<![CDATA[
int main() {
int m = m, n = 4;
array double a[4][4] = {1, 5, -7, 4,
3, 2, 5, 2,
3, 2, 5, 2,
3, 9, 5, 2}; /* a[m][n] */
array double q[n][n];
array double r[n][n];
qrdecomp(a, q, r);
printf("q = \n%f\n", q);
printf("r = \n%f\n", r);
printf("q*r = \n%f\n", q*r);
m = 2;
n = 4;
array double a1[2][4] = {1, 5, -7, 4,
3, 2, 5, 2}; /* a[m][n] */
array double q1[m][m]; // m<n
array double r1[m][n];
qrdecomp(a1, q1, r1);
printf("q1^T*q1 = \n%f\n", transpose(q1)*q1);
printf("q1 = \n%f\n", q1);
printf("r1 = \n%f\n", r1);
printf("q1*r1 = \n%f\n", q1*r1);
array double a2[4][2] = {1, 5,
-7, 4,
3, 2,
5, 2}; /* a[m][n] */
m = 4;
n = 2;
array double q2[m][n], q21[m][m]; // m>=n
array double r2[n][n], r21[m][n];
int status;
status = qrdecomp(a2, q21, r21);
if(status == 0) {
printf("q21^T*q21 = \n%f\n", transpose(q21)*q21);
printf("q21 = \n%f\n", q21);
printf("r21 = \n%f\n", r21);
printf("q21*r21 = \n%f\n", q21*r21);
}
else
printf("error: numerical error in qrdecomp()\n");
status = qrdecomp(a2, q2, r2);
if(status == 0) {
printf("q2^T*q2 = \n%f\n", transpose(q2)*q2);
printf("q2 = \n%f\n", q2);
printf("r2 = \n%f\n", r2);
printf("q2*r2 = \n%f\n", q2*r2);
}
else
printf("error: numerical error in qrdecomp()\n");
}
]]>
<![CDATA[
q =
-0.188982 0.511914 0.837991 0.000000
-0.566947 -0.405266 0.119713 0.707107
-0.566947 -0.405266 0.119713 -0.707107
-0.566947 0.639893 -0.518756 -0.000000
r =
-5.291503 -8.315218 -7.181325 -4.157609
0.000000 6.697548 -4.436592 1.706382
0.000000 0.000000 -7.262591 2.793304
0.000000 0.000000 0.000000 0.000000
q*r =
1.000000 5.000000 -7.000000 4.000000
3.000000 2.000000 5.000000 2.000000
3.000000 2.000000 5.000000 2.000000
3.000000 9.000000 5.000000 2.000000
q1^T*q1 =
1.000000 0.000000
0.000000 1.000000
q1 =
-0.316228 -0.948683
-0.948683 0.316228
r1 =
-3.162278 -3.478505 -2.529822 -3.162278
0.000000 -4.110961 8.221922 -3.162278
q1*r1 =
1.000000 5.000000 -7.000000 4.000000
3.000000 2.000000 5.000000 2.000000
q21^T*q21 =
1.000000 0.000000 0.000000 0.000000
0.000000 1.000000 0.000000 0.000000
0.000000 0.000000 1.000000 0.000000
0.000000 0.000000 0.000000 1.000000
q21 =
-0.109109 -0.730552 -0.408074 -0.536530
0.763763 -0.491027 0.173257 0.381499
-0.327327 -0.323359 0.873744 -0.157694
-0.545545 -0.347312 -0.200072 0.736021
r21 =
-9.165151 0.763763
0.000000 -6.958209
0.000000 0.000000
0.000000 0.000000
q21*r21 =
1.000000 5.000000
-7.000000 4.000000
3.000000 2.000000
5.000000 2.000000
q2^T*q2 =
1.000000 0.000000
0.000000 1.000000
q2 =
-0.109109 -0.730552
0.763763 -0.491027
-0.327327 -0.323359
-0.545545 -0.347312
r2 =
-9.165151 0.763763
0.000000 -6.958209
q2*r2 =
1.000000 5.000000
-7.000000 4.000000
3.000000 2.000000
5.000000 2.000000
]]>