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| author | MITSUNARI Shigeo <herumi@nifty.com> | 2019-02-20 09:29:47 +0800 |
|---|---|---|
| committer | MITSUNARI Shigeo <herumi@nifty.com> | 2019-02-20 09:29:47 +0800 |
| commit | b401313c71119e48f9e2edd4484c416b7ca349cc (patch) | |
| tree | d62144c6a23d5e423b7d0daa3f77247ca7e66d54 | |
| parent | 08148dcf605117f495545cdf3ce29afb1e9c963e (diff) | |
| download | tangerine-mcl-b401313c71119e48f9e2edd4484c416b7ca349cc.tar.gz tangerine-mcl-b401313c71119e48f9e2edd4484c416b7ca349cc.tar.zst tangerine-mcl-b401313c71119e48f9e2edd4484c416b7ca349cc.zip | |
evaluatePolynomial sets out = c[0] if cSize = 1
| -rw-r--r-- | include/mcl/lagrange.hpp | 9 | ||||
| -rw-r--r-- | test/bench.hpp | 2 |
2 files changed, 9 insertions, 2 deletions
diff --git a/include/mcl/lagrange.hpp b/include/mcl/lagrange.hpp index feca80d..18e0597 100644 --- a/include/mcl/lagrange.hpp +++ b/include/mcl/lagrange.hpp @@ -63,15 +63,20 @@ void LagrangeInterpolation(bool *pb, G& out, const F *S, const G *vec, size_t k) /* out = f(x) = c[0] + c[1] * x + c[2] * x^2 + ... + c[cSize - 1] * x^(cSize - 1) - @retval 0 if succeed else -1 + @retval 0 if succeed else -1 (if cSize == 0) */ template<class G, class T> void evaluatePolynomial(bool *pb, G& out, const G *c, size_t cSize, const T& x) { - if (cSize < 2) { + if (cSize == 0) { *pb = false; return; } + if (cSize == 1) { + out = c[0]; + *pb = true; + return; + } G y = c[cSize - 1]; for (int i = (int)cSize - 2; i >= 0; i--) { G::mul(y, y, x); diff --git a/test/bench.hpp b/test/bench.hpp index 12868d3..cc1639e 100644 --- a/test/bench.hpp +++ b/test/bench.hpp @@ -187,4 +187,6 @@ void testLagrange() CYBOZU_TEST_EQUAL(s, c[0]); mcl::LagrangeInterpolation(s, x, y, 1); CYBOZU_TEST_EQUAL(s, y[0]); + mcl::evaluatePolynomial(y[0], c, 1, x[0]); + CYBOZU_TEST_EQUAL(y[0], c[0]); } |