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Merge 35924d415e into 210187cf77

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Christopher Wellons 2023-05-16 02:23:12 -07:00 • committed by GitHub
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3 changed files with 24 additions and 12 deletions
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14
libc/tinymath/fsum.c
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@ -24,8 +24,14 @@
*/ */
double fsum(const double *p, size_t n) { double fsum(const double *p, size_t n) {
size_t i; size_t i;
double s; double err, sum, t, y;
if (n > 8) return fsum(p, n / 2) + fsum(p + n / 2, n - n / 2);
for (s = i = 0; i < n; ++i) s += p[i]; sum = err = 0;
return s; for (i = 0; i < n; ++i) {
y = p[i] - err;
t = sum + y;
err = (t - sum) - y;
sum = t;
}
return sum;
} }

14
libc/tinymath/fsumf.c
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@ -23,9 +23,15 @@
* Adds floats in array. * Adds floats in array.
*/ */
float fsumf(const float *p, size_t n) { float fsumf(const float *p, size_t n) {
float s;
size_t i; size_t i;
if (n > 8) return fsumf(p, n / 2) + fsumf(p + n / 2, n - n / 2); double err, sum, t, y;
for (s = i = 0; i < n; ++i) s += p[i];
return s; sum = err = 0;
for (i = 0; i < n; ++i) {
y = p[i] - err;
t = sum + y;
err = (t - sum) - y;
sum = t;
}
return sum;
} }

8
test/libc/tinymath/fsum_test.c
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@ -31,21 +31,21 @@ double D[N];
void SetUp(void) { void SetUp(void) {
int i; int i;
for (i = 0; i < N / 2; ++i) { for (i = 0; i < N / 2; ++i) {
D[i * 2 + 0] = 1000000000.1; D[i * 2 + 0] = 10000000000.1;
D[i * 2 + 1] = 1.1; D[i * 2 + 1] = 1.1;
} }
for (i = 0; i < N / 2; ++i) { for (i = 0; i < N / 2; ++i) {
F[i * 2 + 0] = 1000.1; F[i * 2 + 0] = 10000.1;
F[i * 2 + 1] = 1.1; F[i * 2 + 1] = 1.1;
} }
} }
TEST(fsum, test) { TEST(fsum, test) {
EXPECT_STREQ("500000000.6", _gc(xasprintf("%.15g", fsum(D, N) / N))); EXPECT_STREQ("5000000000.6", _gc(xasprintf("%.16g", fsum(D, N) / N)));
} }
TEST(fsumf, test) { TEST(fsumf, test) {
EXPECT_STREQ("500.6", _gc(xasprintf("%.7g", fsumf(F, N) / N))); EXPECT_STREQ("5000.5996", _gc(xasprintf("%.8g", fsumf(F, N) / N)));
} }
BENCH(fsum, bench) { BENCH(fsum, bench) {