Solving equation with symbolic vector variable

53 Ansichten (letzte 30 Tage)
Delia Bosshart
Delia Bosshart am 19 Apr. 2021
Kommentiert: Delia Bosshart am 19 Apr. 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]
...

Akzeptierte Antwort

Stephan
Stephan am 19 Apr. 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 Kommentare
Walter Roberson
Walter Roberson am 19 Apr. 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 am 19 Apr. 2021
Thank you!

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (0)

Community Treasure Hunt

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

Start Hunting!

Translated by