How to repeat a code and build upon previous run's results?

I have a code that runs through a matrix, finds the min, finds min of corresponding supply/demand vectors and does proper subtraction. How do I tell it to just keep looping this for x number of times or until the associated vectors all =zero.

CostsMtx=[16,18,17,20,17;25,27,29,32,28;1.5,1.6,1.7,2,1.8;50,54,56,60,57;60,63,65,68,64];
supply=[800,600,1000,400,100];
demand=[870,435,725,464,406];
mtxsz=size(CostsMtx);
%%%%%%%%%%
tmtx=CostsMtx;
res=zeros(mtxsz);
%%%%%%%%%
R=supply;
D=demand;
x=min(tmtx(tmtx>0));
[Row,Col]=find(tmtx==x);
rm=R(1,Row);
dm=D(1,Col);
    if R(1,Row)==0
        tmtx(Row,Col)=0;
    end
    if D(1,Col)==0
        tmtx(Row,Col)=0;
    end
    if rm<dm
        res(Row,Col)=tmtx(Row,Col)*R(1,Row);
        D(1,Col)=D(1,Col)-R(1,Row);
        R(1,Row)=0;
        tmtx(Row,Col)=0;
    end
    if dm<rm
        res(Row,Col)=tmtx(Row,Col)*D(1,Col);
        R(1,Row)=R(1,Row)-D(1,Col);
        D(1,Col)=0;
        tmtx(Row,Col)=0;
    end
    %%%%%%%

      display(res)

Answer 1

[Sergey Kasyanov]

Try this. I hope I understand you right.

CostsMtx=[16,18,17,20,17;25,27,29,32,28;1.5,1.6,1.7,2,1.8;50,54,56,60,57;60,63,65,68,64];
supply=[800,600,1000,400,100];
demand=[870,435,725,464,406];
mtxsz=size(CostsMtx);
%%%%%%%%%%
tmtx=CostsMtx;
res=zeros(mtxsz);
%%%%%%%%%
R=supply;
D=demand;
%repeat infinum times
while true
  x=min(tmtx(tmtx>0));

    %if there are no any x>0 then stop repeat
    if isempty(x)
      break;
    end

    [Row,Col]=find(tmtx==x);
    rm=R(1,Row);
    dm=D(1,Col);
    if R(1,Row)==0
        tmtx(Row,Col)=0;
    end
    if D(1,Col)==0
        tmtx(Row,Col)=0;
    end
    if rm<dm
        res(Row,Col)=tmtx(Row,Col)*R(1,Row);
        D(1,Col)=D(1,Col)-R(1,Row);
        R(1,Row)=0;
        tmtx(Row,Col)=0;
    end
    if dm<rm
        res(Row,Col)=tmtx(Row,Col)*D(1,Col);
        R(1,Row)=R(1,Row)-D(1,Col);
        D(1,Col)=0;
        tmtx(Row,Col)=0;
    end
  end
    %%%%%%%