refactor c files
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2
posts/stereo/1/.gitignore
vendored
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2
posts/stereo/1/.gitignore
vendored
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@ -0,0 +1,2 @@
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compare_complex
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compare_math
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10
posts/stereo/1/Makefile
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10
posts/stereo/1/Makefile
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@ -0,0 +1,10 @@
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default: compare_complex compare_math
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clean:
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rm -rf compare_complex compare_math
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compare_complex:
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gcc main.c stereo_complex.c -lm -DUSE_COMPLEX -o compare_complex
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compare_math:
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gcc main.c stereo_math.c -lm -o compare_math
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168
posts/stereo/1/main.c
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168
posts/stereo/1/main.c
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@ -0,0 +1,168 @@
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#include <complex.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#define STR_RED "\x1b[31m"
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#define STR_GREEN "\x1b[32m"
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#define STR_NORM "\x1b[m"
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#define SECONDS_PER_NANOSECOND 1000000000
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#define NUM_LOOPS 100000
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#define SQRT_NUM_LOOPS 100
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struct circle {
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double c;
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double s;
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};
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void turn_update(double turn, void* result);
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void approx_turn_update(double turn, void* result);
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#ifdef USE_COMPLEX
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#define EXTRACT_REAL(a) creal(a)
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#define EXTRACT_IMAG(a) cimag(a)
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#define CIRCLE_TYPE double complex
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#else
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#define EXTRACT_REAL(a) (a.c)
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#define EXTRACT_IMAG(a) (a.s)
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#define CIRCLE_TYPE struct circle
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#endif
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void print_errors(
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const double* inputs,
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const CIRCLE_TYPE* ideals,
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const CIRCLE_TYPE* approxs,
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int n
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)
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{
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double c_error, s_error;
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double largest_c_error, largest_s_error;
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size_t largest_c_index, largest_s_index;
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double total_c_error = 0, total_s_error = 0;
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size_t i;
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CIRCLE_TYPE ideal, approx;
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for (i = 0; i < n; i++) {
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ideal = ideals[i];
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approx = approxs[i];
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// squared error in c components
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c_error = EXTRACT_REAL(ideal) - EXTRACT_REAL(approx);
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c_error *= c_error;
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// squared error in s components
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s_error = EXTRACT_IMAG(ideal) - EXTRACT_IMAG(approx);
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s_error *= s_error;
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if (largest_c_error < c_error) {
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largest_c_error = c_error;
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largest_c_index = i;
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}
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if (largest_s_error < s_error) {
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largest_s_error = s_error;
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largest_s_index = i;
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}
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total_c_error += c_error;
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total_s_error += s_error;
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}
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// these now contain the *average* squared error
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total_c_error /= (double)n;
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total_s_error /= (double)n;
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printf(
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"Squared error in cosines: \n"
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"\tAverage: %f (%f%% error)\n"
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"\tLargest: %f (%f%% error)\n"
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"\t\tInput:\t\t%f\n"
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"\t\tValue:\t\t%f\n"
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"\t\tApproximation:\t%f\n",
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total_c_error, sqrt(total_c_error) * SQRT_NUM_LOOPS, largest_c_error,
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sqrt(largest_c_error) * SQRT_NUM_LOOPS, inputs[largest_c_index],
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EXTRACT_REAL(ideals[largest_c_index]),
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EXTRACT_REAL(approxs[largest_c_index])
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);
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printf(
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"Squared error in sines: \n"
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"\tAverage: %f (%f%% error)\n"
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"\tLargest: %f (%f%% error)\n"
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"\t\tInput:\t\t%f\n"
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"\t\tValue:\t\t%f\n"
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"\t\tApproximation:\t%f\n",
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total_s_error, sqrt(total_s_error) * SQRT_NUM_LOOPS, largest_s_error,
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sqrt(largest_s_error) * SQRT_NUM_LOOPS, inputs[largest_c_index],
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EXTRACT_IMAG(ideals[largest_s_index]),
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EXTRACT_IMAG(approxs[largest_s_index])
