Making pascal's triangle with mpz_t's
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Published on 2010-04-29T19:51:01Z
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2010/04/29
19:57 UTC
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Hey, I'm trying to convert a function I wrote to generate an array of longs that respresents Pascal's triangles into a function that returns an array of mpz_t's. However with the following code:
mpz_t* make_triangle(int rows, int* count) {
//compute triangle size using 1 + 2 + 3 + ... n = n(n + 1) / 2
*count = (rows * (rows + 1)) / 2;
mpz_t* triangle = malloc((*count) * sizeof(mpz_t));
//fill in first two rows
mpz_t one;
mpz_init(one);
mpz_set_si(one, 1);
triangle[0] = one; triangle[1] = one; triangle[2] = one;
int nums_to_fill = 1;
int position = 3;
int last_row_pos;
int r, i;
for(r = 3; r <= rows; r++) {
//left most side
triangle[position] = one;
position++;
//inner numbers
mpz_t new_num;
mpz_init(new_num);
last_row_pos = ((r - 1) * (r - 2)) / 2;
for(i = 0; i < nums_to_fill; i++) {
mpz_add(new_num, triangle[last_row_pos + i], triangle[last_row_pos + i + 1]);
triangle[position] = new_num;
mpz_clear(new_num);
position++;
}
nums_to_fill++;
//right most side
triangle[position] = one;
position++;
}
return triangle;
}
I'm getting errors saying: incompatible types in assignment for all lines where a position in the triangle is being set (i.e.: triangle[position] = one;).
Does anyone know what I might be doing wrong?
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