def __init__(self, input):
assert input.type() == hl.UInt(8)
self.lut = hl.Func("lut")
self.padded = hl.Func("padded")
self.padded16 = hl.Func("padded16")
self.sharpen = hl.Func("sharpen")
self.curved = hl.Func("curved")
self.input = input
# For this lesson, we'll use a two-stage pipeline that sharpens
# and then applies a look-up-table (LUT).
# First we'll define the LUT. It will be a gamma curve.
gamma = hl.f32(1.2)
self.lut[i] = hl.u8(hl.clamp(hl.pow(i / 255.0, gamma) * 255.0, 0, 255))
# Augment the input with a boundary condition.
self.padded[x, y, c] = input[hl.clamp(x, 0,
input.width() - 1),
hl.clamp(y, 0,
input.height() - 1), c]
# Cast it to 16-bit to do the math.
self.padded16[x, y, c] = hl.u16(self.padded[x, y, c])
# Next we sharpen it with a five-tap filter.
self.sharpen[x, y, c] = (
self.padded16[x, y, c] * 2 -
(self.padded16[x - 1, y, c] + self.padded16[x, y - 1, c] +
self.padded16[x + 1, y, c] + self.padded16[x, y + 1, c]) / 4)
# Then apply the LUT.
self.curved[x, y, c] = self.lut[self.sharpen[x, y, c]]
def test_runtime_error():
x = hl.Var('x')
f = hl.Func('f')
f[x] = hl.u8(x)
f.bound(x, 0, 1)
# Deliberate runtime error
buf = hl.Buffer(hl.UInt(8), [10])
try:
f.realize(buf)
except RuntimeError as e:
assert 'do not cover required region' in str(e)
else:
assert False, 'Did not see expected exception!'