Touring Additional Utility APIs - Beginning Java 7 - page 566

b.setValue(0, 0, 4); // | 4 7 |
b.setValue(1, 0, 5); // | 5 8 |
b.setValue(2, 0, 6); // | 6 9 |
b.setValue(0, 1, 7);
b.setValue(1, 1, 8);
b.setValue(2, 1, 9);
dump(b);
dump(multiply(a, b));

}
static void dump(Matrix m)
{

for (int i = 0; i < m.getRows(); i++)
{

for (int j = 0; j < m.getCols(); j++)
System.out.print(m.getValue(i, j)+" ");
System.out.println();

}
System.out.println();

}
static Matrix multiply(Matrix a, Matrix b)
{

if (a.getCols() != b.getRows())
throw new IllegalArgumentException("rows/columns
mismatch");
Matrix result = new Matrix(a.getRows(), b.getCols());
for (int i = 0; i < a.getRows(); i++)
for (int j = 0; j < b.getCols(); j++)
for (int k = 0; k < a.getCols(); k++)
result.setValue(i, j, result.getValue(i,

j)+a.getValue(i, k)*

b.getValue(k, j));

return result;

}

}

Listing 6-8 ' s MatMult class declares a multiply() method that demonstrates
matrixmultiplication. Afterverifyingthatthenumberofcolumnsinthefirst Matrix