performance - Same function? runs about 10 time slower with GMP(C++) -

i wrote mandelbrot zoom in c++ zoom limited due floating point inaccuracy. that's why wrote whole thing againg gmp library.

but have problems performance. i'm new gmp maybe messed few things:

here original code:

int iterate(double xp, double yp, int iterations){ double length = 1; double x = 0; double y = 0; double r; for(int = 0; < iterations && length <= 2; i++){     double xtemp = x;     //calculate real part     x = (x*x)+xp-(y*y);     //calculate imaginary part     y = 2*xtemp*y+yp;     //calculate lenth     length = sqrt(x*x+y*y);     r = i+1; } if(length > 2)     return r; return 0; 

}

same function gmp (i think it's same), added 2 variables, temp , temp2, store values calculation shouldn't make 10 times slower:

int iterategmp(mpf_t xpgmp, mpf_t ypgmp, int iterations){ double r;  mpf_set_default_prec (20);  mpf_t length; mpf_init(length); mpf_set_d(length, 1); mpf_t x; mpf_init(x); mpf_set_d(x, 0); mpf_t y; mpf_init(y); mpf_set_d(y, 0); mpf_t xtemp; mpf_init(xtemp); mpf_t tempgmp; mpf_init(tempgmp); mpf_t temp2gmp; mpf_init(temp2gmp);   for(int = 0; < iterations && mpf_cmp_ui(length, 2)<0; i++){     mpf_set(xtemp, x);      //calculate real part     mpf_mul(tempgmp, x, x);     mpf_add(tempgmp, tempgmp, xpgmp);     mpf_mul(temp2gmp, y, y);     mpf_sub(x, tempgmp, temp2gmp);      //calculate imaginary part     mpf_mul(tempgmp, xtemp, y);     mpf_mul_ui(tempgmp, tempgmp, 2);     mpf_add(y, tempgmp, ypgmp);      //calculate length     mpf_mul(tempgmp, x, x);     mpf_mul(temp2gmp, y, y);     mpf_add(tempgmp, tempgmp, temp2gmp);     mpf_sqrt(length, tempgmp);     r = i+1; } if(mpf_cmp_ui(length, 2) > 0){     return r; } return 0; 

}

i hope can me.

i added 2 variables, temp , temp2, store values calculation shouldn't make 10 times slower

operations on float , double handled hardware. whereas operations on gmp types handled gmp library in software.

gmp values require more memory store , memory bottleneck.