I keep getting syntax error and i don't know why

Question

Here is my model.

set ch ;
set k ;
param a{i in ch , j in k};
param b{i in ch };
param c{j in k };

var x{i in ch , j in k}>= 0;

minimize cost: sum{i in ch , j in k} x[i,j]* a[i,j];

s.t. D{i in ch }: sum{j in k} x[i,j] >= b[i];
s.t. E{j in k }: sum{i in ch } x[i,j] <= c[j];

data;

set ch := ch1 ch2 ch3;
set k := k1 k2;

param a : ch1 ch2 ch3 :=
k1 100 180 100
k2 50 120 80;
param b := ch1 50
ch2 80
ch3 100;
param c := k1 400
k2 90;

solve;

display x{i in ch , j in k};

end;

I got the following error when solving the model:

cau5.mod:25: syntax error in data section

This is really confusing because there is a model that have the same format but solving just fine. Please someone help.

Answer 1

The problem is that you have row and column keys swapped in the data table for a. You can add (tr) which means "transpose" to fix this:

param a (tr) : ch1 ch2 ch3 :=
k1 100 180 100
k2 50 120 80;