Question: Error in plots/Matrixplot invalid input: convert/Matrix expects its 1st argument to be of type Matrix..

Hello again,

After i execute this code deltaT is no longer a Matrix, can anyone say me why?

(Supposing the first for loop only goes until 8 for instance deltaT remains a Matrix and the plot works so far...)

deltaT :=Matrix(1..19,1..6,fill=1)

 i := 0;
> j := 0;
> interfaceenergy := -1;
> sig := -200*10^6;
> for a from 1 by 1 to 19 do  interfaceenergy:=interfaceenergy+1; i:=i+1; j:=0;
> for b from 1 by 1 to 6 do sig:=sig+200*10^(6);  j:=j+1;
> Temp := fsolve(xi_M(T, sig, interfaceenergy) = anteil, T, T = 50 .. 1000);
> steigung := eval(ableitung, [T = Temp, sigma = sig, UAM = interfaceenergy]);
> deltaT(i,j):=evalf((1/(steigung))*(-1));
> end do;
> end do;

matrixplot(deltaT, axes=boxed)

error... (see headline)

whattype(deltaT)  --  symbol