How can I convert symbolic function into non symbolic function.

2018 7 25
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更新时间：2018 7 26
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Hi. I am trying to make a GUI algorithm and just realize that syms (from the symbolic toolbox) is not working for the compiler.
Is there any way I can use another command or change function into non-symbolic function?
My function has the following form.
syms A E B
diff_A = diff(exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),A);
A=x(1)

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Star Strider
Star Strider 2018-7-25

0 个投票

Use the matlabFunction function:
syms A E B pre k normal_stress
diff_A = diff(exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),A);
diff_A_fcn = matlabFunction(diff_A)
to get:
diff_A_fcn =
function_handle with value:
@(A,B,E,k,normal_stress,pre)B.*pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A).*exp(-(pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A)).^B).*(pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A)).^(B-1.0)

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ChinUk
ChinUk 2018-7-26
Thank you for the answer. I will try to apply it.
Star Strider
Star Strider 2018-7-26
As always, my pleasure.
You will find it easier to use as:
diff_A_fcn = @(A,B,E,k,normal_stress,pre) B.*pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A).*exp(-(pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A)).^B).*(pre.*exp(-E./(k.*(normal_stress+2.7316e2))).*exp(-A)).^(B-1.0);

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KSSV
KSSV 2018-7-25

0 个投票

How about using anonymous function?
diff_A = @(A,B,E) diff([exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),A]);

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ChinUk
ChinUk 2018-7-26
Thank you for your help. I really appreciate it.
ChinUk
ChinUk 2018-7-26
编辑：ChinUk 2018-7-26
Thank for your answer, just a little quick question.
As you see, I try to make differential function without using the syms command.
and how can I replace 'eval' command? deval function is not so useful.
the full function had the following format.
diff_A = diff(exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),A);
diff_E = diff(exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),E);
diff_B = diff(exp(-(pre/(exp(A)*exp(E./(k*(273.16+normal_stress)))))^B),B); A=x(1); E=x(2); B=x(3);
g = [eval(diff_A) eval(diff_E) eval(diff_B)];

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