Creating a Function based on Time

Question

Viper224 2016-12-7

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https://ww2.mathworks.cn/matlabcentral/answers/315899-creating-a-function-based-on-time

编辑： Walter Roberson 2016-12-7

As the title suggests I'm trying to create a function of time that computes lift and drag coefficients for the first 5 seconds and then what they are after 5 seconds. I don't have too much MatLab experience so I'm probably not doing this right. Can someone please help?

function[CL, CD, CP] = LiftandDrag(t, CLi, CDi)
t = 1:100;
CDi = 0.01;        %Initial canopy Drag Coefficient
CLi = 0.0;         %Initial canopy Lift Coefficient
if t < 5
    CL = .2*t+CLi;
    CD = 0.038*t+CDi;  %drag coeffcient of chute
    CP = 2;                 %drag of payload
elseif t > 5
    CL = 1;      %Inflated canopy Lift Coefficient
    CD = .2;     %Inflated canopy Drag Coefficient
    CP = 2;      %Payload Drag Coefficient
end

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Answer 1

Walter Roberson 2016-12-7

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/315899-creating-a-function-based-on-time#answer_246382

编辑：Walter Roberson 2016-12-7

在 MATLAB Online 中打开

Vectorize. Logical indexing.

function [CL, CD, CP] = calcLiftAndDrag
    t = 1:100;
    CDi = 0.01;        %Initial canopy Drag Coefficient
    CLi = 0.0;         %Initial canopy Lift Coefficient
    [CL, CD, CP] = LiftandDrag(t, CLi, CDi);
function[CL, CD, CP] = LiftandDrag(t, CLi, CDi)
    CL = zeros(size(t));
    CD = zeros(size(t));
    CP = zeros(size(t));
    mask = t <= 5;
    CL(mask) = .2*t(mask)+CLi;
    CD(mask) = 0.038*t(mask)+CDi;  %drag coeffcient of chute
    CP(mask) = 2;                 %drag of payload
    CL(~mask) = 1;      %Inflated canopy Lift Coefficient
    CD(~mask) = .2;     %Inflated canopy Drag Coefficient
    CP(~mask) = 2;      %Payload Drag Coefficient