plMinMax2dGrid: Find the minimum and
    maximum of a PLFLT matrix of type PLFLT_MATRIX allocated using plAlloc2dGrid
    
| 
	    plMinMax2dGrid
	  ( | f, | 
| nx, | |
| ny, | |
| fmax, | |
| fmin ); | 
    Find the minimum and maximum of a PLFLT matrix of type
    PLFLT_MATRIX allocated using plAlloc2dGrid.
    
f
	  (PLFLT_MATRIXA matrix to find the maximum / minimum of.
nx, ny
	  (PLINT
	  Dimensions of f.
	  
fmax, fmin
	  (PLFLT_NC_SCALAR
	  Returned maximum and minimum values of the matrix
	  f.
	  
This function is used in C examples 8, 11, 20 and 21.