error with function handles

[simone marras]

Hi,

I am trying to call a function that accepts a function handle as
argument. My functions are all defined within the same directory where
myfun.m rerturns a simple expression as:

function y = myfun(x)
     y = 10*exp(-50.0*abs(x)) - 0.01/((x-0.5).*(x-0.5) + 0.001) +
5.0*sin(5.0*x);
endfunction

and midpntc is defined as:

function [Int] = midpntc(a, b, m, function)

    h=(b-a)/m
        x=[a+h/2:h:b];
        
        k = max(size(x));
        y = eval(fun);
        
        if size(y) == 1, y = diag(ones(k))*y; end
        
        int = h*sum(y);



when I call midpntc in octave as:

>> Int = midpntc(0, 1, 10, "myfun")

I obtain the following error:

 midpntc(0,1,10,"myfun")
h =  0.10000
error: `x' undefined near line 2 column 9
error: evaluating binary operator `.^' near line 2, column 10
error: evaluating binary operator `-' near line 2, column 13
error: evaluating binary operator `-' near line 2, column 17
error: evaluating binary operator `./' near line 2, column 6
error: evaluating assignment expression near line 2, column 3
error: called from `myfun'
error: evaluating assignment expression near line 13, column 4
error: called from `midpntc' in file
`/home/simone/Documents/scientific/CFD/myCFD_library/ATMOSPHERE_miscellanea/TMP/midpntc.m'


while, if I use the syntax

>> Int = midpntc(0, 1, 10, @myfun)

the error that I get is:

h =  0.10000
error: octave_base_value::convert_to_str_internal (): wrong type
argument `function handle'
error: eval: expecting std::string argument
error: evaluating assignment expression near line 13, column 4
error: called from `midpntc' in file
`/home/simone/Documents/scientific/CFD/myCFD_library/ATMOSPHERE_miscellanea/TMP/midpntc.m'


Could anyone help me with this issue?
Thank you very much in advance,

S.

-- 
Simone Marras, Ph.D. candidate
Barcelona Supercomputing Center
Universitat Politecnica de Catalunya
Avd. Diagonal 647,
Edificio H, planta 10
Barcelona, 08028
SPAIN
Tel.: (+34) 93 4011744
web: www.cranfield.ac.uk/~c086030