ParametricDerivatives - Maple Help
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ParametricDerivatives

find the parametric derivatives of a LAVF object

 Calling Sequence ParametricDerivatives( obj) ParametricDerivatives( obj, order= m .. n) ParametricDerivatives( obj, order= m)

Parameters

 obj - a LAVF object m, n - non-negative integers

Description

 • The ParametricDerivatives method finds the parametric derivatives of a LAVF object. The parametric derivatives are returned as a list of functions.
 • The method is front-end to the corresponding method of a LHPDE object. That is, let L be a LAVF object and S be its determining system as a LHPDE object (i.e. S = GetDeterminingSystem(L)), then the call ParametricDerivatives(L) is equivalent to ParametricDerivatives(S). All remaining input arguments will be passed down to its determining system S level. See the method ParametricDerivatives of a LHPDE object for more detail.
 • This method is associated with the LAVF object. For more detail, see Overview of the LAVF object.

Examples

 > $\mathrm{with}\left(\mathrm{LieAlgebrasOfVectorFields}\right):$
 > $\mathrm{Typesetting}:-\mathrm{Settings}\left(\mathrm{userep}=\mathrm{true}\right):$
 > $\mathrm{Typesetting}:-\mathrm{Suppress}\left(\left[\mathrm{\xi }\left(x,y\right),\mathrm{\eta }\left(x,y\right)\right]\right):$

First, construct an indeterminate vector field and a determining system, then construct an LAVF object from them...

 > $V≔\mathrm{VectorField}\left(\mathrm{\xi }\left(x,y\right)\mathrm{D}\left[x\right]+\mathrm{\eta }\left(x,y\right)\mathrm{D}\left[y\right],\mathrm{space}=\left[x,y\right]\right)$
 ${V}{≔}{\mathrm{\xi }}{}\left(\frac{{ⅆ}}{{ⅆ}{x}}\right){+}{\mathrm{\eta }}{}\left(\frac{{ⅆ}}{{ⅆ}{y}}\right)$ (1)
 > $\mathrm{E2}≔\mathrm{LHPDE}\left(\left[\mathrm{diff}\left(\mathrm{\xi }\left(x,y\right),y,y\right)=0,\mathrm{diff}\left(\mathrm{\eta }\left(x,y\right),x\right)=-\mathrm{diff}\left(\mathrm{\xi }\left(x,y\right),y\right),\mathrm{diff}\left(\mathrm{\eta }\left(x,y\right),y\right)=0,\mathrm{diff}\left(\mathrm{\xi }\left(x,y\right),x\right)=0\right],\mathrm{indep}=\left[x,y\right],\mathrm{dep}=\left[\mathrm{\xi },\mathrm{\eta }\right]\right)$
 ${\mathrm{E2}}{≔}\left[{{\mathrm{\xi }}}_{{y}{,}{y}}{=}{0}{,}{{\mathrm{\eta }}}_{{x}}{=}{-}{{\mathrm{\xi }}}_{{y}}{,}{{\mathrm{\eta }}}_{{y}}{=}{0}{,}{{\mathrm{\xi }}}_{{x}}{=}{0}\right]{,}{\mathrm{indep}}{=}\left[{x}{,}{y}\right]{,}{\mathrm{dep}}{=}\left[{\mathrm{\xi }}{,}{\mathrm{\eta }}\right]$ (2)
 > $L≔\mathrm{LAVF}\left(V,\mathrm{E2}\right)$
 ${L}{≔}\left[{\mathrm{\xi }}{}\left(\frac{{ⅆ}}{{ⅆ}{x}}\right){+}{\mathrm{\eta }}{}\left(\frac{{ⅆ}}{{ⅆ}{y}}\right)\right]\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&where}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\left\{\left[{{\mathrm{\xi }}}_{{y}{,}{y}}{=}{0}{,}{{\mathrm{\xi }}}_{{x}}{=}{0}{,}{{\mathrm{\eta }}}_{{x}}{=}{-}{{\mathrm{\xi }}}_{{y}}{,}{{\mathrm{\eta }}}_{{y}}{=}{0}\right]\right\}$ (3)

Now we can find the parametric derivatives of L...

 > $\mathrm{ParametricDerivatives}\left(L\right)$
 $\left[{\mathrm{\eta }}{,}{\mathrm{\xi }}{,}{{\mathrm{\xi }}}_{{y}}\right]$ (4)
 > $\mathrm{ParametricDerivatives}\left(L,\mathrm{order}=0\right)$
 $\left[{\mathrm{\xi }}{,}{\mathrm{\eta }}\right]$ (5)

Compatibility

 • The ParametricDerivatives command was introduced in Maple 2020.
 • For more information on Maple 2020 changes, see Updates in Maple 2020.