Unrecognized function or variable in a code

2024 6 19
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更新时间：2024 6 19
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% param value
clear all; close all;
% p is constant and q varies
k0 = 0.0000169; u=0.6; p=536.2; q=0.0000376;
% your function
k = @(t,u) (k0 + (p*k0.^u-q*k0).*t.^a/gamma(a+1) +(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)/gamma(2*a+1)...
+(p*k0.^u-q*k0).*((p*u*k0.^u-q).^2-p*u.*(u-1)*k0.^(u-1)./2).*t.^(3*a)/gamma(3*a+1));
% grid
%t = linspace(0,0.1);
%u = linspace(0.3,0.9);
%[T,U] = meshgrid(t,q);
t = linspace(0,0.1,50);
a = linspace(0.3,0.9,50);
[T,A] = meshgrid(t,a);
% evaluate function
Z = k(T,A);
Unrecognized function or variable 'a'.

Error in solution>@(t,u)(k0+(p*k0.^u-q*k0).*t.^a/gamma(a+1)+(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)/gamma(2*a+1)+(p*k0.^u-q*k0).*((p*u*k0.^u-q).^2-p*u.*(u-1)*k0.^(u-1)./2).*t.^(3*a)/gamma(3*a+1)) (line 6)
k = @(t,u) (k0 + (p*k0.^u-q*k0).*t.^a/gamma(a+1) +(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)/gamma(2*a+1)...
% plot
figure
surf(T,A,Z)
%surf(T,Q,Z,'facecolor','none')
xlabel('t');
ylabel('\mu');
zlabel('k(t)')

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 采纳的回答

Cris LaPierre
Cris LaPierre 2024-6-19

0 个投票

You create an anonymous function, k, that uses a variable a in the function. However, this variable was not defined at the time the anonymous function was defined.

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Cris LaPierre
Cris LaPierre 2024-6-19
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Perhaps you meant to define a=0.6 instead of u?
% param value
% p is constant and q varies
k0 = 0.0000169; a=0.6; p=536.2; q=0.0000376;
% your function
k = @(t,u) (k0 + (p*k0.^u-q*k0).*t.^a/gamma(a+1) +(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)/gamma(2*a+1)...
+(p*k0.^u-q*k0).*((p*u*k0.^u-q).^2-p*u.*(u-1)*k0.^(u-1)./2).*t.^(3*a)/gamma(3*a+1));
% grid
t = linspace(0,0.1,50);
u = linspace(0.3,0.9,50);
[T,A] = meshgrid(t,u);
% evaluate function
Z = k(T,A);
% plot
figure
surf(T,A,Z)
xlabel('t');
ylabel('\mu');
zlabel('k(t)')
Mathew
Mathew 2024-6-19
Ran in:
Ran in:
Here is exactly the code that I wanted to run.
The code does not produce an image with MATLAB 2023b.
Warning: Matrix is singular to working precision.
% Warning: Matrix is singular to working precision.
% That is the response that I get.
% param value
clear all; close all;
% p is constant and q varies
k0 = 0.0000169; u=0.6; p=536.2; q=0.0000376;
k = @(t,a) (k0 + (p*k0.^u-q*k0).*t.^a/gamma(a+1) +(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)/gamma(2*a+1)...
+(p*k0.^u-q*k0).*((p*u*k0.^u-q).^2-p*u.*(u-1)*k0.^(u-1)./2).*t.^(3*a)/gamma(3*a+1));
% grid
t = linspace(0,1,50);
a = linspace(0.25,0.85,50);
[T,A] = meshgrid(t,a);
% evaluate function
Z = k(T,A);
Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 4.818625e-53.
Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 1.825871e-53.
Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 6.413452e-54.
% plot
figure
surf(T,A,Z)
xlabel('t');
ylabel('\alpha');
zlabel('k(t)')
Steven Lord
Steven Lord 2024-6-19
Ran in:
Ran in:
You likely want to use array division (element-wise) rather than matrix division.
% p is constant and q varies
k0 = 0.0000169; u=0.6; p=536.2; q=0.0000376;
k = @(t,a) (k0 + (p*k0.^u-q*k0).*t.^a./gamma(a+1) +(p*k0.^u-q*k0).*(p*u*k0.^u-q).*t.^(2*a)./gamma(2*a+1)...
+(p*k0.^u-q*k0).*((p*u*k0.^u-q).^2-p*u.*(u-1)*k0.^(u-1)./2).*t.^(3*a)./gamma(3*a+1));
% grid
t = linspace(0,1,50);
a = linspace(0.25,0.85,50);
[T,A] = meshgrid(t,a);
% evaluate function
Z = k(T,A);
% plot
figure
surf(T,A,Z)
xlabel('t');
ylabel('\alpha');
zlabel('k(t)')

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