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 documentation:ref:factor [2015/11/21 12:33] documentation:ref:factor [2015/11/21 12:33] (current) Line 1: Line 1: + ====== 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: + + def t = '​2*x**3*y - 2*a**2*x*y - 3*a**2*x**2 + 3*a**4'​.t + println Factor >> t + ​ + + > (x+a)*(x-a)*(-3*a**2+2*y*x) + ​ + + ---- + + Factor scalar parts in tensorial expression: + + def t = '​(a+b)**4*F_mn + (x**6-y**6)*R_mn'​.t + println Factor >> t + ​ + + > (a+b)**4*F_mn+(x+y)*(x-y)*(x*y+x**2+y**2)*(-x*y+x**2+y**2)*R_mn + ​ + + ---- + + Factor expression that contains scalar combinations:​ + + 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 + ​ + + > (a+b+(a-b)*f_{m}*f^{m})*(a+b)*f_{a}*f^{a} + ​ + Do not factor "​tensorial"​ scalars: + + println Factor[[FactorScalras:​false]] >> t + ​ + + > (a+b)**2*f_{m}*f^{m}-(b+a)*(b-a)*f_{a}*f^{a}*f_{b}*f^{b} + ​ + ---- + + ====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]]