5-point Gaussian Quadrature using constructed approximant in Matlab

[woolley]

Homework Statement

6.3.b highlighted in attachment.
Have solved part a (which gives the approximant used in part b) and problem 3.8 (which gives the original function). 3.8 was definitely solved correctly. Part a could be wrong, but the solution seems OK.
a = acreage
y = yield
from 3.8 - p1,p2,c1,c2 are prices and consumption in periods 1 and 2.

Homework Equations

a = 0.5+0.5*Ey(f(ay)) where Ey is the expected price in terms of y and f(ay)=p1(s).

The Attempt at a Solution

%DEFINE FUNCTION FOR Part b
function [fval] = f63b(y)
fval = 0.5+0.5*Exp;

%5-POINT GAUSSIAN QUADRATURE
[y,w] = qnwlogn(20,0,0.01);
Exp = w'*p1;
fprintf('Exp'); disp(Exp)

a = broyden('f63b',s/2);
fprintf('a'); disp(a)

Gives value for expectation that is accurate, but then the following error:
? Undefined function or variable 'Exp'.
Cannot find solution for a! Should we have 5 nodes or 20? When change to qnwlogn(5,0,0/01) get no value for Exp.

 

[woolley]

Need to evaluate function [p1hat] = p1hat(a,y) using routine funeval(coef,fspace1,s), where s=ay. Matlab gives the following error:

If you get this message, you have not correctly installed the CompEcon Toolbox
Please read the README file for installation details, epsecially the section concerning MEX files
? Error using ==> CEtools/private/chebeval at 22

But toolbox is installed correctly!