store iterative solutions to matrix

E=input('\nModulus of Elasticity, E(GPa): ');

L=input('Length of each member, L(m): ');

A=input('Area of c/s, A(m^2): ');

Theta=input('Theta(degree): ');

delta_max=input('Maximum Delta(m): ');

a=sind(Theta);

h=L*a;

delta=0:0.01:delta_max;

del=length(delta);

P_L=zeros(1,del);

for i=1:del

P_L(i)=(2*E*A*10^9*a*a* delta(i))/(L*1000);

end

Need to store all iterative values of P_L as a vector

For E = 70, L=5.41, A=0.0006;delta_max=2; theta=33.69;

Last answer = 9.56 * (10^3)

Answer 1

[Star Strider]

Define the range of the independent variables as vectors, then use the ndgrid function to create matrices from them that you can use in the ‘P_L’ assignment (without the indices, since it will be a matrix the same size as the argument matrices) to calculate it from the resulting matrices.

To see the output with respect to each set of variables, use the reshape function on all the argument matrices, and ‘P_L’ to create them each as column vectors. Then use those with the table function to create a table of the results, with appropriate variable names.

There is no way to plot that function against all the independent variables.

[K S Vivek]

but the below logic is working.why?

a=0:0.1:1;

m=5;

F=zeros(1,length(a));

for i=2:length(a)

F(i)=m*a(i);

end

[Star Strider]

It works because you are only using one variable.

Note that:

F = m*a;

also works, and completely avoids the explicit loop.

To do that same sort of calculation with ‘P_L’, and without any explicit loops, assuming all the matrices were created first (note the element-wise operations using the dot operator):

P_L = (2.*E.*A.*1E9.*a.*a.*delta)./(L.*1000);

or if you want to make ‘P_L’ into an anonymous function:

P_L = @(E,A,a,delta,L) (2.*E.*A.*1E9.*a.*a.*delta)./(L.*1000);

and then call it in an assignment to assign the results to another variable.

EDIT — (23 Sep 2020 at 17:19)

To illustrate the approach:

E = 69:71;
L = 5:0.1:6;
a = (5:7)*1E-4;
delta = 0:0.5:2;
theta = 33:0.2:34 ;

P_Lfcn = @(E,A,a,delta,L) (2.*E.*A.*1E9.*a.*a.*delta)./(L.*1000);

[Em,Lm,am,dlm,thm] = ndgrid(E,L,a,delta,theta);

P_L = P_Lfcn(Em,Lm,am,dlm,thm);

TOut = table(Em(:),Lm(:),am(:),dlm(:),thm(:),P_L(:), 'VariableNames',{'E','L','a','delta','theta','P_L'});

First_5_Rows = TOut(1:5,:)
Last_5_Rows  = TOut(end-4:end,:)

with:

First_5_Rows =

  5×6 table

    E      L       a       delta    theta    P_L
    __    ___    ______    _____    _____    ___

    69      5    0.0005      0       33       0 
    70      5    0.0005      0       33       0 
    71      5    0.0005      0       33       0 
    69    5.1    0.0005      0       33       0 
    70    5.1    0.0005      0       33       0 

.

[K S Vivek]

Thank you so much for clarifying my doubt and providing the detailed illustration.

[Star Strider]

As always, my pleasure!