dblquad function handle help
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Hello. I'm facing the following problem:
dblquad('power(x,3)*power(y,3)',0,1,0,1)
Works perfectly fine! But...
dblquad('x^3*y^3',0,1,0,1)
Gives the following error...
Error using inlineeval (line 15)
Error in inline expression ==> x^3*y^3
Inputs must be a scalar and a square matrix.
To compute elementwise POWER, use POWER (.^) instead.
Error in inline/subsref (line 24)
INLINE_OUT_ = inlineeval(INLINE_INPUTS_, INLINE_OBJ_.inputExpr, INLINE_OBJ_.expr);
Error in quad (line 72)
y = f(x, varargin{:});
Error in dblquad>innerintegral (line 82)
Q(i) = quadf(intfcn, xmin, xmax, tol, trace, y(i), varargin{:});
Error in quad (line 72)
y = f(x, varargin{:});
Error in dblquad (line 58)
Q = quadf(@innerintegral, ymin, ymax, tol, trace, intfcn, ...
So, what I've tried is:
dblquad('x.^3*y.^3',0,1,0,1)
And it works perfectly well. The real problem is that I must define a vector with functions:
k=1;
syms x y
for i=1:n;
for j=1:n;
f(k)=power(x,1+i)*power(y,1+j);
k=k+1;
end
end
And then I must deliver the following code to dblquad:
dblquad(char(f(k)),0,1,0,1);
And char(f(k)) gives me 'x^(1+i)*y^(j+1)' form, which dblquad can't handle. (Noting that "i" and "j" are now real numbers, arbitrary.)
Any ideas?
采纳的回答
Walter Roberson
2012-5-23
0 个投票
char() isn't going to give you that unless you are using the symbolic toolbox. If you are, see matlabFunction()
Also see vectorize()
Passing strings in instead of function handles is no longer recommended.
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