From 76378eb2c4f9b71fcfefa18239197b89230f7ae1 Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Thu, 29 Jul 2021 20:52:29 +0100 Subject: [PATCH] sigh, I-DCT had to reverse the order of middle loop to stop overwrite-accumulation of iterative sum --- src/openpower/decoder/isa/fastdct-test.py | 2 +- src/openpower/decoder/isa/fastdctlee.py | 12 +++++++----- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/src/openpower/decoder/isa/fastdct-test.py b/src/openpower/decoder/isa/fastdct-test.py index be786aa5..d9031813 100644 --- a/src/openpower/decoder/isa/fastdct-test.py +++ b/src/openpower/decoder/isa/fastdct-test.py @@ -28,7 +28,7 @@ import fastdctlee, naivedct, remap_dct_yield class FastDctTest(unittest.TestCase): def test_fast_dct_lee_vs_naive(self): - for i in range(2, 3): + for i in range(3, 8): n = 2**i vector = FastDctTest.nonrandom_vector(n) expect = naivedct.transform(vector) diff --git a/src/openpower/decoder/isa/fastdctlee.py b/src/openpower/decoder/isa/fastdctlee.py index 81631050..719c4c93 100644 --- a/src/openpower/decoder/isa/fastdctlee.py +++ b/src/openpower/decoder/isa/fastdctlee.py @@ -362,13 +362,14 @@ def inverse_transform_iter(vec): # first the outer butterfly (iterative sum thing) n = len(vec) - size = n // 2 - while size >= 2: + size = 2 + while size <= n: halfsize = size // 2 ir = list(range(0, halfsize)) print ("itersum", halfsize, size, ir) for i in ir: jr = list(range(i+halfsize, i+n-halfsize, size)) + jr.reverse() print ("itersum jr", i+halfsize, i+size, jr) for jh in jr: x = vec[jh] @@ -376,7 +377,7 @@ def inverse_transform_iter(vec): vec[jh+size] = x + y print (" itersum", size, i, jh, jh+size, x, y, "jh+sz", vec[jh+size]) - size //= 2 + size *= 2 print("transform2-inv post-itersum", vec) @@ -460,8 +461,9 @@ def inverse_transform2(vector, root=True, indent=0): for i in range(2, n, 2): alpha.append(vector[i]) beta.append(vector[i - 1] + vector[i + 1]) - print (idt, " alpha", alpha) - print (idt, " beta", beta) + print (idt, " alpha", i, vector[i]) + print (idt, " beta", i-1, i+1, vector[i-1], vector[i+1], "->", + beta[-1]) inverse_transform2(alpha, False, indent+1) inverse_transform2(beta , False, indent+1) for i in range(half): -- 2.30.2