====== CollectNonScalars ======
----
====Description====
  * ''CollectNonScalars'' collects terms in sums with same tensorial parts. In contrast to standard Redberry behaviour when factored out tersorial parts with nonzero sized idices, ''CollectNonScalars'' tries to factor out parts with nonzero sized free indices.
====Examples====
----
Collect same tensorial parts:
<sxh groovy; gutter: true>
//by default, B_m will not be factored out
def t = 'A_i*A^i*B_m + B_m'.t
println t
</sxh>
<sxh plain; gutter:false>
   > A_i*A^i*B_m + B_m
</sxh>
<sxh groovy; gutter: true; first-line: 4>
//now will
println CollectNonScalars >> t
</sxh>
<sxh plain; gutter:false>
   > (A_i*A^i + 1)*B_m
</sxh>

----
Another example:
<sxh groovy; gutter: false>
setSymmetric 'R_mn'
println CollectNonScalars >> 'A_t*A^t*R_mn - B_t*B^t*R_nm'.t
</sxh>
<sxh plain; gutter:false>
   > (A_{t}*A^{t}-B_{t}*B^{t})*R_{mn}
</sxh>
----

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