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--- documentation:ref:expandtensors [2015/11/20 20:38]
poslavskysv created
+++ documentation:ref:expandtensors [2015/11/21 12:33] (current)
@@ Line 2: / Line 2: @@
 ----
 ====Description====
-  * ''ExpandTensors'' expands out products leaving unexpended symbolic terms.
+  * ''ExpandTensors'' expands out products of tensors leaving unexpended all symbolic terms.
   * ''ExpandTensors[transformations]'' or ''%%ExpandTensors[[Simplifications: transformations]]%%'' applies ''transformations'' at each level of expand procedure.
-  * ''ExpandTensors[[LeaveScalars: true]]'' will not expand expressions like ''(A_a^a + B_a^a)*(C_b^b + D_b^b)''.
+  * ''%%ExpandTensors[[LeaveScalars: true]]%%'' will not expand expressions like ''(A_a^a + B_a^a)*(C_b^b + D_b^b)''.
 ====Examples====
@@ Line 22: / Line 22: @@
 </sxh>
 <sxh plain; gutter: false>
-   > (1 + x)**4*A_a + (1 + x)**4*B_a
+   > (1 + x)**4 * A_a + (1 + x)**4 * B_a
 </sxh>
-----
 <sxh groovy; gutter: false>
-println Expand >> '(1 + x)**4'.t
+println ExpandTensors >> '(1 + x)**4*(A_a + B_a)*(A^a + B^a)'.t
 </sxh>
 <sxh plain; gutter: false>
-   > x**4+1+4*x**3+6*x**2+4*x
+   > (x+1)**4*B^{a}*B_{a}+2*(x+1)**4*B^{a}*A_{a}+(x+1)**4*A^{a}*A_{a}
 </sxh>
 ----
-<sxh groovy; gutter: false>
-println Expand >> '(x + y)/z'.t
-</sxh>
-<sxh plain; gutter: false>
-   > x/z+y/z
-</sxh>
-----
+Symbolic parts will be kept on all levels:
-''Expand'' relabels dummies when necessary:
 <sxh groovy; gutter: false>
-println Expand >> '(A_m^m + 1)**3'.t
+def t = '((a+b)*(c+d)*(f_a + (k+i)*t_a) + (a + c)*t_a)*(c+r)*((a+b)*f^a + (c+d)*t^a)'.t
+println ExpandTensors >> t
 </sxh>
 <sxh plain; gutter: false>
-   > 3*A_{m}^{m}*A_{a}^{a}+A_{m}^{m}*A_{a}^{a}*A_{b}^{b}+1+3*A_{b}^{b}
+   > (c+r)*(c+d)*(a+b)**2*f_a*f^a + (c+r)*((a+b)*(c+d)*(k+i) +
+          (a + c))*(a+b)*t_a*f^a + (c+r)*(a+b)*(c+d)*(c+d)*f_a*t^a
+          + (c+r)*((a+b)*(c+d)*(k+i) + (a + c))*(c+d)*t_a*t^a
 </sxh>
 ----
+Specify additional simplifications:
-''Expand'' does not go inside functions and denominators; ''ExpandAll'' does:
 <sxh groovy; gutter: false>
-println Expand >> 'f[(x + y)**2]'.t
+def simplify = 'f_a*f^a = a'.t & 'f_a*t^a = b'.t & 't_a*t^a = c'.t
+def t = '(2*(c+a)-164*a)*(f_{a}+t_{a})*f^{a}'.t
+println ExpandTensors[simplify] >> t
 </sxh>
 <sxh plain; gutter: false>
-   > f[(x + y)**2]
+   > a*(-164*a+2*(c+a))+b*(-164*a+2*(c+a))
 </sxh>
-<sxh groovy; gutter: false>
-println ExpandAll >> 'f[(x + y)**2]'.t
-</sxh>
-<sxh plain; gutter: false>
-   > f[x**2 + 2*x*y + y**2]
-</sxh>
 ====See also====
   * Related guides: [[documentation:guide:applying_and_manipulating_transformations]], [[documentation:guide:list_of_transformations]]
   * Related transformations: [[documentation:ref:expand]],  [[documentation:ref:expandall]], [[documentation:ref:expandnumerator]], [[documentation:ref:expanddenominator]]
-  * JavaDocs: [[http://api.redberry.cc/redberry/1.1.8/java-api/cc/redberry/core/transformations/expand/ExpandTensorsTransformation.html|ExpandTensorsTransformation]]
+  * JavaDocs: [[http://api.redberry.cc/redberry/1.1.9/java-api/cc/redberry/core/transformations/expand/ExpandTensorsTransformation.html|ExpandTensorsTransformation]]
   * Source code: [[https://bitbucket.org/redberry/redberry/src/tip/core/src/main/java/cc/redberry/core/transformations/expand/ExpandTensorsTransformation.java|ExpandTensorsTransformation.java]]