I'm trying to compile this matlab code,
`
lambda = 1/pi;
delta = 3;
alpha = 3.5;
sum = 0;
syms t;
for k = 1:5
for l = 0:(k*delta)
for m = 1:2
a = ((lambda*pi)^(l+(alpha/2)+(m*delta)+1))/(factorial(l)*factorial((k*delta) -1)*factorial(m*delta));
gamma = # (t) exp(-t).*t.^((k*delta)-l-(alpha/2));
f = # (u) int(gamma,t,u,inf);
g = #(u) u.^((2*l) - alpha + (2*m*delta+1));
h = #(u) a.*g(u).*f(u);
b = integral(#(u) h(u),0,inf);
sum = sum +b ;
end
end
end
sum
I get this error,
Error using mupadmex
Error in MuPAD command: The argument is invalid. [Dom::Interval::new]
anyone have an idea how to solve this problem ?
Many thanks,
Related
Basically I would like to use the fsolve command in order to find the roots of an equation.
I think I should create a function handle that evaluates this equation in the form "right hand side - left hand side =0", but I've been struggling to make this work. Does anyone know how to do this?
The equation itself is 1/sqrt(f) = -1.74log((1.254/((1.27310^8)sqrt(f)))+((110^-3)/3.708)). So I would like to find the point of intersection of the left and right side by solving for 1/sqrt(f)+(1.74log((1.254/((1.27310^8)sqrt(f)))+((110^-3)/3.708))) = 0 using fsolve.
Thanks a lot!
The code so far (not working at all)
f = #(x) friction(x,rho,mu,e,D,Q, tol, maxIter) ;
xguess = [0, 1];
sol = fsolve(x, xguess ) ;
function y = friction(x,rho,mu,e,D,Q, tol, maxIter)
D = 0.1;
L = 100
rho = 1000;
mu = 0.001;
e = 0.0001;
Q = 0.01;
U = (4*Q)/(pi*D^2);
Re = (rho*U*D)/mu ;
y = (1/sqrt(x))-(-1.74*log((1.254/(Re*sqrt(x)))+((e/D)/3.708)))
end
Error message:
Error using lsqfcnchk (line 80)
FUN must be a function, a valid character vector expression, or an inline function object.
Error in fsolve (line 238)
funfcn = lsqfcnchk(FUN,'fsolve',length(varargin),funValCheck,gradflag);
Error in Untitled (line 6)
sol = fsolve(x, xguess ) ;
opt = optimset('Display', 'Iter');
sol = fsolve(#(x) friction(x), 1, opt);
function y = friction(x)
D = 0.1;
L = 100; % note -- unused
rho = 1000;
mu = 0.001;
e = 0.0001;
Q = 0.01;
U = (4*Q)/(pi*D^2);
Re = (rho*U*D)/mu ;
y = (1/sqrt(x))-(-1.74*log((1.254/(Re*sqrt(x)))+((e/D)/3.708)));
end
sol = 0.0054
the first argument of fsolve should be the function not variable. Replace:
sol = fsolve(x, xguess );
with
sol = fsolve(f, xguess );
And define Rho, mu, e etc before you define f (not inside the friction function).
The following is a snippet from a function I am defining:
function [V1, V2] = lambert(R1, R2, t, string)
r1 = norm(R1);
r2 = norm(R2);
z = -100;
while F(z,t) < 0
z = z + 0.1;
end
tol = 1.e-8;
nmax = 5000;
ratio = 1;
n = 0;
while (abs(ratio) > tol) & (n <= nmax)
n = n + 1;
ratio = F(z,t)/dFdz(z);
z = z - ratio;
end
f = 1 - y(z)/r1;
g = A*sqrt(y(z)/mu);
gdot = 1 - y(z)/r2;
V1 = (R2-f*R1)/g;
V2 = (gdot*R1-R1)/g;
function dum = y(z)
dum = r1 + r2 + A*(z*S(z) - 1)/sqrt(C(z));
end
When I run this code with some vectors R1, R2, I get:
Error using *.
Inner matrix dimensions must agree.
This occurs at these lines:
V1 = (R2-f*R1)/g;
V2 = (gdot*R1-R1)/g;
I think this is due to the fact that f and gdot and g are matrices whose dimensions are incompatible with R1 and R2. However, as I have defined them, they should simply be scalars. I do not understand what in the code causes them to be matrices.
I've tried using .* instead of * etc, but with no success.
**I want to plot an array vector having symbolic variables in it. But I am getting an error which is given below.
??? Error using ==> plot
Conversion to double from sym is not possible.
Error in ==> dsolvenew at 36
plot(t2,qn2) **
The code is given below.
syms A Epsilon0 k1 k2 e s d R s f T c0 v0 v
An = 0.5*10^(-9);
Epsilon0n = 8.85*10^-12;
k1n = 10;
k2n = 10;
en = 1.6*10^-19;
sn = 1.8*10^(-9);%m gap size%
dn = 3*sn; % total distance
Rn = 1;
c0n=(An*Epsilon0n*k1n)/dn;
t1=0:0.1:5;
fn=1000;
v0n=7.5;
Tn=5/f;
vn=v0n*sin(2*3.14*fn*t1);
plot(t1,vn);
inits = 'q(0)=(20*10^(-20)),Q(0)=0';
[q,Q] = dsolve('Dq=((v/R)-(1/R)*(((d*q)+(s*Q))/(c0*d)))','DQ= (((q+Q)/(A*Epsilon0*k1))*s)',inits);
qn1=vpa(subs(q,{A,Epsilon0,k1,k2,e,s,d,R,c0}, {An,Epsilon0n,k1n,k2n,en,sn,dn,Rn,c0n}),3);
i=1;
while i<length(t1);
qn2(i)=subs(qn1, v, vn(i));
i=i+1;
end
t2=t1(1:50);
plot(t2,qn2)
I have this tiny program in Matlab.
laMatriz.m
function k = laMatriz(X)
Y = 9;
A = zeros(X, Y);
for i=1:X
V = elVector(Y);
LimY = length(elVector);
for j=1:LimY
A(i,j) = V(j);
end
end
k = A;
end
elVector.m
function elVector = elVector(N)
%fprintf('largo de elVector %i\n', N);
elVector=1:N;
end
Calling function laMatriz(10) results in this error:
??? Input argument "N" is undefined.
