I'm working on matrix transformations using arrays, but nothing goes quite
as planned. The simplest example is transposing a 2d array:

////////////////////////////////////////////////////////////
#macro transp(array1)
     #local a1=dimension_size(array1,1);
     #local a2=dimension_size(array1,2);
     #local i=0;
     #local j=0;
     #declare temp1= array[a2][a1];
     #while (i<=a2-1)
           #while (j<=a1-1)
                  #declare temp1[i][j]=array1[j][i];
                  #local j=j+1;
           #end
           #local i=i+1;
     #end
#end

camera {location -8*z look_at 0}

light_source{<0,10,-10> rgb 1}

#declare ar1=array[3][2] {{1,0},{1,-1},{0,5}};
transp(ar1)
/////////////////////////////////////////////////////////////////

All good till now, I think, but when I try to visualise the result with the
following routine, I only get the first row. If I change the #while's in
the macro, so that i and j start from their highest values and go to 0,
only the last row is rendered. If I add a third dimension in the array,
only the values on a single spine are rendered. Any ideas on what I'm doing
wrong? I have
searched the newsgroup but I haven't seen many examples of nested #while
with arrays, so I'm inclined to think it's something to do with that. Pov
version is 3.61c for Windows.

///////////////////////////////////////////////////////////
#declare i1=0;
#declare j1=0;
union{
#while (i1<=dimension_size(temp1,1)-1)
      #while (j1<=dimension_size(temp1,2)-1)
             text{ttf "timrom.ttf"
                      str(temp1[i1][j1],1,0) 0.1,0 pigment {rgb 1}
              translate <(j1-1)*2,1-(i1-1),0>
              }
        #declare j1=j1+1;
        #end
    #declare i1=i1+1;
#end
}
//////////////////////////////////////////////////////////

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