adding for loop with linspace with many variables

Hi ,

I am trying to run this script but keep having errors ,please help

wg=0.18;
ws=0.12;
a=0.425;
b=2.353;
c=0.06;
d=0.18;
e=0.12;
p1 = 0.015604;
p2 = -1.4201;
p3 = 53.8951;
p4 = -1091.1818;
p5 = 12425.3578;
p6 = -75422.3333;
p7 = 190602.4449;
qp1 = 1.1584;
qp2 = -110.2867;
qp3 = 4362.3758;
qp4 = -91752.2953;
qp5 = 1082176.2735;
qp6 = -6786040.7706;
qp7 = 17674223.7811;

%x= linspace(10,30,20); %pitta
r= sqrt(410-(x.^2));
rr=  (r).^2;
y1= @(x) (r.*wg);
%A = @(x) p1*x.^6 + p2*x.^5 + p3*x.^4 + p4*x.^3 + p5*x.^2 + p6.*x + p7 ;
%B= @(x) qp1*x.^6 + qp2*x.^5 +qp3*x.^4 + qp4*x.^3 +qp5*x.^2 + qp6.*x + qp7;
R =  sqrt(235.72-rr);
T=  @(x) 2.353*(R./r);
 x= linspace(10,30,20);
for i=10:20r(i) 
    r(i)= sqrt(410-(i.^2));
rr(i)=  (r(i)).^2;
A(i) =  p1*i.^6 + p2*i.^5 + p3*i.^4 + p4*i.^3 + p5*i.^2 + p6.*i + p7 ;
B(i)= qp1*i.^6 + qp2*i.^5 +qp3*i.^4 + qp4*i.^3 +qp5*i.^2 + qp6.*i + qp7;
R(i) =  sqrt(235.72-rr(i));
    T(i)=  2.353*(R(i)./r(i));
yup(i) =  A5(x).*T(x)+B5(x);
end
ydown=@(x) A5-B5.*T;
y2=  yup./ydown;
y3= atan(y2)+2*pi;
plot (x,y1(x))
hold on
plot (x,A(x))
plot (x,B(x))

[per isakson]

Include the full error message in your question.

Is r(i) in this statement a typing error? It's not correct Matlab syntax.

for i=10:20r(i)

[dana akil]

It is a trping error

[dana akil]

Conversion to function_handle from double is not possible.

[dana akil]

I just need it to calculate all the variables one by one

for i=10

r(10) is

rr(10 ) is then calculate A(10 )

it keeps giving me one value

Answer 1

[Alberto Cuadra Lara]

Hello Dana,

There are inconsistencies in your code:

• x is not defined before use it
• The loop is not properly defined, for i = 10 : 20 * r(i) ??
• I do not see why you need to use a for loop here. MATLAB works great using vectorization.
• A5 and B5 are not defined.

Please, clarify these points.

Best,

Alberto

[dana akil]

I removed the for loop and it works fine

Thank you

But I have adiffrent proplem now

Array indices must be positive integers or logical values.

at y2 line

wg=0.18;
ws=0.12;
a=0.425;
b=2.353;
c=0.06;
d=0.18;
e=0.12;
p1 = 0.015604;
p2 = -1.4201;
p3 = 53.8951;
p4 = -1091.1818;
p5 = 12425.3578;
p6 = -75422.3333;
p7 = 190602.4449;
qp1 = 1.1584;
qp2 = -110.2867;
qp3 = 4362.3758;
qp4 = -91752.2953;
qp5 = 1082176.2735;
qp6 = -6786040.7706;
qp7 = 17674223.7811;

%x= linspace(10,30,20); %pitta
r= sqrt(410-(x.^2));
rr=  (r).^2;
y1= @(x) (r.*wg);
A = @(x) p1*x.^6 + p2*x.^5 + p3*x.^4 + p4*x.^3 + p5*x.^2 + p6.*x + p7 ;
B= @(x) qp1*x.^6 + qp2*x.^5 +qp3*x.^4 + qp4*x.^3 +qp5*x.^2 + qp6.*x + qp7;
R =  sqrt(235.72-rr);
T= 2.353*(R/r);
 x= linspace(10,30,20);

r= sqrt(410-(x.^2));
rr =  (r).^2;


yup = @(x)  A(x)*T+B(x);

ydown=@(x) A(x)-B(x)*T;

 figure(1)
%plot(x , yup(x))
%hold on
%plot(x , ydown(x))

y2(x)=  real(yup(x)/ydown(x));
y3(x)= real(atan(y2)+2*pi);
figure(2)
plot (x,y3(x))
plot (x,y1(x))

hold on 

Answer 2

[Alberto Cuadra Lara]

Hi Dana,

I'm not sure if this is what you expect, but here is the code without errors. I have changed the handle functions to vectors.

% Constants
wg = 0.18;
ws = 0.12;
a = 0.425;
b = 2.353;
c = 0.06;
d = 0.18;
e = 0.12;
p1 = 0.015604;
p2 = -1.4201;
p3 = 53.8951;
p4 = -1091.1818;
p5 = 12425.3578;
p6 = -75422.3333;
p7 = 190602.4449;
qp1 = 1.1584;
qp2 = -110.2867;
qp3 = 4362.3758;
qp4 = -91752.2953;
qp5 = 1082176.2735;
qp6 = -6786040.7706;
qp7 = 17674223.7811;

% Definitions
x = linspace(10, 30, 20);

% Calculations
r = sqrt(410 - (x.^2));
rr = r.^2;
A = p1*x.^6 + p2*x.^5 + p3*x.^4 + p4*x.^3 + p5*x.^2 + p6.*x + p7 ;
B = qp1*x.^6 + qp2*x.^5 + qp3*x.^4 + qp4*x.^3 + qp5*x.^2 + qp6.*x + qp7;
R =  sqrt(235.72 - rr);
T = 2.353*(R ./ r);
yup = A .* T + B;
ydown = A - T .* B;
y1 = real(r * wg);
y2 = real(yup ./ ydown);
y3 = real(atan(y2) + 2*pi);

% Plot figure
figure;
hold on;
plot (x, y3)
plot (x, y1)

[dana akil]

Thank you

many thanks