====== Factor ======
----

====Description====
  * ''Factor'' factors a symbolic polynomial over the integers.


  * ''Factor'' applies only to scalar parts of expressions.


  * ''Factor'' applies only to the top algebraic level in an expression.


  * ''Factor'' tries to factor all scalar combinations of tensors (like ''k_a*k^a''), which it treats as independent variables. ''%%Factor[[FactorScalars: false]]%%'' will apply only to symbolic expressions, which contain no any indexed variables.

====Examples====
----
Factor a multivariate polynomial:
<sxh groovy; gutter: false>
def t = '2*x**3*y - 2*a**2*x*y - 3*a**2*x**2 + 3*a**4'.t
println Factor >> t
</sxh>
<sxh plain; gutter: false>
   > (x+a)*(x-a)*(-3*a**2+2*y*x)
</sxh>

----

Factor scalar parts in tensorial expression:
<sxh groovy; gutter: false>
def t = '(a+b)**4*F_mn + (x**6-y**6)*R_mn'.t
println Factor >> t
</sxh>
<sxh plain; gutter: false>
   > (a+b)**4*F_mn+(x+y)*(x-y)*(x*y+x**2+y**2)*(-x*y+x**2+y**2)*R_mn
</sxh>

----

Factor expression that contains scalar combinations:
<sxh groovy; gutter: true>
def t = '(a+b)**2*f_m*f^m + (a**2 - b**2)*f_a*f^a*f_b*f^b'.t
println Factor >> t
</sxh>
<sxh plain; gutter: false>
   > (a+b+(a-b)*f_{m}*f^{m})*(a+b)*f_{a}*f^{a}
</sxh>
Do not factor "tensorial" scalars:
<sxh groovy; gutter:  true; first-line: 3>
println Factor[[FactorScalras:false]] >> t
</sxh>
<sxh plain; gutter: false>
   > (a+b)**2*f_{m}*f^{m}-(b+a)*(b-a)*f_{a}*f^{a}*f_{b}*f^{b}
</sxh>
----

====See also====
  * Related guides: [[documentation:guide:applying_and_manipulating_transformations]], [[documentation:guide:list_of_transformations]]
  * Related transformations: [[documentation:ref:expand]]
  * JavaDocs: [[http://api.redberry.cc/redberry/1.1.9/java-api/cc/redberry/core/transformations/factor/FactorTransformation.html|FactorTransformation]]
  * Source code: [[https://bitbucket.org/redberry/redberry/src/tip/core/src/main/java/cc/redberry/core/transformations/factor/FactorTransformation.java|FactorTransformation.java]]