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);
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}
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// time the length of the computation `f` in nanoseconds
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long time_computation(
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void (*f)(double, void*), const double* inputs, CIRCLE_TYPE* results, int n
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)
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{
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size_t i;
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struct timespec tp1;
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struct timespec tp2;
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clock_gettime(CLOCK_MONOTONIC, &tp1);
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for (i = 0; i < n; i++) {
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f(inputs[i], results + i);
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}
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clock_gettime(CLOCK_MONOTONIC, &tp2);
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return SECONDS_PER_NANOSECOND * (tp2.tv_sec - tp1.tv_sec) +
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(tp2.tv_nsec - tp1.tv_sec);
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}
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int main(int argn, char** args)
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{
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long trig_time, rat_time;
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double rands[NUM_LOOPS];
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CIRCLE_TYPE trigs[NUM_LOOPS];
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CIRCLE_TYPE rats[NUM_LOOPS];
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size_t i;
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for (i = 0; i < NUM_LOOPS; i++) {
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rands[i] = rand() / (double)RAND_MAX;
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}
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trig_time = time_computation(&turn_update, rands, trigs, NUM_LOOPS);
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printf(
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#ifdef USE_COMPLEX
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"Timing for %d complex.h cexp:\t%ldns\n",
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#else
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"Timing for %d math.h sin and cos:\t%ldns\n",
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#endif
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NUM_LOOPS,
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trig_time
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);
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rat_time = time_computation(&approx_turn_update, rands, rats, NUM_LOOPS);
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printf("Timing for %d approximations:\t%ldns\n", NUM_LOOPS, rat_time);
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long diff = rat_time - trig_time;
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double frac_speed;
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if (diff > 0) {
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frac_speed = rat_time / (double)trig_time;
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printf(
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STR_RED "stdlib" STR_NORM " faster, speedup: %ldns (%2.2fx)\n",
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diff, frac_speed
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);
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} else {
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frac_speed = trig_time / (double)rat_time;
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printf(
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STR_GREEN "Approximation" STR_NORM
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" faster, speedup: %ldns (%2.2fx)\n",
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-diff, frac_speed
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);
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print_errors(rands, trigs, rats, NUM_LOOPS);
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}
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return 0;
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}
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@ -1,20 +1,7 @@
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#include <complex.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#define STRRED "\x1b[31m"
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#define STRGREEN "\x1b[32m"
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#define STRNORM "\x1b[m"
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#define SECONDS_PER_NANOSECOND 1000000000
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#define NUM_LOOPS 100000
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double complex complex_turn(double turn) { return cexp(I * M_PI * turn); }
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double complex approx_turn(double turn)
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double complex complex_approx_turn(double turn)
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{
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const static double a = 8 * M_SQRT2 / 3 - 3;
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const static double b = 4 - 8 * M_SQRT2 / 3;
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@ -27,130 +14,14 @@ double complex approx_turn(double turn)
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return (c * c - s * s) + I * (2 * c * s);
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}
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void print_errors(
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const double* inputs,
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const double complex* ideals,
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const double complex* approxs,
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int n
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)
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double complex complex_turn(double turn) { return cexp(I * M_PI * turn); }
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void turn_update(double turn, double complex* result)
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{
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double c_error, s_error;
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double largest_c_error, largest_s_error;
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size_t largest_c_index, largest_s_index;
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double total_c_error = 0, total_s_error = 0;
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size_t i;
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double complex ideal, approx;
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for (i = 0; i < n; i++) {
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ideal = ideals[i];
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approx = approxs[i];
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// squared error in c components
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c_error = creal(ideal) - creal(approx);
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c_error *= c_error;
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// squared error in s components
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s_error = cimag(ideal) - cimag(approx);
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s_error *= s_error;
