topic Simplify an algebraic equation in SAS Programming

Simplify an algebraic equation

cosimodc — Mon, 07 May 2018 12:27:36 GMT

Hi All,

is possible to simplify algebric equation?

I have a character variable with a equation:

"x+2+5+2x+3"

I would create a new variable

"3x+10"

Re: Simplify Equation

Reeza — Fri, 04 May 2018 15:13:39 GMT

What is the question you need help with then?

You can find basic tutorials here:

http://video.sas.com/category/videos/sas-analytics-u

Including this one on creating new variables:

http://video.sas.com/detail/videos/sas-analytics-u/video/4573023399001/creating-a-new-column-in-sas?autoStart=false

@cosimodc wrote:

Hi All,

is possible to simplify algebric equation?

I have a character variable with a equation:

"x+2+5+2x+3"

I would create a new variable

"3x+10"

Re: Simplify Equation

cosimodc — Fri, 04 May 2018 17:02:36 GMT

I want to minimize length a variable which contains a equation.

For example:

data test;

a=x+3x+5x+10*2+4x+10x+x**2+20x;

run;

data new;

b=x**2+43x+20;

run;

Is possible?

Re: Simplify Equation

ballardw — Fri, 04 May 2018 17:13:15 GMT

@cosimodc wrote:

I want to minimize length a variable which contains a equation.

For example:

data test;

a=x+3x+5x+10*2+4x+10x+x**2+20x;

run;

data new;

b=x**2+43x+20;

run;

Is possible?

Possible yes.

How much experience to you have writing compilers that parse code? Which is in effect what you are requesting. You would have to specify exactly every type of function and the reduction rule and I am afraid that introducing () in to the equations means the logic is going to be extremely complex.

Consider

((x+3x+5x+10)*2+4x+10x+x)**2+20x

How are you using these things such that the length is a critical issue?

Re: Simplify Equation

Reeza — Fri, 04 May 2018 18:56:12 GMT

I probably woudn't use SAS for that. Wolfram Alpha can do that and I *think* it has an API call, but it may be a paid service.

Re: Simplify Equation

Rick_SAS — Fri, 04 May 2018 20:24:34 GMT

As someone mentioned, SAS is primarily a numerical language. If you are looking for symbolic computations such as simplifying an algebraic expression, Wolfram Alpha or other symbolic software would be a better choice.

If you want to find the value of x that minimizes or maximizes an expression, then you are solving an optimization problem, and SAS has many ways to numerically optimize equations, including PROC NLIN and NLMIXED (SAS/STAT), PROC IML (SAS/IML), and PROC OPTMODEL (SAS/OR).