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
-----------?---------??----------?-----??----
?????目錄???????????0??2019-03-02?17:43??machine-learning-ex4\
?????目錄???????????0??2019-03-02?17:43??machine-learning-ex4\machine-learning-ex4\
?????目錄???????????0??2019-03-02?17:43??machine-learning-ex4\machine-learning-ex4\ex4\
?????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????????8099??2017-03-13?18:40??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
?????目錄???????????0??2019-03-02?17:43??machine-learning-ex4\machine-learning-ex4\ex4\lib\
?????目錄???????????0??2019-03-02?17:43??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\
?????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????????1551??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\LICENSE_BSD.txt
?????文件???????19369??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\README.txt
?????文件?????????881??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\lib\jsonlab\jsonopt.m
?????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???????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????????3210??2017-03-13?18:40??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?????????903??2017-03-13?18:40??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?????????677??2017-03-13?18:40??machine-learning-ex4\machine-learning-ex4\ex4\sigmoidGradient.m
............此處省略2個文件信息