Page 530 - Design and Operation of Heat Exchangers and their Networks

Appendix 513

function G0 = special_function_G0 (x, y)
% G0(x,y)=exp(-x-y)∗sum(m = 1:Inf;k = 0:m-1)(y m/m!)∗(x k/k!)
^
^
if (x == 0)
G0 = 1 - exp(- y);
elseif (y == 0)
G0 = 0;
else
m=1;
sx = 1;
sy = 0;
ay = 1;
while (abs(sx) > abs(sy) ∗ 1E-8)
ay = ay ∗ y/m;% y m/m!
^
ax = ay;
sx = ay;
for k=1:m- 1
^
^
ax = ax ∗ x / k; % (y m/m!)∗(x k/k!)
sx = sx + ax;
end
sy = sy + sx;
m=m+ 1;
end
G0 = exp(- x - y) ∗ sy;
end
end
function F_1 = special_function_F_1 (x, y)
if (x == 0)
F_1 = 0;
elseif (y == 0)
F_1 = x ∗ exp(- x);
else
m=1;
s=x;
a=x;
while (abs(a) > abs(s) ∗ 1E-8)
a=a ∗ x ∗ y/m/(m + 1);
s=s+ a;
m=m+ 1;
end