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if (largest_c_error < c_error) {
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largest_c_error = c_error;
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largest_c_index = i;
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}
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if (largest_s_error < s_error) {
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largest_s_error = s_error;
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largest_s_index = i;
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}
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total_c_error += c_error;
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total_s_error += s_error;
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}
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// these now contain the *average* squared error
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total_c_error /= (double)n;
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total_s_error /= (double)n;
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printf(
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"Squared error in cosines: \n"
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"\tAverage: %f (%f%% error)\n"
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"\tLargest: %f (%f%% error)"
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"\n\t\tInput:\t\t%f\n\t\tValue:\t\t%f\n\t\tApproximation:\t%f\n",
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total_c_error, sqrt(total_c_error) * 100, largest_c_error,
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sqrt(largest_c_error) * 100, inputs[largest_c_index],
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creal(ideals[largest_c_index]), creal(approxs[largest_c_index])
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);
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printf(
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"Squared error in sines: \n"
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"\tAverage: %f (%f%% error)\n\tLargest: %f (%f%% error)"
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"\n\t\tInput:\t\t%f\n\t\tValue:\t\t%f\n\t\tApproximation:\t%f\n",
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total_s_error, sqrt(total_s_error) * 100, largest_s_error,
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sqrt(largest_s_error) * 100, inputs[largest_c_index],
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cimag(ideals[largest_s_index]), cimag(approxs[largest_s_index])
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);
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*result = complex_turn(turn);
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}
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// time the length of the computation `f` in nanoseconds
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long time_computation(
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double complex (*f)(double),
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const double* inputs,
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double complex* results,
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int n
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)
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void approx_turn_update(double turn, double complex* result)
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{
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size_t i;
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long tick_s;
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long tick_ns;
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struct timespec tp;
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clock_gettime(CLOCK_MONOTONIC, &tp);
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tick_ns = tp.tv_nsec;
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tick_s = tp.tv_sec;
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for (i = 0; i < n; i++) {
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results[i] = f(inputs[i]);
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}
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clock_gettime(CLOCK_MONOTONIC, &tp);
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return SECONDS_PER_NANOSECOND * (tp.tv_sec - tick_s) +
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(tp.tv_nsec - tick_ns);
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}
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int main(int argn, char** args)
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{
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long trig_time, rat_time;
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double rands[NUM_LOOPS];
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double complex trigs[NUM_LOOPS];
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double complex rats[NUM_LOOPS];
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size_t i;
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for (i = 0; i < NUM_LOOPS; i++) {
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rands[i] = rand() / (double)RAND_MAX;
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}
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trig_time = time_computation(&complex_turn, rands, trigs, NUM_LOOPS);
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printf("Timing for %d math.h sin and cos:\t%ldns\n", NUM_LOOPS, trig_time);
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rat_time = time_computation(&approx_turn, rands, rats, NUM_LOOPS);
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printf("Timing for %d approximations:\t%ldns\n", NUM_LOOPS, rat_time);
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long diff = rat_time - trig_time;
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double frac_speed;
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if (diff > 0) {
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frac_speed = rat_time / (double)trig_time;
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printf(
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STRRED "math.h" STRNORM " faster, speedup: %ldns (%2.2fx)\n", diff,
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frac_speed
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);
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} else {
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frac_speed = trig_time / (double)rat_time;
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printf(
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STRGREEN "Approximation" STRNORM
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" faster, speedup: %ldns (%2.2fx)\n",
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-diff, frac_speed
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);
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print_errors(rands, trigs, rats, NUM_LOOPS);
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}
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return 0;
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*result = complex_approx_turn(turn);
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}
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@ -1,29 +1,15 @@
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#define STRRED "\x1b[31m"
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#define STRGREEN "\x1b[32m"
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#define STRNORM "\x1b[m"
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struct circle {
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double c;
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double s;
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};
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double a = 8 * M_SQRT2 / 3 - 3;
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double b = 4 - 8 * M_SQRT2 / 3;
