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liesymm

 mixpar
 order the mixed partials

 Calling Sequence mixpar(expr)

Parameters

 expr - term involving diff or Diff

Description

 • This routine is part of the liesymm package and is loaded via with(liesymm).
 • Given an expression involving Diff or diff, expr reorder the partials to an address'' ordering so that mixed partials can be recognized as equivalent.

Examples

 > $\mathrm{with}\left(\mathrm{liesymm}\right):$$\mathrm{setup}\left(x,y,z\right):$
 > $\mathrm{mixpar}\left(\frac{{{\partial }}^{2}}{{\partial }y{\partial }x}f\left(x,y\right)\right)$
 $\frac{{{\partial }}^{{2}}}{{\partial }{y}{}{\partial }{x}}{}{f}{}\left({x}{,}{y}\right)$ (1)
 > $\mathrm{mixpar}\left(\frac{{\partial }}{{\partial }y}\left(\frac{{\partial }}{{\partial }x}f\left(x,y\right)\right)\right)$
 $\frac{{{\partial }}^{{2}}}{{\partial }{y}{}{\partial }{x}}{}{f}{}\left({x}{,}{y}\right)$ (2)
 > $\mathrm{mixpar}\left(\frac{{\partial }}{{\partial }x}\left(\frac{{\partial }}{{\partial }y}f\left(x,y\right)\right)\right)$
 $\frac{{{\partial }}^{{2}}}{{\partial }{y}{}{\partial }{x}}{}{f}{}\left({x}{,}{y}\right)$ (3)