How to generate tones with varying F0, F2, duration and risetime

Hello everyone! I'm trying to generate a range of stimuli varying across different acoustic characteristics: F0, F2, duration and risetime. I managed to put together changes across F0, F2, and duration, but the script fails when I add the additional loop to generate changes in risetime (I marked those added lines as %new in my script). Is there anything I'm missing here why these sounds cannot be generated? Any suggestions/hints would be super appreciated.

clear all

F0s = [100 100*2^(3/12)];
F2s = [2040 2040*2^(6/12)];
durs = [0.100 0.325];
RTms = [0.015 0.150];

fs = 44100;

%amplitude_rampup =
%sin(0:(pi/2)/floor(0.010*fs):pi/2-((pi/2)/floor(0.010*fs))).^2; %replaced
%amplitude_rampdown =
%sin(pi/2:(pi/2)/ceil(0.010*fs):pi-((pi/2)/ceil(0.010*fs))).^2; %replaced

for n = 1:length(F0s)
    for m = 1:length(F2s)
        for p = 1:length(durs)
            for rd = 1:length(RTms) %new
            F0 = F0s(n);
            F2 = F2s(m);
            dur = durs(p);
            rtm = RTms(rd); %new
            
            ramp_dur = RTms(rd); %new
            ramp = 0:1/ceil(ramp_dur*fs):1; %new
            amplitude_rampup = ramp; %new
            amplitude_rampdown = fliplr(ramp); %new
            amplitude_mod = [amplitude_rampup ones(1, fix(dur*fs)-2*length(amplitude_rampup)) amplitude_rampdown]; %added fix to force the result to integer format
            
            time_points = 1/fs:1/fs:dur;
            pitch_contour = [];
            pitch_contour(1:length(time_points)) = F0;
            base_stim = [];
            base_stim(1:length(time_points)) = 0;
            F =  [F2];
            BW = [100];
            R = exp(-pi*BW/fs);     % Pole radii
            theta = 2*pi*F/fs;      % Pole angles
            poles = R .* exp(j*theta); % Complex poles
            B = 1;  A = real(poly([poles,conj(poles)]));
            for q = 1:40
                previous_phase = 0;
                for r = 1:length(pitch_contour)
                    if pitch_contour(r) > 0
                        base_stim(r) = base_stim(r) + 0.5 * sin(2 * pi * pitch_contour(r) * q * (1/fs) + previous_phase);
                        previous_phase = mod(2*pi*pitch_contour(r) * q * (1/fs) + previous_phase,2*pi);
                    end
                end
            end
            base_stim = filter(B, A, base_stim);
            base_stim = base_stim.*amplitude_mod;
            base_stim = (base_stim ./ max(abs(base_stim)));
            base_stim = base_stim.*0.9;
            
            audiowrite(['F0' num2str(F0) '_F2' num2str(F2) '_dur' num2str(dur) 'risetime' num2str(rtm) '.flac'],base_stim,fs);
            end %new
        end
    end
end

[Geoff Hayes]

Magdalena - when I run your code, I see the following error

Arrays have incompatible sizes for this operation.

Error in XX (line YY)
            base_stim = base_stim.*amplitude_mod;

because the dimensions of base_stim and amplitude_mod are different: 1x4410 vs 1x13232. This occurs on the second iteration of the innermost loop when rd is 2 and ramp_dur is 0.15. You will want to take this into account when determing base_stim.