# solving symbolic array to output a numerical solution

3 Ansichten (letzte 30 Tage)
Samuel Casallas am 26 Mär. 2021
Bearbeitet: VBBV am 1 Jun. 2023
Hi there, I was wondering if I could get some feedback on a potential solution for this problem. I am trying to solve for ma3 and obtain a numerical value for each value used in the FLcD3 array. However, the output of Ma3 is a struct with fields. How do I get it so the solution is an array with the numerical values? I'm guessing I would need some form of a for loop but i'm not quite sure how to set it up.
PSW = 0.36:0.03:0.69;
L12 = PSW*TL;
D = 0.03;
Ma4 = 1;
P4 = 1.013;
Lc3 = TL-L12;
FLcD3 = 4*f*Lc3/D;
ma3 = sym('ma3', [1 length(PSW)]) ;
eqn1 = (-1./G).*(1-ma3.^-2)+((G+1)./(2.*G)).*log((((G+1)./2).*ma3.^2)./(1+((G-1)./2).*ma3.^2)) == FLcD3;
Ma3 = vpasolve(eqn1,ma3)
%This is the output I get
Ma3 =
ma31: [1×1 sym]
ma32: [1×1 sym]
ma33: [1×1 sym]
ma34: [1×1 sym]
ma35: [1×1 sym]
ma36: [1×1 sym]
ma37: [1×1 sym]
ma38: [1×1 sym]
ma39: [1×1 sym]
ma310: [1×1 sym]
ma311: [1×1 sym]
ma312: [1×1 sym]
##### 0 Kommentare-2 ältere Kommentare anzeigen-2 ältere Kommentare ausblenden

Melden Sie sich an, um zu kommentieren.

### Antworten (2)

madhan ravi am 26 Mär. 2021
Bearbeitet: madhan ravi am 26 Mär. 2021
struct2array(Ma3)
##### 2 KommentareKeine anzeigenKeine ausblenden
Samuel Casallas am 26 Mär. 2021
I had previously tried that but I get the error:
Unrecognized function or variable 'struct2array'.
Is there a work around this?
madhan ravi am 27 Mär. 2021

Melden Sie sich an, um zu kommentieren.

VBBV am 1 Jun. 2023
Bearbeitet: VBBV am 1 Jun. 2023
From the reference link given by @madhan ravi, you can use struct2cell function and later convert the cell to double array using cell2mat function. And i think both struct2cell & cell2mat are documented well in Matlab
Ma3 = vpasolve(eqn1,ma3)
cell2mat(struct2cell(Ma3))
##### 0 Kommentare-2 ältere Kommentare anzeigen-2 ältere Kommentare ausblenden

Melden Sie sich an, um zu kommentieren.

### Kategorien

Mehr zu Conversion Between Symbolic and Numeric finden Sie in Help Center und File Exchange

### Community Treasure Hunt

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

Start Hunting!

Translated by