7.107 bug in matrixplot coloring, Maple 4 to Maple 8 (10.3.00)

7.107.1 Thom Mulders

I want to do a matrixplot and let the color of the bars depend on the value of the matrix entry that is plotted.

I would expect to do this as follows:

A:=linalg[matrix]([[1,2,3],[1,5,6]]); 
col:=proc(x,y) A[x,y]/7 end; 
with(plots): 
matrixplot(A,heights=histogram,axes=frame,style=patch,color=col);
 

The graph I get gives the same color for the bars corresponding to the entries (1,1) and (2,2) but not for the bars corresponding to the entries (1,1) and (2,1) (what I expect).

7.107.2 Carl Devore(25.4.02)

The order that the colors are generated for the histogram plot is transposed from the order that the bars are generated. In Maple 7, you can see this in lines 59 and 67 of procedure `plots/matrixplot`.

In earlier versions of Maple, the procedure is named `plots/matplot`. In Maple 5 & 6, the relevant lines are 39 & 47. In Maple 4, lines 38 & 46.

Since this bug would have been so trivial to fix, and you wrote the above over two years ago, it seems that no-one at WMI who is in a position to do something about these bugs is actually doing anything.