function?[]?=?checkNumericalGradient（）
%?This?code?can?be?used?to?check?your?numerical?gradient?implementation?
%?in?computeNumericalGradient.m
%?It?analytically?evaluates?the?gradient?of?a?very?simple?function?called
%?simpleQuadraticFunction?（see?below）?and?compares?the?result?with?your?numerical
%?solution.?Your?numerical?gradient?implementation?is?incorrect?if
%?your?numerical?solution?deviates?too?much?from?the?analytical?solution.
??
%?Evaluate?the?function?and?gradient?at?x?=?[4;?10];?（Here?x?is?a?2d?vector.）
x?=?[4;?10];
[value?grad]?=?simpleQuadraticFunction（x）;

%?Use?your?code?to?numerically?compute?the?gradient?of?simpleQuadraticFunction?at?x.
%?（The?notation?“@simpleQuadraticFunction“?denotes?a?pointer?to?a?function.）
numgrad?=?computeNumericalGradient（@simpleQuadraticFunction?x）;

%?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?2.1452e-12?
diff?=?norm（numgrad-grad）/norm（numgrad+grad）;
disp（diff）;?
fprintf（‘Norm?of?the?difference?between?numerical?and?analytical?gradient?（should?be?end


??
function?[valuegrad]?=?simpleQuadraticFunction（x）
%?this?function?accepts?a?2D?vector?as?input.?
%?Its?outputs?are:
%???value:?h（x1?x2）?=?x1^2?+?3*x1*x2
%???grad:?A?2x1?vector?that?gives?the?partial?derivatives?of?h?with?respect?to?x1?and?x2?
%?Note?that?when?we?pass?@simpleQuadraticFunction（x）?to?computeNumericalGradients?we‘re?assuming
%?that?computeNumericalGradients?will?use?only?the?first?returned?value?of?this?function.

value?=?x（1）^2?+?3*x（1）*x（2）;

grad?=?zeros（2?1）;
grad（1）??=?2*x（1）?+?3*x（2）;
grad（2）??=?3*x（1）;

end

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2011-01-06?02:46??starter\
?????目錄???????????0??2011-01-04?05:38??starter\minFunc\
?????文件????????3251??2011-01-04?05:39??starter\minFunc\ArmijoBacktrack.m
?????文件?????????807??2011-01-04?05:39??starter\minFunc\autoGrad.m
?????文件?????????901??2011-01-04?05:39??starter\minFunc\autoHess.m
?????文件?????????317??2011-01-04?05:39??starter\minFunc\autoHv.m
?????文件?????????870??2011-01-04?05:39??starter\minFunc\autoTensor.m
?????文件?????????385??2011-01-04?05:39??starter\minFunc\callOutput.m
?????文件????????1845??2011-01-04?05:39??starter\minFunc\conjGrad.m
?????文件?????????995??2011-01-04?05:39??starter\minFunc\dampedUpdate.m
?????文件????????2421??2011-01-04?05:39??starter\minFunc\example_minFunc.m
?????文件????????1604??2011-01-04?05:39??starter\minFunc\example_minFunc_LR.m
?????文件?????????107??2011-01-04?05:39??starter\minFunc\isLegal.m
?????文件?????????924??2011-01-04?05:39??starter\minFunc\lbfgs.m
?????文件????????2408??2011-01-04?05:39??starter\minFunc\lbfgsC.c
?????文件????????7707??2011-01-04?05:39??starter\minFunc\lbfgsC.mexa64
?????文件????????7733??2011-01-04?05:39??starter\minFunc\lbfgsC.mexglx
?????文件????????9500??2011-01-04?05:39??starter\minFunc\lbfgsC.mexmac
?????文件????????7168??2011-01-04?05:39??starter\minFunc\lbfgsC.mexw32
?????文件????????9728??2011-01-04?05:39??starter\minFunc\lbfgsC.mexw64
?????文件?????????614??2011-01-04?05:39??starter\minFunc\lbfgsUpdate.m
?????目錄???????????0??2011-01-04?05:38??starter\minFunc\logistic\
?????文件?????????417??2011-01-04?05:39??starter\minFunc\logistic\LogisticDiagPrecond.m
?????文件?????????216??2011-01-04?05:39??starter\minFunc\logistic\LogisticHv.m
?????文件?????????659??2011-01-04?05:39??starter\minFunc\logistic\LogisticLoss.m
?????文件????????1154??2011-01-04?05:39??starter\minFunc\logistic\mexutil.c
?????文件?????????317??2011-01-04?05:39??starter\minFunc\logistic\mexutil.h
?????文件?????????227??2011-01-04?05:39??starter\minFunc\logistic\mylogsumexp.m
?????文件????????3965??2011-01-04?05:39??starter\minFunc\logistic\repmatC.c
?????文件????????7680??2011-01-04?05:39??starter\minFunc\logistic\repmatC.dll
?????文件???????20682??2011-01-04?05:39??starter\minFunc\logistic\repmatC.mexglx
............此處省略26個文件信息