I don't understand, what Import
does with CDF.
If I enter
In[17]:= data = Import[ExampleFile]
Out[17]= {"Pose"}
what I can do with returned object? How can I return Pose
entry only?
If I try to specify this as element name as string, I am failing:
In[18]:= data = Import[ExampleFile, "Pose"]
During evaluation of In[18]:= Import::noelem: The Import element "Pose" is not present when importing as NASACDF.
Out[18]= $Failed
UPDATE
I noticed, that it showed entity name in quotes. In notebook it looks different:
i.e. w/o quotes.
UDPATE 2
Shared example: https://drive.google.com/open?id=0By8pZ9a2478YOGlhZUlRU3VNb28
UPDATE 3
Apparently Mathematica has a bug here, because the data returned is reshaped incorrectly.
Here is Matlab transcript, reading the same file:
>> data = cdfread(ExampleFile,'Variable', {'Pose'});
>> data = data{1};
>> size(data)
ans =
992 96
>> data(1,1:5)
ans =
1×5 single row vector
-287.2470 64.5002 933.7140 -417.2063 37.0789
>> data(1:5,1)
ans =
5×1 single column vector
-287.2470
-287.6960
-288.1260
-288.5740
-288.9960
An here is Mathematicas:
In[47]:= data = Import[ExampleFile, "Elements"]
data = Import[ExampleFile, "Data"];
Dimensions[data]
data[[1, 1, 1, 1]]
Out[47]= {"Annotations", "Data", "DataEncoding", "DataFormat", \
"Datasets", "Metadata"}
Out[49]= {1, 1, 992, 96}
Out[50]= -287.247
data[[1, 1, 1, Range[5]]]
Out[54]= {-287.247, -287.696, -288.126, -288.574, -288.996}
In[55]:= data[[1, 1, Range[5], 1]]
Out[55]= {-287.247, -497.341, -378.209, -376.513, -370.388}
I.e. although Mathematica indicates the similar shape of data, i.t. fills that shape in different way.
I.e. what Matlab cosiders as row, Mathematica considers as column, and what Mathematica considers as column, is unknown.
So, I still need instructions if I am incorrectly operating with Mathematica's ND arrays, or, if it is Mathematica bug, I need to know, how to recover from it.
UPDATE 4
For now I see the following way to recover original data from corrupted one:
dims = Dimensions[data]
data = ArrayReshape[
data, {dims[[1]], dims[[2]], dims[[4]], dims[[3]]}];
data = Transpose[data, {1, 2, 4, 3}];
Answer
In WL this format is known as NASACDF
In doubt you can always import "Elements"
and try each one:
Import["Posing.cdf", "Elements"]
{"Annotations", "Data", "DataEncoding", "DataFormat", "Datasets", "Metadata"}
Import["Posing.cdf", "Data"]
Initially returned {"Pose"}
was a list of datasets stored in a file. You can extract specific dataset via:
Import["Posing.cdf", {"Datasets", "Pose"}]
All that and more can of course be learned from linked documentation page.
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