Filter löschen
Filter löschen

How to reduce decimal places displayed in symbolic matrix?

12 Ansichten (letzte 30 Tage)
Hi, I have a matrix which contains symbolic elements. I'd like to decrease decimal count display to enhance readability.
Here is my matrix. I just copied the output of an attempt, please ignore the vpa.
syms t Omega
eta(Omega) = [(vpa("8000.0")*cos(Omega*t + vpa("0.78539816339744830961566084581988"))*(vpa("26838195793182970854745861920038.0")*Omega^2 - vpa("2.4154462400944206989319304935157e+34")))/(vpa("4.153837486827862102824397063376e+34")*Omega^4 - vpa("3.7425286527196553136998040116897e+37")*Omega^2 + vpa("3.6554306435273366948203088051441e+37")); -(vpa("0.0152587890625")*cos(Omega*t + vpa("0.78539816339744830961566084581988"))*(vpa("9.7133610940578263277504767935649e+35")*Omega^2 - vpa("9.4976141444561753442642817416859e+35")))/(vpa("4.153837486827862102824397063376e+34")*Omega^4 - vpa("3.7425286527196553136998040116897e+37")*Omega^2 + vpa("3.6554306435273366948203088051441e+37"))]
format short
does NOT help. I believe it's because the matrix has symbolic elements.

Akzeptierte Antwort

Walter Roberson
Walter Roberson am 9 Dez. 2022
vpa(eta, DIGITS)
Note that exponents might not be affected in some cases
  2 Kommentare
Ali
Ali am 10 Dez. 2022
Hi, thanks for your answer. Unfortunately, this doesn't work when assigning to a symbolic function.
>> q_hat(Omega) = vpa(q_hat(Omega),3)
q_hat(Omega) =
(27746.870093822479248046875 + 27746.870093822479248046875i)/(1000000.0*Omega^4 - 900981000.0*Omega^2 + 880012917.0)
-(0.0000000000000022737367544302526432562150870628*(Omega^2*(6219777023972212736.0 + 6219777023972212736.0i) - 5591697720268541657088.0 - 5591697720268541657088.0i))/(1000000.0*Omega^4 - 900981000.0*Omega^2 + 880012917.0)
>> q_hat = vpa(q_hat(Omega),3)
q_hat =
(2.77e+4 + 2.77e+4i)/(1.0e+6*Omega^4 - 9.01e+8*Omega^2 + 8.8e+8)
-(2.27e-15*(Omega^2*(6.22e+18 + 6.22e+18i) - 5.59e+21 - 5.59e+21i))/(1.0e+6*Omega^4 - 9.01e+8*Omega^2 + 8.8e+8)
>>
Walter Roberson
Walter Roberson am 10 Dez. 2022
It looks to me as if at the time you create a symbolic function using the notation of symbolic subscript on the left-hand side, it looks at the current digits setting and locks that in to the function.
However, if the right hand side of the expression is a symbolic function and you do not use the symbolic variable subscript on the left hand side, it does not do that.
syms x
f(x) = sym('0.0000000000000022737367544302526432562150870628')*x
f(x) = 
g(x) = vpa(f,3)
g(x) = 
h = vpa(f,3)
h(x) = 
digits(5)
h(x) = vpa(f,3)
h(x) = 

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (0)

Produkte


Version

R2022a

Community Treasure Hunt

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

Start Hunting!

Translated by