MATLAB: Convolution built-in function

#matlab #convolution #error

What are conv function updates as I can't run this code conv(RC,plot(amp)) without error Error: using conv2 Invalid data type. First and second arguments must be numeric or logical., Thing do not happen in version 13 !!

Best Answer

What John and Stephen said. What you appear to want (and wanted originally) is just
synthetic=conv(RC,amp);
which would be the convolution of RC and the amp kernel.
Prior to HG2 (handle graphics 2), graphics and other handles were just numeric values (doubles) so arithmetic operations on them were not illegal and so you didn't get an error in earlier release but the answer was nonsensical. Now, handles are a new class and so such erroneous operations can be flagged as errors.
You will want to revisit any calculations done earlier as they are in error; the result would have been just a constant times the vector.
R2012b
>> h=plot(rand(4,1))
h =
174.0016
>> whos h
Name      Size            Bytes  Class     Attributes
h         1x1                 8  double              
>> conv(h,1:4)
ans =
174.0016  348.0032  522.0048  696.0063
>> [1:4]*h
ans =
174.0016  348.0032  522.0048  696.0063
>> 
R2014b
>> h=plot(rand(3,1))
>> h
h = 
Line with properties:
 ...
>> whos h
Name      Size            Bytes  Class                                   Attributes
h         1x1                60  matlab.graphics.chart.primitive.Line              
>> 
>> double(h)
ans =
 1.2207e-04
>>
So, you see that prior to HG2 plot returned a double that was a floating point value; the specific value is dependent upon each invocation, but 175+/- is typical. OTOH, with HG2 as R2014b shows, the handle is a class variable and you can't see the numeric value unless you cast it to double and you see the numeric value is grossly different.
Either, way, using the line handle in conv makes no sense computationally, whatsoever.
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