Impulse response acoustic information calculator

Hello can someone help me. I can not figure out how to get this code to run. it is supposed to estimate reverberation time based on room size and absorption. It returns a error of invalidcoeff: abs_coeff so I see a probelm in the first line but I do not understand what to do about it. I tried putting numbers in but the code did not like that either. Can anyone tell me what i am doing wrong? :

function rt = rtEst(abs_coeff,room,formula)

%RTEST Estimate reverberation time based on room size and absorption

%

% RT = IOSR.ACOUSTICS.RTEST(ABS_COEFF,ROOM) estimates the reverberation

% time (RT60) for a shoebox-shaped room, with average absorption

% coefficient ABS_COEFF, and dimenions ROOM=[L W H] (in metres). An RT

% estimate is returned for each element of ABS_COEFF.

%

% RT = IOSR.ACOUSTICS.RTEST(ABS_COEFF,ROOM,FORMULA) allows the formula to

% be specified. The options are 'sabine' (default), or 'eyring'.

% Copyright 2016 University of Surrey.

assert(isnumeric(abs_coeff), 'iosr:rtEst:invalidCoeff', 'abs_coeff should be numeric')

assert(isnumeric(room) & numel(room)==3 & isvector(room), 'iosr:rtEst:invalidRoom', 'room should be a 3-element numeric vector')

if nargin<3

formula = 'sabine';

end

assert(ischar(formula), 'iosr:rtEst:invalidFormula', 'formula should be a character array (string)')

l = room(1);

w = room(2);

h = room(3);

vol = prod(room);

surf_area = (2*l*w) + (2*l*h) + (2*w*h);

switch lower(formula)

case 'sabine'

rt = (0.161*vol)./(surf_area.*abs_coeff);

case 'eyring'

rt = (0.161*vol)./(-surf_area.*log(1-abs_coeff));

otherwise

error('iosr:rtEst:unknownFormula','Unknown formula')

end

end

[Mark Thompson]

Can you please post your code for how you call this function? I have just tested it with several different scenario's and the only time I get it to generate the error you are experiencing is when I pass a "non-numeric" value as the absorption coefficient?!