Output argument "T" (and maybe others) not assigned during call to "StdAtm".

The first loop works and I don't know why T, rho, and P are not defined when I call the volume_function(4, 0.5).

function [t, h, V] = volume_function(m, dt)

    h = 0;
    hmax = 51000;
    w = 0;
    t = 0;
    [T, ~, P] = StdAtm(h);
    
    volume = [];
    Vmax = 5000;
    V = (m.*4124.*T)./(P);
    volume = [volume, V];
    
    
    time = [];
    height = [];
    height = [height, h];
    

    while h <= hmax || V < Vmax 

        [T, rho, P] = StdAtm(h);
        
        V = (m.*4124.*T)./(P);
        R = (((3./4).*V)./(pi)).^(1./3);
        volume = [volume, V];
        
        mu = 0.000017890.*((T/288.15).^(1.5)).*((288.15+110.4)./(T+110.4));
        Re = (rho.*w.*(2.*R))./(mu);
        Cd = ((24)./(1+Re))+((6)./(1+sqrt(Re)))+0.1;
        D = 0.5.*rho.*(w.^2).*pi.*(R.^2).*Cd;
        
        W = (m+40).*9.81;
        
        rho_H = (P)./(4124.*T);
        B = (4./3).*pi*(R.^3)*(rho-rho_H).*9.81;
        
        Fnet = B - D - W;
        a = Fnet./(m+40);
        
        w = w + a.*dt;
        h = h + w.*dt;
        
        height = [height, h];
        t = t + dt;
        
        time = [time, t];
    end     
end

function [T, rho, P] = StdAtm(h)

    if h >= 0 && h < 11000
        lapse = -0.0065;
        T0 = 288.15;
        P0 = 101325;
        h0 = 0;
        T = T0 + (lapse.*h);
        
        if lapse ~= 0
            P = P0 .* ((T0)/(T0 + lapse.*(h - h0))).^((9.81.* 0.02896)./(8.314.*lapse));
        else
            P = P0 .* exp((-9.81.* 0.02896.*(h-h0))./(8.314.*T0));
        end
        
        rho = P0./(8.314.*T0);
    elseif h >= 11000 && h < 20000
        lapse = 0;
        T0 = 216.65;
        P0 = 22632.1;
        h0 = 11000;
        T = T0 + (lapse.*h);
        
        if lapse ~= 0
            P = P0 .* ((T0)/(T0 + lapse.*(h - h0))).^((9.81.* 0.02896)./(8.314.*lapse));
        else
            P = P0 .* exp((-9.81.* 0.02896.*(h-h0))./(8.314.*T0));
        end
        
        rho = P0./(8.314.*T0);
    elseif h >= 20000 && h < 32000
        lapse = 0.001;
        T0 = 216.65;
        P0 = 5474.89;
        h0 = 20000;
        T = T0 + (lapse.*h);
        
        if lapse ~= 0
            P = P0 .* ((T0)/(T0 + lapse.*(h - h0))).^((9.81.* 0.02896)./(8.314.*lapse));
        else
            P = P0 .* exp((-9.81.* 0.02896.*(h-h0))./(8.314.*T0));
        end
        
        rho = P0./(8.314.*T0);
    elseif h >= 32000 && h < 47000
        lapse = 0.0028;
        T0 = 228.65;
        P0 = 868.019;
        h0 = 32000;
        T = T0 + (lapse.*h);
        
        if lapse ~= 0
            P = P0 .* ((T0)/(T0 + lapse.*(h - h0))).^((9.81.* 0.02896)./(8.314.*lapse));
        else
            P = P0 .* exp((-9.81.* 0.02896.*(h-h0))./(8.314.*T0));
        end
        
        rho = P0./(8.314.*T0);
    elseif h >= 47000 && h <= 51000
        lapse = 0;
        T0 = 270.65;
        P0 = 110.906;
        h0 = 47000;
        T = T0 + (lapse.*h);
        
        if lapse ~= 0
            P = P0 .* ((T0)/(T0 + lapse.*(h - h0))).^((9.81.* 0.02896)./(8.314.*lapse));
        else
            P = P0 .* exp((-9.81.* 0.02896.*(h-h0))./(8.314.*T0));
        end
        
        rho = P0./(8.314.*T0);
    end
end

Answer 1

[Walter Roberson]

Same basic reason as https://www.mathworks.com/matlabcentral/answers/601621-getting-error-unrecognized-function-or-variable#answer_502030