Started code for DSP final project

6th-Semester-Spring-2024/DSP/Labs/FinalProject/statistical_based/confhyperg.m

@@ -0,0 +1,47 @@
+function z=confhyperg(a,b,x,n)
+% 
+% Computes the confluent hypergeometric function 
+% using a series expansion:
+%
+%    f(a,b;x)=
+%
+%    1 + [ab/1!c]x + [a(a+1)/2!b(b+1)]x^2 +
+%    [a(a+1)(a+2)/3!b(b+1)(b+2)]x^3 + ...
+%
+% The above series is expanded to n terms
+%
+% 
+%
+% Philipos C. Loizou
+
+if nargin ~= 4
+    error('Usage: confhyperg(a,b,x,n) - Incorrect number of arguments')
+end
+
+if (n <= 0 | n ~= floor(n))
+    error('Usage: confhyperg (a,b,c,x,n) - n has to be a positive integer')
+end
+
+NEG=0;
+if x<0
+    x=abs(x);
+    a=b-a;
+    NEG=1;   
+end
+
+z = 0;
+m = 0;
+while (m<n)
+    if (m == 0)
+        delta = 1;
+    else
+        delta = delta .* x .* (a + (m - 1))  ./ (m .* (b + (m-1)));  
+    end
+   
+   z = z + delta;
+   m = m + 1;
+end
+
+if NEG==1  % if x<0
+    z=exp(-x).*z;
+end;