
also	O
process	O
or	O
result	O
in	O
arrays	O
(	O
lists	O
of	O
lists	O
)	O
.	O
</s>
<s>
TK	B-Application
Solver	I-Application
is	O
also	O
the	O
platform	O
for	O
engineering	O
applications	O
marketed	O
by	O
UTS	O
,	O
including	O
Advanced	O
Spring	O
Design	O
,	O
Integrated	O
Gear	O
Software	O
,	O
Interactive	O
Roark	O
’s	O
Formulas	O
,	O
Heat	O
Transfer	O
on	O
TK	O
,	O
and	O
Dynamics	O
and	O
Vibration	O
Analysis	O
.	O
</s>
<s>
Tables	O
,	O
plots	O
,	O
comments	O
,	O
and	O
the	O
MathLook	O
notation	O
display	O
tool	O
can	O
be	O
used	O
to	O
enrich	O
TK	B-Application
Solver	I-Application
models	O
.	O
</s>
<s>
Models	O
can	O
be	O
linked	O
to	O
other	O
components	O
with	O
Microsoft	O
Visual	B-Language
Basic	I-Language
and	O
.NET	B-Application
tools	O
,	O
or	O
they	O
can	O
be	O
web-enabled	O
using	O
the	O
RuleMaster	O
product	O
or	O
linked	O
with	O
Excel	B-Application
spreadsheets	O
using	O
the	O
Excel	B-Application
Toolkit	O
product	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
DesignLink	O
option	O
linking	O
TK	B-Application
Solver	I-Application
models	O
with	O
CAD	O
drawings	O
and	O
solid	O
models	O
.	O
</s>
<s>
In	O
the	O
premium	O
version	O
,	O
standalone	O
models	O
can	O
be	O
shared	O
with	O
others	O
who	O
do	O
not	O
have	O
a	O
TK	O
license	O
,	O
opening	O
them	O
in	O
Excel	B-Application
or	O
the	O
free	O
TK	O
Player	O
.	O
</s>
<s>
BYTE	B-Application
in	O
1984	O
stated	O
that	O
"	O
TK	B-Application
!	I-Application
Solver	I-Application
is	O
superb	O
for	O
solving	O
almost	O
any	O
kind	O
of	O
equation	O
"	O
,	O
but	O
that	O
it	O
did	O
not	O
handle	O
matrices	B-Architecture
,	O
and	O
that	O
a	B-Language
programming	I-Language
language	I-Language
like	O
Fortran	B-Application
or	O
APL	B-Language
was	O
superior	O
for	O
simultaneous	O
solution	O
of	O
linear	O
equations	O
.	O
</s>
<s>
By	O
version	O
5.0	O
,	O
TK	B-Application
Solver	I-Application
added	O
Matrix	O
handling	O
functionality	O
.	O
</s>
<s>
Competitive	O
products	O
appeared	O
by	O
mid-1988	O
:	O
Mathsoft	O
's	O
Mathcad	B-Application
and	O
Borland	O
's	O
Eureka	O
:	O
The	O
Solver	O
.	O
</s>
<s>
Dan	O
Bricklin	O
,	O
known	O
for	O
VisiCalc	B-Application
and	O
his	O
Software	O
Arts	O
's	O
initial	O
development	O
of	O
TK	B-Application
Solver	I-Application
,	O
was	O
quoted	O
as	O
saying	O
that	O
the	O
market	O
"	O
was	O
n't	O
as	O
big	O
as	O
we	O
thought	O
it	O
would	O
be	O
because	O
not	O
that	O
many	O
people	O
think	O
in	O
equations.	O
"	O
</s>
