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simplify anti-aliasing assertion

This commit is contained in:
Jack Wrenn 2019-04-15 17:54:10 -04:00 committed by Sébastien Crozet
parent 306f096c64
commit 05eb9ac2ba
1 changed files with 5 additions and 17 deletions
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22
src/base/construction_slice.rs
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@ -114,26 +114,14 @@ impl<'a, N: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
let rstride = rstride.value(); let rstride = rstride.value();
let cstride = cstride.value(); let cstride = cstride.value();
// `Storage::linear_index`
let index = |i, j| (i * rstride) + (j * cstride);
// The final condition of each arm is an expression in the form:
// index(i₀, j₀) != index(i₁, j₁)
// If this expression is `false`, then the values (i₀, j₀)
// and (i₁, j₁) are concrete examples of indices that would
// collide if the matrix was actually constructed.
nrows * ncols <= 1 || nrows * ncols <= 1 ||
match (rstride, cstride) { match (rstride, cstride) {
(0, 0) => index(0, 0) != index(nrows - 1, ncols - 1), (0, 0) => false, // otherwise: matrix[(0, 0)] == index[(nrows - 1, ncols - 1)],
(0, _) => nrows <= 1 || index(0, 0) != index(nrows - 1, 0), (0, _) => nrows <= 1, // otherwise: matrix[(0, 0)] == index[(nrows - 1, 0)],
(_, 0) => ncols <= 1 || index(0, 0) != index(0, ncols - 1), (_, 0) => ncols <= 1, // otherwise: matrix[(0, 0)] == index[(0, ncols - 1)],
(_, _) => { (_, _) => { // otherwise: matrix[(0, numer)] == index[(denom, 0)]
let ratio = Ratio::new(rstride, cstride); let ratio = Ratio::new(rstride, cstride);
let numer = *ratio.numer(); nrows <= *ratio.denom() || ncols <= *ratio.numer()
let denom = *ratio.denom();
nrows <= denom || ncols <= numer
|| index(0, numer) != index(denom, 0)
} }
} }
}, },