dm1sh/polynomial_interpolation
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

idk, when i wrote it, but it somehow works

Browse Source
This commit is contained in:
Dmitriy Shishkov 2022-05-24 23:27:04 +03:00
parent f26825e77b
commit 75dce20390
No known key found for this signature in database
GPG Key ID: 26720CB2A9608C97
2 changed files with 90 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

120
main.c
View File

@ -27,9 +27,9 @@ arr *init(int n)
a->size = n;
a->p = (float *)malloc(sizeof(float) * n);
a->p = (double *)malloc(sizeof(double) * n);
for (int i = 0; i < n; i++)
insert(a, i, 0);
set(a, i, 0);
return a;
}
@ -39,9 +39,9 @@ arr *resize(arr *a, int new_size)
if (a->size == new_size)
return a;
float *new_p = (float *)malloc(sizeof(float) * new_size);
double *new_p = (double *)malloc(sizeof(double) * new_size);
for (int i = 0; i < min(new_size, a->size); i++)
new_p[i] = a->p[i];
new_p[i] = get(a, i);
free(a->p);
@ -54,35 +54,60 @@ arr *resize(arr *a, int new_size)
return a;
}
void insert(arr *a, int pos, float val)
int convert_addr(arr *a, int pos)
{
pos = pos % a->size;
if (pos < 0)
pos = a->size + pos;
return pos;
}
double get(arr *a, int pos)
{
pos = convert_addr(a, pos);
return a->p[pos];
}
void set(arr *a, int pos, double val)
{
pos = convert_addr(a, pos);
a->p[pos] = val;
// printa(a, 1);
}
arr *add(arr *a, arr *b)
{
for (int i = 0; i < a->size; i++)
insert(a, i, a->p[i] + b->p[i]);
set(a, i, a->p[i] + b->p[i]);
return a;
}
arr *mult(arr *a, float mul)
arr *mult(arr *a, double mul)
{
arr *res = init(a->size);
for (int i = 0; i < a->size; i++)
insert(res, i, a->p[i] * mul);
set(res, i, a->p[i] * mul);
return res;
}
void printa(arr *a)
void printa(arr *a, int q)
{
if (q)
{
for (int i = 0; i < a->size; i++)
printf("%f ", get(a, i));
printf("\n");
return;
}
printf("Array of size %d:\n", a->size);
for (int i = 0; i < a->size; i++)
@ -90,7 +115,7 @@ void printa(arr *a)
printf("\n");
for (int i = 0; i < a->size; i++)
printf("%5.2f ", a->p[i]);
printf("%5.2f ", get(a, i));
printf("\n");
}
@ -101,7 +126,7 @@ arr *arr_without_el(arr *a, int ex_pos)
{
if (i == ex_pos)
continue;
insert(res, pos, a->p[i]);
set(res, pos, a->p[i]);
pos++;
}
@ -112,7 +137,7 @@ arr *reverse(arr *a)
{
arr *res = init(a->size);
for (int i = 0; i < a->size; i++)
insert(res, i, a->p[a->size - 1 - i]);
set(res, i, a->p[a->size - 1 - i]);
return res;
}
@ -159,9 +184,9 @@ int has_comb(int *arr, int n, int k)
int mult_by_index(arr *a, int *coords, int n)
{
float res = 1;
double res = 1;
for (int i = 0; i < n; i++)
res = res * a->p[coords[i]];
res = res * get(a, coords[i]);
return res;
}
@ -176,7 +201,7 @@ int sum_of_mult_of_n_combinations(arr *a, int n)
return a->p[0];
}
float acc = 0;
double acc = 0;
int coords[n];
for (int i = 0; i < n; i++)
@ -191,13 +216,13 @@ int sum_of_mult_of_n_combinations(arr *a, int n)
int compose_denominator(arr *a, int pos)
{
float res = 1;
double res = 1;
for (int i = 0; i < a->size; i++)
{
if (i == pos)
continue;
res = res * (a->p[pos] - a->p[i]);
res = res * (get(a, pos) - get(a, i));
}
return res;
}
@ -209,17 +234,17 @@ arr *compose_interpolation_polynomial(arr *xes, arr *ys)
arr *jcoef = init(xes->size);
for (int j = 0; j < xes->size; j++)
{
int minus = !(xes->size % 2);
float denominator = compose_denominator(xes, j);
float multiplicator = ys->p[j];
int minus = (!(xes->size % 2) ? -1 : 1);
double denominator = compose_denominator(xes, j);
double multiplicator = get(ys, j);
arr *xis = arr_without_el(xes, j);
for (int i = 0; i < xes->size; i++)
{
float k_sum = sum_of_mult_of_n_combinations(xis, xes->size - 1 - i);
insert(jcoef, i, (minus ? -1 : 1) * (multiplicator * k_sum) / denominator);
minus = !minus;
double k_sum = sum_of_mult_of_n_combinations(xis, xes->size - 1 - i);
set(jcoef, i, minus * (multiplicator * k_sum) / denominator);
minus = -minus;
}
res = add(res, jcoef);
@ -232,35 +257,58 @@ arr *compose_interpolation_polynomial(arr *xes, arr *ys)
return res;
}
int main()
int main(int argc, char *argv[])
{
printf("Insert number of dots: ");
int n = 0;
int quiet_mode = 0;
if (argc > 1 && argv[1][0] == '-' && argv[1][1] == 'q')
quiet_mode = 1;
if (!quiet_mode)
printf("Insert number of dots: ");
int n = 6;
scanf("%d", &n);
printf("Insert dots coordinates in the following format:\n<x> (space) <y>\nEach dot on new line\n");
if (!quiet_mode)
printf("Insert dots coordinates in the following format:\n<x> (space) <y>\nEach dot on new line\n");
arr *xes = init(n);
arr *ys = init(n);
// set(xes, 0, 1);
// set(ys, 0, 1);
// set(xes, 1, 2);
// set(ys, 1, 2);
// set(xes, 2, 3);
// set(ys, 2, 3);
// set(xes, 3, 4);
// set(ys, 3, 4);
// set(xes, 4, 5);
// set(ys, 4, 5);
// set(xes, 5, 6);
// set(ys, 5, 6);
for (int i = 0; i < n; i++)
{
float x, y;
scanf("%f %f", &x, &y);
double x, y;
scanf("%lf %lf", &x, &y);
insert(xes, i, x);
insert(ys, i, y);
set(xes, i, x);
set(ys, i, y);
}
printf("Inserted the following doths:\n");
printa(xes);
printa(ys);
if (!quiet_mode)
{
printf("Inserted the following doths:\n");
printa(xes, 0);
printa(ys, 0);
}
arr *res = compose_interpolation_polynomial(xes, ys);
printf("Resulting polynomial will have such coeficients:\n");
if (!quiet_mode)
printf("Resulting polynomial will have such coeficients:\n");
arr *reversed = reverse(res);
printa(reversed);
printa(reversed, quiet_mode);
free_arr(reversed);
free_arr(res);

10
polynominal_interpolation.h
View File

@ -15,15 +15,17 @@ int max(int a, int b);
typedef struct
{
int size;
float *p;
double *p;
} arr;
arr *init(int n);
arr *resize(arr *a, int new_size);
void insert(arr *a, int pos, float val);
int convert_addr(arr *a, int pos);
double get(arr *a, int pos);
void set(arr *a, int pos, double val);
arr *add(arr *a, arr *b);
arr *mult(arr *a, float mul);
void printa(arr *a);
arr *mult(arr *a, double mul);
void printa(arr *a, int q);
arr *arr_without_el(arr *a, int ex_pos);
arr *reverse(arr *a);