function?checkNNGradients（lambda）
%CHECKNNGRADIENTS?Creates?a?small?neural?network?to?check?the
%backpropagation?gradients
%???CHECKNNGRADIENTS（lambda）?Creates?a?small?neural?network?to?check?the
%???backpropagation?gradients?it?will?output?the?analytical?gradients
%???produced?by?your?backprop?code?and?the?numerical?gradients?（computed
%???using?computeNumericalGradient）.?These?two?gradient?computations?should
%???result?in?very?similar?values.
%

if?~exist（‘lambda‘?‘var‘）?||?isempty（lambda）
????lambda?=?0;
end

input_layer_size?=?3;
hidden_layer_size?=?5;
num_labels?=?3;
m?=?5;

%?We?generate?some?‘random‘?test?data
Theta1?=?debugInitializeWeights（hidden_layer_size?input_layer_size）;
Theta2?=?debugInitializeWeights（num_labels?hidden_layer_size）;
%?Reusing?debugInitializeWeights?to?generate?X
X??=?debugInitializeWeights（m?input_layer_size?-?1）;
y??=?1?+?mod（1:m?num_labels）‘;

%?Unroll?parameters
nn_params?=?[Theta1（:）?;?Theta2（:）];

%?Short?hand?for?cost?function
costFunc?=?@（p）?nnCostFunction（p?input_layer_size?hidden_layer_size?...
???????????????????????????????num_labels?X?y?lambda）;

[cost?grad]?=?costFunc（nn_params）;
numgrad?=?computeNumericalGradient（costFunc?nn_params）;

%?Visually?examine?the?two?gradient?computations.??The?two?columns
%?you?get?should?be?very?similar.?
disp（[numgrad?grad]）;
fprintf（[‘The?above?two?columns?you?get?should?be?very?similar.\n‘?...
?????????‘（Left-Your?Numerical?Gradient?Right-Analytical?Gradient）\n\n‘]）;

%?Evaluate?the?norm?of?the?difference?between?two?solutions.??
%?If?you?have?a?correct?implementation?and?assuming?you?used?EPSILON?=?0.0001?
%?in?computeNumericalGradient.m?then?diff?below?should?be?less?than?1e-9
diff?=?norm（numgrad-grad）/norm（numgrad+grad）;

fprintf（[‘If?your?backpropagation?implementation?is?correct?then?\n‘?...
?????????‘the?relative?difference?will?be?small?（less?than?1e-9）.?\n‘?...
?????????‘\nRelative?Difference:?%g\n‘]?diff）;

end

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????1950??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\checkNNGradients.m

?????文件???????1095??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\computeNumericalGradient.m

?????文件????????841??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\debugInitializeWeights.m

?????文件???????1502??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\displayData.m

?????文件???????8263??2017-12-10?10:20??machine-learning-ex4\machine-learning-ex4\ex4\ex4.m

?????文件????7511764??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\ex4data1.mat

?????文件??????79592??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\ex4weights.mat

?????文件???????8749??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\fmincg.m

?????文件???????1624??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\AUTHORS.txt

?????文件???????3862??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\ChangeLog.txt

?????文件????????881??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\jsonopt.m

?????文件???????1551??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\LICENSE_BSD.txt

?????文件??????18732??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\loadjson.m

?????文件??????15574??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\loadubjson.m

?????文件????????771??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\mergestruct.m

?????文件??????19369??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\README.txt

?????文件??????17462??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\savejson.m

?????文件??????16123??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\saveubjson.m

?????文件???????1094??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\varargin2struct.m

?????文件???????1195??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\makeValidFieldName.m

?????文件???????5562??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\submitWithConfiguration.m

?????文件???????5633??2017-12-10?09:53??machine-learning-ex4\machine-learning-ex4\ex4\nnCostFunction.m

?????文件????????585??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\predict.m

?????文件????????985??2017-12-09?10:05??machine-learning-ex4\machine-learning-ex4\ex4\randInitializeWeights.m

?????文件????????137??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\sigmoid.m

?????文件????????739??2017-12-09?09:58??machine-learning-ex4\machine-learning-ex4\ex4\sigmoidGradient.m

?????文件???????1635??2017-12-08?16:48??machine-learning-ex4\machine-learning-ex4\ex4\submit.m

?????文件????????262??2017-12-10?10:22??machine-learning-ex4\machine-learning-ex4\ex4\token.mat

?????文件?????356692??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4.pdf

?????目錄??????????0??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab

............此處省略7個文件信息