Error in ==> elVector at 3
elVector=1:N;
Error in ==> laMatriz at 11
LimY = length(elVector);
why? how can i fix it?
The problem is in this function:
function k = laMatriz(X)
Y = 9;
A = zeros(X, Y);
for i=1:X
V = elVector(Y);
LimY = length(elVector); <-- here you are calling length(elVector)
for j=1:LimY
A(i,j) = V(j);
end
end
k = A;
end
elVector is a function so you cannot call length with it. Did you mean length(V)? Basically your error is saying the argument N to the function elVector doesn't exist.
I want to solve equations in matlab, eg.
100+a/2=173*cos(b)
sqrt(3)*a/2=173*sin(b）
and the code would be:
[a,b]=solve('100+a/2=173*cos(b)','sqrt(3)*a/2=173*sin(b)','a','b')
However, if I want to take 100 as a variable, like
for k=1:100
[a,b]=solve('k+a/2=173*cos(b)','sqrt(3)*a/2=173*sin(b)','a','b')
end
There would be an error, how to make it?
degree=140/1000000;
p=42164000;
a=6378136.5;
b=6356751.8;
x_1=0;
y_1=p;
z_1=0;
for i=451:550
for j=451:550
alpha=(1145-i)*degree;
beta=(1145-j)*degree;
x_2=p/cos(alpha)*tan(beta);
y_2=0;
z_2=p*tan(alpha);
syms x y z x_1 x_2 y_1 y_2 z_1 z_2 a b
eq = [(x-x_1)*(y2-y_1)-(x_2-x_1)*(y-y_1),(x-x_1)*(z_2-z_1)-(x_2-x_1)*(z-z_1), b^2*(x^2+y^2)+a^2*(y^2)-a^2*b^2 ];
sol = solve(eq(1),x,eq(2),y, eq(3),z);
sol.x
sol.y
sol.z
end
end
I got the expression value, how do I get the numeric value of x,y,z?
[['x(1)=';'x(2)='],num2str(double(sol.x))]
not work ,shows
??? Error using ==> mupadmex
Error in MuPAD command: DOUBLE cannot convert the input expression into a double array.
If the input expression contains a symbolic variable, use the VPA function instead.
Error in ==> sym.sym>sym.double at 927
Xstr = mupadmex('mllib::double', S.s, 0);
Error in ==> f2 at 38
[['x(1)=';'x(2)='],num2str(double(sol.x))]
If you have access to the Symbolic Toolkit then you do the following:
syms a b k
eq = [k+a/2-173*cos(b), sqrt(3)*a/2-173*sin(b)];
sol = solve(eq(1),a,eq(2),b);
sol.a = simplify(sol.a);
sol.b = simplify(sol.b);
% There are two solutions for 'a' and 'b'
% check residuals for example k=20
subs(subs(eq,{a,b},{sol.a(1),sol.b(1)}),k,20)
% ans = 0.2e-13
subs(subs(eq,{a,b},{sol.a(2),sol.b(2)}),k,20)
% ans = 0.2e-13
Edit 1
Based on new code by OP the matlab script to solve this is:
clear all
clc
syms alpha beta
degree=140/1000000;
p=42164000;
a=6378136.5;
b=6356751.8;
x_1=0;
y_1=p;
z_1=0;
x_2 = p/cos(alpha)*tan(beta);
y_2 = 0;
z_2 = p*tan(alpha);
syms x y z
eq = [(x-x_1)*(y_2-y_1)-(x_2-x_1)*(y-y_1);...
(x-x_1)*(z_2-z_1)-(x_2-x_1)*(z-z_1); ...
b^2*(x^2+y^2)+a^2*(y^2)-a^2*b^2 ];
sol = solve(eq(1),x,eq(2),y,eq(3),z);
sol.x = simplify(sol.x);
sol.y = simplify(sol.y);
sol.z = simplify(sol.z);
pt_1 = [sol.x(1);sol.y(1);sol.z(1)] % First Solution Point
pt_2 = [sol.x(2);sol.y(2);sol.z(2)] % Second Solution Point
x = zeros(100,100);
y = zeros(100,100);
z = zeros(100,100);
for i=451:550
disp(['i=',num2str(i)])
for j=451:550
res = double(subs(pt_1,{alpha,beta},{(1145-i)*degree,(1145-j)*degree}));
x(i-450, j-450) = res(1);
y(i-450, j-450) = res(2);
z(i-450, j-450) = res(3);
end
end
disp('x=');
disp(x);
disp('y=');
disp(x);
disp('z=');
disp(x);
I would try
for i=1:100
k=num2str(i)
[a,b]=solve('100+a/2=173*cos(b)','sqrt(3)*a/2=173*sin(b)','a','b')
end
and then solve the equation