Change preprocessing parameter in neural network

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Lova
Lova 2011-2-26
Hi!
I am using neural networks to reconstruct rainfall time series. Since the network sometimes generates negative rainfall, I would like to change the scaling in the preprossesing function 'mapminmax' to [0.1 0.9] instead of the default [-1 1].
To do this, I've tried to change the ymin and ymax reachable through processParams.
% Choose Input and Output Pre/Post-Processing Functions
net.inputs{1}.processFcns = {'removeconstantrows','mapminmax'};
net.outputs{2}.processFcns = {'removeconstantrows','mapminmax'};
net.inputs{1}.processParams{2} %Returns the parameters for 'mapminmax'
net.inputs{1}.processParams{2}(1).ymin %This returns -1
net.inputs{1}.processParams{2}(1).ymin = 0.1; %But I can't change the parameter
This code generates the following:
ans =
ymin: -1
ymax: 1
ans =
-1
??? Undefined function or variable "processParams".
Error in ==> network.subsasgn>network_subsasgn at 118
if isempty(err), [net,err] = setInputProcessParam(net,i,processParams); end
Error in ==> network.subsasgn at 11
net = network_subsasgn(net,subscripts,v,netname);
Error in ==> NNReconstructRain at 26
net.inputs{1}.processParams{2}(1).ymin = 0.1;
How can I change the value?
Thanks
Lova

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采纳的回答

Mark Hudson Beale
Mark Hudson Beale 2011-4-19
You can try this workaround:
net = struct(net);
net.inputs{1}.processParams{2}.ymin = 0.1;
net = network(net);

更多回答（1 个）

wonderboy
wonderboy 2011-9-15
i have the same problem in MATLAB r2010b. when i want to set the ymin or y max property of the mapminmax process function i get an error. see:
net.inputs{1}.processParams{3}.ymin = 0
??? Undefined function or variable "processParams".
however, on the r2010a, you won't see the above error.
i wonder sometimes, do the designing team test the product at all???!
the strange thing is that, in the HELP document, on advanced Topic/custom network, when they reach to this point, they skipped it! see (exact copy/paste from MATLAB Neural Network User Guide 7):
Set the second input vector ranges to be from -2 to 2 for five elements as follows:
net.inputs{1}.processFcns = {'removeconstantrows','mapminmax'};
View the new input properties. You will see that processParams, processSettings...
as you see on above they forgot to write this:
net.inputs{1].processFcns{2}.ymin = -2;
net.inputs{1].processFcns{2}.ymax = -2;
however, maybe they knew, this version's bug on this command!
this is really embarrassing.

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