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void trig(double turn, struct circle* ret)
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void approx_turn_update(double turn, struct circle* ret)
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{
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double arg = M_PI * turn;
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ret->c = cos(arg);
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ret->s = sin(arg);
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}
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static const double a = 8 * M_SQRT2 / 3 - 3;
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static const double b = 4 - 8 * M_SQRT2 / 3;
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void rational(double turn, struct circle* ret)
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{
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double p = turn * (b * turn * turn + a);
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double q = p * p;
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double r = 1 + q;
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@ -33,108 +19,9 @@ void rational(double turn, struct circle* ret)
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ret->s = 2 * c * s;
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}
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double
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errors(int n, const struct circle* circles1, const struct circle* circles2)
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void turn_update(double turn, struct circle* ret)
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{
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double c_error, s_error;
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double largest_c_error, largest_s_error;
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double total_c_error = 0, total_s_error = 0;
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int i;
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struct circle circle1, circle2;
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for (i = 0; i < n; i++) {
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circle1 = circles1[i];
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circle2 = circles2[i];
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// squared error in c components
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c_error = circle1.c - circle2.c;
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c_error *= c_error;
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// squared error in s components
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s_error = circle1.s - circle2.s;
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s_error *= s_error;
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if (largest_c_error < c_error)
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largest_c_error = c_error;
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if (largest_s_error < s_error)
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largest_s_error = s_error;
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total_c_error += c_error;
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total_s_error += s_error;
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}
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// these now contain the *average* squared error
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total_c_error /= (double)n;
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total_s_error /= (double)n;
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printf(
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"Squared error in cosines: \n\tAverage: %f (%f%% error)\n\tLargest: %f "
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"(%f%% error)\n",
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total_c_error, sqrt(total_c_error) * 100, largest_c_error,
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sqrt(largest_c_error) * 100
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);
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printf(
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"Squared error in sines: \n\tAverage: %f (%f%% error)\n\tLargest: %f "
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"(%f%% error)\n",
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total_s_error, sqrt(total_s_error) * 100, largest_s_error,
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sqrt(largest_s_error) * 100
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);
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return 0;
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}
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int main(int argn, char** args)
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{
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// struct circle ret;
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int i;
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struct timespec tp;
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long tick;
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long trig_time, rat_time;
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double rands[10000];
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struct circle trigs[10000];
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struct circle rats[10000];
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for (i = 0; i < 10000; i++) {
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rands[i] = rand() / (double)RAND_MAX;
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}
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clock_gettime(CLOCK_MONOTONIC, &tp);
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tick = tp.tv_nsec;
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for (i = 0; i < 10000; i++) {
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trig(rands[i], trigs + i);
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}
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clock_gettime(CLOCK_MONOTONIC, &tp);
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// this isn't quite proper, since the clock may have ticked over a second
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trig_time = tp.tv_nsec - tick;
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printf("Timing for 10000 math.h sin and cos:\t%ldns\n", trig_time);
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clock_gettime(CLOCK_MONOTONIC, &tp);
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tick = tp.tv_nsec;
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for (i = 0; i < 10000; i++) {
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rational(rands[i], rats + i);
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}
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clock_gettime(CLOCK_MONOTONIC, &tp);
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rat_time = tp.tv_nsec - tick;
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printf("Timing for 10000 approximations:\t%ldns\n", rat_time);
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double fracSpeed;
|
||||
long linSpeed = rat_time - trig_time;
|
||||
if (linSpeed > 0) {
|
||||
fracSpeed = rat_time / (double)trig_time;
|
||||
printf(
|
||||
STRRED "math.h" STRNORM " faster, speedup: %ldns (%2.2fx)\n",
|
||||
linSpeed, fracSpeed
|
||||
);
|
||||
} else {
|
||||
fracSpeed = trig_time / (double)rat_time;
|
||||
printf(
|
||||
STRGREEN "Approximation" STRNORM
|
||||
" faster, speedup: %ldns (%2.2fx)\n",
|
||||
-linSpeed, fracSpeed
|
||||
);
|
||||
errors(10000, rats, trigs);
|
||||
}
|
||||
double arg = M_PI * turn;
|
||||
ret->c = cos(arg);
|
||||
ret->s = sin(arg);
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user