tasks a-s

Task/Numeric-error-propagation/C/numeric-error-propagation.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <math.h>
+
+struct imprecise {
+    double value;
+    double delta;
+};
+
+#define SQR(x) ((x) * (x))
+struct imprecise imprecise_add(struct imprecise a, struct imprecise b)
+{
+    struct imprecise ret;
+    ret.value = a.value + b.value;
+    ret.delta = sqrt(SQR(a.delta) + SQR(b.delta));
+    return ret;
+}
+
+struct imprecise imprecise_mul(struct imprecise a, struct imprecise b)
+{
+    struct imprecise ret;
+    ret.value = a.value * b.value;
+    ret.delta = sqrt(SQR(a.value * b.delta) + SQR(b.value * a.delta));
+    return ret;
+}
+
+struct imprecise imprecise_div(struct imprecise a, struct imprecise b)
+{
+    struct imprecise ret;
+    ret.value = a.value / b.value;
+    ret.delta = sqrt(SQR(a.value * b.delta) + SQR(b.value * a.delta)) / SQR(b.value);
+    return ret;
+}
+
+struct imprecise imprecise_pow(struct imprecise a, double c)
+{
+    struct imprecise ret;
+    ret.value = pow(a.value, c);
+    ret.delta = fabs(ret.value * c * a.delta / a.value);
+    return ret;
+}
+
+int main(void) {
+    struct imprecise x1 = {100, 1.1};
+    struct imprecise y1 = {50, 1.2};
+    struct imprecise x2 = {-200, 2.2};
+    struct imprecise y2 = {-100, 2.3};
+    struct imprecise d;
+
+    d = imprecise_pow(imprecise_add(imprecise_pow(imprecise_add(x1, x2), 2),imprecise_pow(imprecise_add(y1, y2), 2)), 0.5);
+    printf("d = %f \\pm %f\n", d.value, d.delta);
+    return 0;
+}