The Apply and Unapply commands are used with transformation objects, and are explained on the help pages of these transformation objects.

Transformation objects are created by the Difference and BoxCoxTransform commands. The LogTransform command is a special case of the BoxCoxTransform command.

$\mathrm{with}\left(\mathrm{TimeSeriesAnalysis}\right)\:$

$\mathrm{sales}≔\mathrm{TimeSeries}\left(\left[150\,147\,114\,113\,91\,164\,56\,39\,32\,86\right]\,\mathrm{startdate}=''2010-01-01''\,\mathrm{frequency}=''weekly''\,\mathrm{header}=''Weekly\; Sales''\right)$

$\mathrm{sales}≔\left[\begin{array}{c}\mathrm{Time\; series}\\ \mathrm{Weekly\; Sales}\\ \mathrm{10\; rows\; of\; data:}\\ \mathrm{2010-01-01\; -\; 2010-03-05}\end{array}\right]$

$\mathrm{GetData}\left(\mathrm{sales}\right)\left[..4\right]$

$\left[\begin{array}{c}150.\\ 147.\\ 114.\\ 113.\end{array}\right]$

$\mathrm{log\_sales}≔\mathrm{Apply}\left(\mathrm{LogTransform}\,\mathrm{sales}\right)$

$\mathrm{log\_sales}≔\left[\begin{array}{c}\mathrm{Time\; series}\\ \mathrm{Logarithm\; of\; Weekly\; Sales}\\ \mathrm{10\; rows\; of\; data:}\\ \mathrm{2010-01-01\; -\; 2010-03-05}\end{array}\right]$

$\mathrm{GetData}\left(\mathrm{log\_sales}\right)\left[..4\right]$

$\left[\begin{array}{c}5.01063529409626\\ 4.99043258677874\\ 4.73619844839450\\ 4.72738781871234\end{array}\right]$

$\mathrm{original}≔\mathrm{Unapply}\left(\mathrm{LogTransform}\,\mathrm{log\_sales}\right)$

$\mathrm{original}≔\left[\begin{array}{c}\mathrm{Time\; series}\\ \mathrm{Weekly\; Sales}\\ \mathrm{10\; rows\; of\; data:}\\ \mathrm{2010-01-01\; -\; 2010-03-05}\end{array}\right]$

$\mathrm{GetData}\left(\mathrm{original}\right)\left[..4\right]$

$\left[\begin{array}{c}150.000000000000\\ 147.000000000000\\ 114.000000000000\\ 113.000000000000\end{array}\right]$

$\mathrm{differenced}≔\mathrm{Apply}\left(\mathrm{Difference}\,\mathrm{sales}\right)$

$\mathrm{differenced}≔\left[\begin{array}{c}\mathrm{Time\; series}\\ \mathrm{Weekly\; Sales\; (differenced)}\\ \mathrm{9\; rows\; of\; data:}\\ \mathrm{2010-01-08\; -\; 2010-03-05}\end{array}\right]$

$\mathrm{GetData}\left(\mathrm{differenced}\right)\left[..4\right]$

$\left[\begin{array}{c}\mathrm{-3.}\\ \mathrm{-33.}\\ \mathrm{-1.}\\ \mathrm{-22.}\end{array}\right]$

$\mathrm{original}≔\mathrm{Unapply}\left(\mathrm{Difference}\,\mathrm{differenced}\right)$

$\mathrm{original}≔\left[\begin{array}{c}\mathrm{Time\; series}\\ \mathrm{Weekly\; Sales}\\ \mathrm{9\; rows\; of\; data:}\\ \mathrm{2010-01-08\; -\; 2010-03-05}\end{array}\right]$

$\mathrm{GetData}\left(\mathrm{original}\right)\left[..4\right]$

$\left[\begin{array}{c}147.\\ 114.\\ 113.\\ 91.\end{array}\right]$

The TimeSeriesAnalysis[Apply] and TimeSeriesAnalysis[Unapply] commands were introduced in Maple 18.

For more information on Maple 18 changes, see Updates in Maple 18.