ENH: Added derivative calculation.
ENH: Added derivative calculation.

hendradarwin/VTK,jeffbaumes/jeffbaumes-vtk,daviddoria/PointGraphsPhase1,jmerkow/VTK,collects/VTK,SimVascular/VTK,mspark93/VTK,demarle/VTK,candy7393/VTK,spthaolt/VTK,arnaudgelas/VTK,msmolens/VTK,Wuteyan/VTK,gram526/VTK,hendradarwin/VTK,sankhesh/VTK,sankhesh/VTK,arnaudgelas/VTK,spthaolt/VTK,aashish24/VTK-old,gram526/VTK,cjh1/VTK,biddisco/VTK,jeffbaumes/jeffbaumes-vtk,SimVascular/VTK,SimVascular/VTK,aashish24/VTK-old,sgh/vtk,msmolens/VTK,spthaolt/VTK,keithroe/vtkoptix,sumedhasingla/VTK,mspark93/VTK,jmerkow/VTK,spthaolt/VTK,gram526/VTK,sankhesh/VTK,arnaudgelas/VTK,aashish24/VTK-old,keithroe/vtkoptix,sumedhasingla/VTK,sgh/vtk,naucoin/VTKSlicerWidgets,johnkit/vtk-dev,jeffbaumes/jeffbaumes-vtk,berendkleinhaneveld/VTK,msmolens/VTK,jeffbaumes/jeffbaumes-vtk,spthaolt/VTK,aashish24/VTK-old,berendkleinhaneveld/VTK,arnaudgelas/VTK,msmolens/VTK,keithroe/vtkoptix,johnkit/vtk-dev,msmolens/VTK,jeffbaumes/jeffbaumes-vtk,cjh1/VTK,ashray/VTK-EVM,sgh/vtk,keithroe/vtkoptix,johnkit/vtk-dev,collects/VTK,naucoin/VTKSlicerWidgets,Wuteyan/VTK,demarle/VTK,daviddoria/PointGraphsPhase1,mspark93/VTK,johnkit/vtk-dev,cjh1/VTK,johnkit/vtk-dev,gram526/VTK,sgh/vtk,gram526/VTK,hendradarwin/VTK,ashray/VTK-EVM,spthaolt/VTK,sgh/vtk,gram526/VTK,mspark93/VTK,cjh1/VTK,hendradarwin/VTK,naucoin/VTKSlicerWidgets,berendkleinhaneveld/VTK,sankhesh/VTK,jmerkow/VTK,mspark93/VTK,sumedhasingla/VTK,ashray/VTK-EVM,collects/VTK,keithroe/vtkoptix,demarle/VTK,keithroe/vtkoptix,jmerkow/VTK,biddisco/VTK,hendradarwin/VTK,jmerkow/VTK,mspark93/VTK,naucoin/VTKSlicerWidgets,sankhesh/VTK,hendradarwin/VTK,sumedhasingla/VTK,Wuteyan/VTK,cjh1/VTK,naucoin/VTKSlicerWidgets,collects/VTK,daviddoria/PointGraphsPhase1,biddisco/VTK,biddisco/VTK,sankhesh/VTK,ashray/VTK-EVM,jeffbaumes/jeffbaumes-vtk,berendkleinhaneveld/VTK,collects/VTK,candy7393/VTK,SimVascular/VTK,Wuteyan/VTK,cjh1/VTK,msmolens/VTK,candy7393/VTK,berendkleinhaneveld/VTK,biddisco/VTK,SimVascular/VTK,spthaolt/VTK,SimVascular/VTK,candy7393/VTK,gram526/VTK,SimVascular/VTK,ashray/VTK-EVM,Wuteyan/VTK,candy7393/VTK,jmerkow/VTK,collects/VTK,ashray/VTK-EVM,arnaudgelas/VTK,biddisco/VTK,sumedhasingla/VTK,arnaudgelas/VTK,msmolens/VTK,candy7393/VTK,jmerkow/VTK,SimVascular/VTK,johnkit/vtk-dev,sumedhasingla/VTK,mspark93/VTK,demarle/VTK,naucoin/VTKSlicerWidgets,johnkit/vtk-dev,daviddoria/PointGraphsPhase1,mspark93/VTK,sumedhasingla/VTK,candy7393/VTK,sankhesh/VTK,msmolens/VTK,aashish24/VTK-old,Wuteyan/VTK,keithroe/vtkoptix,aashish24/VTK-old,demarle/VTK,gram526/VTK,sumedhasingla/VTK,berendkleinhaneveld/VTK,ashray/VTK-EVM,berendkleinhaneveld/VTK,sgh/vtk,biddisco/VTK,candy7393/VTK,demarle/VTK,ashray/VTK-EVM,Wuteyan/VTK,demarle/VTK,keithroe/vtkoptix,hendradarwin/VTK,daviddoria/PointGraphsPhase1,demarle/VTK,sankhesh/VTK,daviddoria/PointGraphsPhase1,jmerkow/VTK