2: #include <petscvec.h>        /*I "petscvec.h" I*/


  7: /*@
  8:     VecContourScale - Prepares a vector of values to be plotted using 
  9:     the PetscDrawTriangle() contour plotter.

 11:     Collective on Vec

 13:     Input Parameters:
 14: +   v - the vector of values
 15: .   vmin - minimum value (for lowest color)
 16: -   vmax - maximum value (for highest color)

 18:    Level: intermediate

 20: .seealso: PetscDrawTensorContour(),PetscDrawTensorContourPatch()

 22: @*/
 23: PetscErrorCode  VecContourScale(Vec v,PetscReal vmin,PetscReal vmax)
 24: {
 25:   PetscScalar    *values;
 27:   PetscInt       n,i;
 28:   PetscReal      scale;


 33:   if (PetscAbsReal(vmax - vmin) < 1.e-50) {
 34:      scale = 1.0;
 35:   } else {
 36:     scale = (245.0 - PETSC_DRAW_BASIC_COLORS)/(vmax - vmin);
 37:   }

 39:   VecGetLocalSize(v,&n);
 40:   VecGetArray(v,&values);
 41:   for (i=0; i<n; i++) {
 42:     values[i] = (PetscReal)PETSC_DRAW_BASIC_COLORS + scale*(values[i] - vmin);
 43:   }
 44:   VecRestoreArray(v,&values);

 46:   return(0);
 47: }