47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <math.h>
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#define TIMER_CLEAR (tv1.tv_sec = tv1.tv_usec = tv2.tv_sec = tv2.tv_usec = 0)
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#define TIMER_START gettimeofday(&tv1, (struct timezone*)0)
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#define TIMER_ELAPSED (double) (tv2.tv_usec-tv1.tv_usec)/1000000.0+(tv2.tv_sec-tv1.tv_sec)
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#define TIMER_STOP gettimeofday(&tv2, (struct timezone*)0)
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struct timeval tv1,tv2;
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double func(double num)
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{
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return sqrt(1-pow(num,2));
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}
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int main(int argc, char * argv[])
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{
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TIMER_CLEAR;
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if (argc < 2)
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{
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printf("Please specify the iterations\n");
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return -1;
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}
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float iterations = atoi(argv[1]);
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// integral bounds
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float integral, sumOfRectangles;
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double a,b, area;
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a=0;
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b=1;
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double h = (b-a)/iterations;
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int i=0;
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TIMER_START;
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// sum up Trapezoids
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for (i; i <= iterations-1; i++)
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{
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area=h*func(a+(i-1)*h);
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sumOfRectangles+=area;
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}
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integral=4*sumOfRectangles;
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TIMER_STOP;
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//integral = h*((sqrt(1-pow(a,2))/2)+sumOfTrapezoids+sqrt(1-pow(a,2))/2);
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printf("Computed Sum for Rectangular Decomposition: %f\n", integral);
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printf("Time elapsed = %f seconds\n", TIMER_ELAPSED);
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}
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