errors less when the first coefficient is "1"

2020-04-09 09:44:05 -04:00 · 2020-04-09 09:44:05 -04:00 · e485ad5c70
parent 44f207cd52
commit e485ad5c70
1 changed files with 9 additions and 0 deletions
--- a/numerical_methods/durand_kerner_roots.c
+++ b/numerical_methods/durand_kerner_roots.c
@ -101,6 +101,15 @@ int main(int argc, char **argv)
        else if (coeffs[n] != 0)
            printf("(%g) x^%d = 0\n", coeffs[n], degree - n - 1);

+        double tmp;
+        if (n > 0)
+            coeffs[n] /= tmp; /* numerical errors less when the first coefficient is "1" */
+        else
+        {
+            tmp = coeffs[0];
+            coeffs[0] = 1;
+        }
+
        /* initialize root approximations with random values */
        if (n < degree - 1)
        {