Class 1 modify the besell Function

# Include "stdio. H "<br/> # include" math. H "<br/> /********************************* * ******************************* <br/> first-class variants bessert function/<br/> class-1 modify the Bessert function/<br/> class-1 Abnormal Bessert function/<br/> class-1 Virtual Volume Bessert function/<br /> Hyperbolic Shell functions <br/> ****************************** **********************************/<br/> double first_modified_bessel (int n, double X) <br/>{< br/> int I, m; <br/> double T, Y, P, B0, B1, Q; <br/> static double A [7] = {1. 0, 3.5156229, 3.0899424, 1.2067492, <br/> 0.2659732, 0.0360768, 0.0045813 }; <br/> static Double B [7] = {0.5, 0.87890594, 0.51498869, <br/> 0.15084934, 0.02658773, 0.00301532, 0.00032411}; <br/> static double C [9] = {0.39894228, 0.01328592, 0.00225319, <br/>-0.00157565, 0.00916281, -0.02057706, <br/> 0.02635537,-0.01647633, 0.00392377}; <br/> static double d [9] = {0.39894228,-0.03988024,-0.00362018, <br/> 0.00163801,-0.010 31555, 0.02282967, <br/>-0.02895312, 0.01787654,-0.00420059 };< br/> If (n <0) n =-N; <br/> T = FABS (x); <br/> If (n! = 1) <br/>{< br/> If (T <3.75) <br/>{< br/> Y = (x/3.75) * (x/3.75); P = A [6]; <br/> for (I = 5; I> = 0; I --) <br/> P = p * Y + A [I]; <br/>}< br/> else <br/>{< br/> Y = 3.75/T; P = C [8]; <br/> for (I = 7; I> = 0; I --) <br/> P = p * Y + C [I]; <br/> P = p * exp (T)/SQRT (t); <br/>}< br/> If (n = 0) return (p); <br/> q = P; <br/> If (T <3.75) <br/> {<br/> Y = (x/3.75) * (x/3.75); P = B [6]; <br/> for (I = 5; I> = 0; I --) P = p * Y + B [I]; <br/> P = p * t; <br/>}< br/> else <br/> {<br/> Y = 3.75/T; P = d [8]; <br/> for (I = 7; I> = 0; I --) P = p * Y + d [I]; <br/> P = p * exp (T)/SQRT (t); <br/>}< br/> If (x <0.0) P =-P; <br/> If (n = 1) Return (p); <br/> If (x = 0.0) Return (0.0 ); <br/> Y = 2.0/T; t = 0.0; b1 = 1.0; b0 = 0.0; <br/> M = N + (INT) SQRT (40.0 * n ); <br/> m = 2 * m; </P> <p> for (I = m; I> 0; I --) <br/> {<br/> P = b0 + I * y * B1; b0 = b1; b1 = P; <br/> If (FABS (B1)> 1.0e + 10) <br/>{< br/> T = T * 1.0e-10; b0 = b0 * 1.0e-10; <br/> b1 = b1 * 1.0e-10; <br/>}< br/> if (I = N) t = b0; <br/>}< br/> P = T * q/B1; <br/> If (x <0.0) & (N % 2 = 1 )) P =-P; <br/> return (p); <br/>}< br/> main () <br/>{< br/> int N; <br/> double X; <br/> double y0, Y1, Y2, Y3, Y4; <br/> file * fp = fopen ("D: // data.txt ", "W"); <br/> fprintf (FP, "x I0 (x) i1 (x) I2 (x) I3 (x) I4 (X)/n "); <br/> for (x = 0.0; x <6; x + = 0.01) <br/> {<br/> Y0 = first_modified_bessel (0, x ); <br/> Y1 = first_modified_bessel (1, x); <br/> Y2 = first_modified_bessel (2, x); <br/> Y3 = first_modified_bessel (3, X ); <br/> Y4 = first_modified_bessel (4, x); <br/> fprintf (FP, "% 6.3f % 6.3f % 6.3f % 6.3f % 6.3f % 6.3f/N", X, y0, Y1, Y2, Y3, Y4); <br/>}< br/> fprintf (FP, "/N"); <br/> fclose (FP ); <br/>}< br/> 

 

Plot the TXT data as follows: