41 lines
797 B
C
41 lines
797 B
C
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#include <stdlib.h>
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#include <stdio.h>
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/* lower and upper iteration limits centered around 1.0 */
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static double const eps1m01 = 1.0 - 0x1P-01;
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static double const eps1p01 = 1.0 + 0x1P-01;
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static double const eps1m24 = 1.0 - 0x1P-24;
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static double const eps1p24 = 1.0 + 0x1P-24;
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int main(int argc, char* argv[argc+1]) {
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for (int i = 1; i < argc; ++i) {
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double const a = strtod(argv[i], 0);
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double x = 1.0;
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for (;;) {
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double prod = a*x;
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if (prod < eps1m01) {
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x *= 2.0;
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} else if (eps1p01 < prod) {
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x *= 0.5;
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} else {
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break;
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}
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}
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for (;;) {
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double prod = a*x;
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if ((prod < eps1m24) || (eps1p24 < prod)) {
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x *= (2.0 - prod);
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} else {
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break;
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}
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}
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printf("heron: a=%.5e,\tx=%.5e,\ta*x=%.12f\n",
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a, x, a*x);
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}
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return EXIT_SUCCESS;
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}
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