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I am trying to use Mathematica's wavelet transform. In preparation I entered:

n = 8
Clear[dataTest]
dataTest = Table[0, {n}]
For [i = 1, i < n + 1, i++,
 dataTest[[i]] = i;
 ]
dataTest
wave2 = DaubechiesWavelet[2]
dwd = DiscreteWaveletTransform[dataTest, wave2]
dwd[All]

and had output:

...
{{0} -> {10.0382, 2.31079, 5.13922, 7.96764, 10.0382}, 
 {1} -> {-2.82843, 4.44089*10^-16, 0., 0., -2.82843}, 
 {0, 0} -> {14.1962, 6.90192, 10.0981, 13.0981}, 
 {0, 1} -> {4., -1.36603, 1.09808, -4.09808}, 
 {0, 0, 0} -> {18.1226, 13.1982, 18.1226}, 
 {0, 0, 1} -> {4.2993, -1.26282, 4.2993}}

When I calculate the transform by hand I obtain:

{0} -> {2.31079, 5.13922, 7.96764, 10.0382},...,
{0, 0} -> {5.901923789, 12.09807621},...,
{0, 0, 0} -> {12.72792206}

In addition to the numerical differences, I thought {0} should have 4 values, {0, 0} should have 2 values and {0, 0, 0} should have 1 value for input data of dimension 8. Can anyone help me understand the discrepancies?

In addition I tried input data of dimension 4:

n = 4
Clear[dataTest]
dataTest = Table[0, {n}]
For [i = 1, i < n + 1, i++,
 dataTest[[i]] = i;
 ]
dataTest
wave2 = DaubechiesWavelet[2]
dwd = DiscreteWaveletTransform[dataTest, wave2]
dwd[All]
dwd["EnergyFraction"]

resulting in output:

... {{0} -> {4.76028, 2.31079, 4.76028}, {1} -> {-1.41421, 4.44089*10^-16, -1.41421}, {0, 0} -> {5.86603, 4.68301, 6.18301}, {0, 1} -> {1.5, 0.549038, -2.04904}}

{{1} -> 0.0379793, {0, 1} -> 0.0640901, {0, 0} -> 0.897931}

The input energy is 1*1+2*2+3*3+4*4=30. Consequently the last line cannot be correct since the EnergyFraction for {1} should be (1.41421*1.41421)/30 = 2/(30) = 0.066666667, definitely NOT 0.0379793. Alternately, note that (1.41421*1.41421)/(0.0379793) = 52.66026, which is significantly greater than the input energy.

cadri
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