New Recursion Issue

Question

Andrew 2011-2-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1235-new-recursion-issue

采纳的回答： Oleg Komarov

在 MATLAB Online 中打开

Hi everyone,

Having issues with my same program just I can't seem to see the error again since i have all the conditions I think...

Codes:

main:

close all
clear all
clc
theta = [-pi:pi/100:pi]';
plotValues = cos(theta);
lamda = [0:(2*pi)/100:(2*pi)]';
set1 = pnmnew(1,1,theta,1);
set2 = pnmnew(3,1,theta,1);
set3 = pnmnew(5,1,theta,1);
set4 = pnmnew(7,1,theta,1);
hold on
plot(plotValues,set1,'g');
plot(plotValues,set2,'r');
plot(plotValues,set3,'m');
plot(plotValues,set4,'b');
axis([-1 1 -4 4]);
legend('n=1; m=1','n=3; m=1', 'n=5; m=1', 'n=7; m=1')
hold off
set1non = pnmnew(1,1,theta,0);
set2non = pnmnew(3,1,theta,0);
set3non = pnmnew(5,1,theta,0);
set4non = pnmnew(7,1,theta,0);
figure
hold on
plot(plotValues,set1non,'g');
plot(plotValues,set2non,'r');
plot(plotValues,set3non,'m');
plot(plotValues,set4non,'b');
axis([-1 1 -4 4]);
legend('n=1; m=1','n=3; m=1', 'n=5; m=1', 'n=7; m=1')
%RnmZ = pnmnew(4,0,theta,1)*cos(0*lamda);
SnmZ = pnm(4,0,theta,1)*sin(0*lamda);

pnm:

function [ values ] = pnmnew( n,m,theta,norm )
if ( norm == 0 ) 
      if ( m == 0)
          syms q
          diffe = (cos(q)^2-1)^n;
          diffe = diff(diffe,n);
          diffe = subs(diffe,q,theta);
          values = (1/((2^n)*factorial(n)))* diffe;
      else
          syms t
          differ = (cos(t)^2-1)^n;
          differ = diff (differ,n+m);
          differ = subs(differ,t,theta);
          values = (1/((2^n)*factorial(n))).*((1-cos(theta).^2).^(m/2)).*differ;  
      end
elseif (norm == 1)
      if ( n == 1 && m == 1)  
           w11 = sqrt(3);
           values = w11*sqrt((1-cos(theta).^2))*pnm(m-1,m-1,theta,norm);
      elseif ( n == 0 && m == 0)
          values = 1;
      elseif ( n==0 && m~=0 )
          wnm = sqrt(((2*n+1)*(2*n-1))/((n+m)*(n-m)));
          wnmB = sqrt(((2*(n-1)+1)*(2*(n-1)-1))/(((n-1)+m)*((n-1)-m)));
          values = wnm*(cos(theta).*pnm(n-1,m,theta,norm)-(wnmB)^(-1)*pnm(n-2,m,theta,norm));          
      elseif ( m==0 && n~=0)
          values = (-(n-1)/n)*pnm(n-2,m,theta,norm)+((2*n-1)/n)*cos(theta)*pnm(n-1,m,theta,norm);
      elseif (n == m && (n~=1 && m~=1))
          wmm = sqrt((2*m-1)/(2*m));
          values = wmm.*(1-cos(theta).^2).^(1/2)*pnm(m-1,m-1,theta,norm);
      elseif (n <0 || m < 0)
          values = 1;
      elseif ( n ~= m  )
          wnm = sqrt(((2*n+1)*(2*n-1))/((n+m)*(n-m)));
          wnmB = sqrt(((2*(n-1)+1)*(2*(n-1)-1))/(((n-1)+m)*((n-1)-m)));
          values = wnm*(cos(theta).*pnm(n-1,m,theta,norm)-(wnmB)^(-1)*pnm(n-2,m,theta,norm));
      end
  end
end

I'm pretty sure the issue is something to do with m = 0 and n = 0 but I already have my condition for that so I don't know whats wrong. Matlab just give sme the recursion limit error

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Answer 1

Oleg Komarov 2011-2-11

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1235-new-recursion-issue#answer_1770

Ok, you created pnmnew, but inside you call pnm, which in my case still doesn't handle negative m or n as I pointed out in 1227-recursion-issue

Oleg

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Andrew 2011-2-11

Oh I didn't realize I was still calling pnm within my new function I changed it according to what you said last time but didn't change all my functions names. Thanks!

I'm getting the correct plots not. I might have to post again if I hit another condition error though. xD

Thanks for the help

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