Solving equation with symbolic vector variable

35 visualizaciones (últimos 30 días)
Delia Bosshart
Delia Bosshart el 19 de Abr. de 2021
Comentada: Delia Bosshart el 19 de Abr. de 2021
I want to solve an equation, a b c d are known vectors and x is the symbolic vector variable I want to solve for.
In the output I get only the 'names' of the elements (x1, x2, ...) How do I get the values of x1,x2 ? Any help is much appreciated.
SIMPLIFIED PROBLEM:
input:
a = [1 2 3 4];
x = sym('x', [1 4]);
eqn = a + 4.*x == x;
vpasolve(eqn, x)
Output:
ans =
struct with fields:
x1: [1×1 sym]
x2: [1×1 sym]
x3: [1×1 sym]
x4: [1×1 sym]
REAL PROBLEM:
Input:
a = data{23:29,6}; %q_inc
b = data{23:29,16}; %q_losses
c = data{23:29,15}; %rho_char
d = data{23:29,14}; %betta_char
x = sym('x', [1 9]);
eqn = (a - b + 6.96.*x + (6-(31.*c)./1000).*x./60*1000 + 31.*c./1000.*d./60*1000)*0.0081 - 0.1824 - x == 0;
vpasolve(eqn,x)
Output:
ans =
struct with fields:
x1: [1×1 sym]
x2: [1×1 sym]
x3: [1×1 sym]
x4: [1×1 sym]
...

Respuesta aceptada

Stephan
Stephan el 19 de Abr. de 2021
use the dot-notation
a = [1 2 3 4];
x = sym('x', [1 4]);
eqn = a + 4.*x == x;
sol_x = vpasolve(eqn, x)
sol_x.x1
sol_x.x2
sol_x.x3
sol_x.x4
  2 comentarios
Walter Roberson
Walter Roberson el 19 de Abr. de 2021
a = [1 2 3 4];
x = sym('x', [1 4]);
eqn = a + 4.*x == x;
temp = struct2cell(vpasolve(eqn, x));
vertcat(temp{:})
ans = 
Delia Bosshart
Delia Bosshart el 19 de Abr. de 2021
Thank you!

Iniciar sesión para comentar.

Más respuestas (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by