What is the 'Yes No' error code???

ns=10;

face=10000;
val_date='04-02-2007';
mid_date= ['09-05-2007';'03-05-2008';'09-05-2008';'03-05-2009'];

strike=[0.9 0.85 0.8 0.75];

c_rate=[0.055 0.11 0.165 0.22];

dummy=0.16;
ki=0.6;
ki_YesNo='No'         %HERE

ref_S= [48300 86800];
S=[45800 84600]; 
r=0.05;
vol=[0.25 0.3];
rho=0.5;
q=[0.01 0.01];

temp_ch=datenum(mid_date)'-datenum(val_date);

mid_ch=temp_ch(find(temp_ch>=0));

c_rate=c_rate(find(temp_ch>=0));
strike=strike(find(temp_ch>=0));

N=mid_ch(end);
dt=1/365;
mid_size=length(mid_ch);

payment=zeros(ns,mid_size);

for i =1:ns
    for j=1:mid_size
        payment(i,j)=face*(1+c_rate(j));
    end
end



corr=[1 rho;rho 1];
M=chol(corr);

SP1=zeros(ns,N+1);
SP1(:,1)=S(1);
SP2=zeros(ns,N+1);
SP2(:,1)=S(2);

for i=1:ns
    w0=randn(N,2);
    w=w0*M;
    for j=2:N+1
    	SP1(i,j)=SP1(i,j-1)*exp((r-q(1)-vol(1)^2/2)*dt+...
    		vol(1)*sqrt(dt)*w(j-1,1));
    	SP2(i,j)=SP2(i,j-1)*exp((r-q(2)-vol(2)^2/2)*dt+...
    		vol(2)*sqrt(dt)*w(j-1,2));
    end
end

R1=SP1/ref_S(1);
R2=SP2/ref_S(2);
WP=min(R1,R2);

strike_ch=WP(:,mid_ch+1);
payoff=zeros(ns,mid_size);

for i=1:ns
    for j=1:mid_size
        if strike_ch(i,j)>=strike(j)
    		payoff(i,j)=payment(i,j);
    		break
        end
    end
    continue
end

for i=1:ns
    if payoff(i,:)==0
        switch ki_YesNo
            case 'NO'
                ki_event=any(WP(i,:)<ki);
                if ki_event==1
                    payoff(i,end)=face*WP(i,end);
                else
                    payoff(i,end)=face*(1+dummy);
                end
            case 'Yes'
                payoff(i,end)=face*WP(i,end);
            otherwise
                error('ki_YesNO = Yes or No');
        end
    end
end

exp_payoff=mean(payoff);

disc_payoff=zeros(1,mid_size);
for j=1:mid_size
    disc_payoff(j)=exp_payoff(j)*exp(-r*mid_ch(j)/365);
end

ELS_Price=sum(disc_payoff);

-----------------------------

in this code, There are "ki_YesNO = Yes or No" problem code was out. With the teaching plan i just write down correctly... What's the problem

Answer 1

[Voss]

ki_YesNo='No'

ki_YesNo = 'No'

% ...

switch ki_YesNo
    case 'NO'
        % ...
    case 'Yes'
        % ...
    otherwise
        error('ki_YesNO = Yes or No');
end

ki_YesNO = Yes or No

Notice that's switch 'NO' (with an upper-case O), but ki_YesNo is 'No' (lower-case o). 'No' is not the same as 'NO', and 'No' is not the same as 'Yes', so the code went to the otherwise branch and the error was thrown.

If you want the match to be case-insensitive, so that 'no', 'No', 'NO', and 'nO' all go to the 'NO' branch (and similarly 'yes', 'YES', 'yEs', etc., all go to the 'Yes' branch), one way to do that is:

switch lower(ki_YesNo) % make lower-case
    case 'no' % check against lower-case
        % ...
    case 'yes'
        % ...
    otherwise
        error('ki_YesNO = Yes or No');
end